Original Article EVOLUTIONARY PSYCHOLOGY: an EMERGING INTEGRATIVE PERSPECTIVE WITHIN the SCIENCE and PRACTICE of PSYCHOLOGY

The Human Nature Review ISSN 1476-1084 URL of this document http://human-nature.com/nibbs/02/ep.html

Human Nature Review 2 (2002) 17-61

Original Article EVOLUTIONARY PSYCHOLOGY: AN EMERGING INTEGRATIVE PERSPECTIVE WITHIN THE SCIENCE AND PRACTICE OF PSYCHOLOGY

Leif Edward Ottesen Kennair

Abstract Evolutionary Psychology (EP) is an emerging integrative approach to the study of Human Nature, founded upon evolutionary biological theory and cognitive science. This article evaluates the theoretical foundations and implications of EP from a Scientist- Practitioner perspective. EP is contrasted with its antecedent, human sociobiology, and theoretical differences are discussed. Cosmides & Tooby’s EP is described; including EP’s model of mind, the need for a computational theory and how this is provided by functional adaptationism, the strategic modelling of the past needed to make evolutionary inferences, and the role of present ontogenetic environment on the development and function of adaptations. The adaptationist approach to Human Nature is controversial; therefore the scientific validity of this approach is evaluated; the critique is not found convincing. The perceived paradox of EP’s focus compared with behavioral genetics and comparative psychology is resolved. The compatibility between learning psychology and EP is addressed. Finally EP’s implications for the mainstream academic fields of psychology – cognitive, social, developmental, and personality psychology - and to the practice of clinical psychology – Evolutionary Psychopathology - are considered. EP is a growing, influential and promising field of study, and potentially a unifying theory of psychology.

Keywords: Evolutionary Psychology – Human Nature – Modular Mind –Human Sociobiology – Adapta- tionism - Scientist-Practitioner – Evolutionary Psychopathology

I. Introduction “Is it not reasonable to anticipate that our under- “In the distant future I see open fields for far standing of the human mind would be aided more important researches. Psychology will be greatly by knowing the purpose for which it was based on a new foundation, that of the necessary designed?” acquirement of each mental power and capacity George C. Williams, 1966, p. 16. by gradation.” Charles Darwin, 1859/1996, p. 394. With the publication of On the Origin of the Species, Charles Darwin (1859/1996) changed “Nothing in Biology Makes Sense Except in the our world (Dawkins, 1976/1989; Mayr, 1983). Light of Evolution” There is no longer any reason to doubt the gen- Theodosius Dobzhansky, 1973, p. 125. eral idea of evolution. This article will not argue

Human Nature Review, Volume 2, 2002, 17 Human Nature Review 2 (2002) 17-61 against creationism; this is done at length else- heritability that was perfectly compatible with where (e.g. Futuyma, 1983). This article accepts natural selection. The synthesis of Darwin and the less controversial stance that of the two ex- Mendel is today’s mainstream evolutionary the- planations, evolution is the scientific explana- ory. tion. It is the preferred theory when attempting to EP is a synthesis of modern evolutionary perform a scientific investigation of the nature of theory, studies of behaviour inspired by evolu- any biological phenomenon (Ridley, 1996), like tionary theory, and cognitive psychology. It pro- Human Nature. poses an integrative perspective for psychology, This article is founded upon two basic and as such, it aspires to become the first real principles. First, humans are products of evolu- unifying paradigm of psychology (Buss, 1995a, tion, as are any other biological phenomena. 1995b; La Cerra & Kurzban, 1995). Many will Second, Human Nature is a biological phenome- see this as meaning that EP is a new attempt at non. It is also a sociocultural phenomenon, but promoting the ideas of human sociobiology as culture is a product of Human Nature, culture (SB), including the idea of reducing psychology is also a biological phenomenon. Thus psychol- to biology. One of the first problems in present- ogy is a life science, and is approached in an ing any evolutionary perspective to Human Na- anti-dualistic manner. The theory of evolution is ture is the association to human SB; therefore therefore essential to studying psychology. This this needs to be dealt with first (Section II). The has been accepted within Evolutionary Psychol- basic theoretical principles that constitute EP ogy (EP) (Cosmides & Tooby, 1987; Tooby, will then be presented (Section III). Not all theo- 1988); and has resulted in Charles Darwin being reticians accept the functional, adaptationist listed as one of psychology’s pioneers as the fa- stance of mainstream evolutionary science. ther of EP (Masterton, 1998). Darwin contrib- Gould and Lewontin’s call for Pluralism (1979, uted to psychology in so many ways prior to EP Gould, 1983, 1991, 1993, 1997a, 1997b, 1997c; that this seems a limited focus; his studies of Lewontin, 1979; Rose, Lewontin & Kamin, children inspired Freud’s interest in child psy- 1984) has raised many issues critical to an evolu- chology (Sulloway, 1979/1992), and his studies tionary explanation of Human Nature. These of emotional expressions (Darwin, 1872/1998) controversies must be addressed (Section IV). still generate research (Ekman, 1998). His work There exist at, least three, wrongfully perceived has formed and generated fields such as psycho- paradoxes of EP. These follow from the preju- analysis, comparative psychology, behaviourism, dice that EP is theoretically on a par with SB, psychometrics, behavioural genetics, ethology, and need to be resolved in order to see how EP ecology (Gangestad, 1995), and even existential- relates to both evolutionary theory and psychol- ism. ogy (Section V). Finally, if EP is to integrate The Modern Synthetic theory of evolu- psychology within a theoretical framework that tion is a synthesis of Darwin’s principle of natu- not only enables different areas of psychology to ral selection and population genetics (Mayr, communicate, but also different levels of analy- 1978). Darwin’s own theory of heritability was sis, from biology to culture, then EP must show logically opposed to the possibility of a mecha- an ability to rigorously inform research, strin- nism such as natural selection being able to op- gently discipline theory that is incompatible with erate (Ridley, 1996), it also included the idea of empirical findings across sciences, and provide a heritability of acquired traits. This idea is often conceptual level acceptable to most practitioners presented as Lamarckism, but it would be neither within the field. It is the aim of Section VI to historically correct nor fair to Lamarck, to sug- show this. gest that he was but the spokesman of a com- The main questions to be addressed in monly held belief. In this article, where neces- this paper are thus: sary, the idea of heritability of acquired traits Is EP a theoretically valid science? Its will nonetheless be called Lamarckian- ability to synthesise evolutionary theory and inheritance. This idea was finally laid to rest by psychology such that it presents both theories in Weismann’s rediscovery of Mendelian “genet- a form acceptable to the different fields of study ics” (Mayr, 1978; Ridley, 1996), a theory of is important. Human SB had several problems in

Human Nature Review, Volume 2, 2002, 18 Human Nature Review 2 (2002) 17-61 that respect, and met claims of lack of theoretical inspired by W. D. Hamilton’.” Dawkins’ validity from most disciplines. EP is more on a (1976/1989) own The Selfish Gene is inspired by par with modern evolutionary science than was Hamilton’s (1964a, 1964b) work on mathemati- human SB. EP also comprises the cognitive ap- cal models explaining the genetics of social be- proach, and although many cognitive theoreti- haviour. However Dawkins objects to Wilson’s cians do not accept the evolutionary, adaptation- prediction that ethology will be “cannibalized ist approach, their description of mind is com- by” SB (Wilson, 1975, p. 6). The SB epoch patible with evolutionary theory. seems to have passed, at least as the mainstream Is EP able to generate new theories and research program for the evolutionary study of insights about Human Nature? This question will Human Nature. be addressed throughout this article; from the The political issues that flared due to more rigorous, mature implementation of evolu- Wilson’s work centred on issues such as the ge- tionary principles compared to human SB, via netic argument for social status, the argument the rephrasing of mainstream cognitive theory, to being that social status is controlled by the heri- the application of the same theory in understand- table, individual differences of genetic makeup. ing normal personality, personality disorders and It is thus perceived as an argument for genetic psychopathology. determinism (Rose, Lewontin & Kamin, 1984; Does EP have the potential to unite the Bateson, 1986). It also inspired theoretical work science of psychology in a new theoretical para- on evolutionary and genetic issues, providing digm (Buss, 1995a, 1995b; La Cerra & Kurzban, scientific arguments against the perceived strain 1995)? This is a stronger form of the question of evolutionary and genetic theory promoted posed above, and must be considered a tall order. within SB thinking (Gould, 1977a, 1980; Le- This article will attempt to investigate the valid- wontin, 1979; Gould & Lewontin, 1979). This ity of Buss’ (1995a) claim that EP is a new para- demanded a response from theorists who did not digm for psychology, based on its ability to inte- identify with the charges of genetic determinism grate psychological traditions. (Dawkins, 1976/1989, 1982, 1986; Bateson, The three introductory quotations share a 1986). focus on the evolutionary basis of all things liv- This has caused a schism within evolu- ing, and their characters; including psychologi- tionary theory between the Modern Synthesis cal. This article will attempt to evaluate this and Pluralist Theory (Eldredge, 1995; Gould, stance, through an exposition of EP. 1983, 1993, 1997a, 1997b). It may seem however that the schism is more of a reality from the II. Antecedents: The Rise and Fall of Human So- perspective of the social sciences and humanities ciobiology (Selzer, 1993) than from biology proper (Mayr, 1983; Dawkins, 1986/1991; Dennett, 1995; With the publication of Sociobiology: The new Ridley, 1996; Hurst, 1998). synthesis in 1975, Wilson inspired and provoked In an evaluation of the academic and sci- a debate on the ethics and politics of an evolu- entific value of SB, Ruse (1979, p. 214) con- tionary and gene-based view of Human Nature, cludes that: as well as inspiring and heralding a burst of theoretical and empirical work. Wilson (1975, p. 4) […] I am far from convinced that human defined SB as “the systematic study of the bio- [SB]s have yet made their case. What I logical basis of all social behavior.” Dawkins do plead is that their sins are not as grave (1979a) finds this definition neutral, on a par as their critics argue. Human [SB] should with sciences like geology and history, although be given the chance to prove its worth. If he doubts that the definition is correctly under- it cannot deliver on its promises it will stood by social scientists, due to “biological” collapse soon enough […]; but if it does being misunderstood as “genetic”, which is mis- prove viable, then its success could pay understood as being deterministic. Dawkins scientific dividends of the highest order. (1979a, p. 427) offers his own “slightly irrever- ent epitome […] ‘SB is the branch of ethology

Human Nature Review, Volume 2, 2002, 19 Human Nature Review 2 (2002) 17-61 Dawkins (1979a) does not disagree with this first place, rather he would use “behavioural conclusion, but also claims one has to listen to Darwinist” for both ethologists and SBs. Al- the criticism. Ruse (1987, p. 77) sticks to this though Dawkins is dubbed SB by many authors line of argument eight years later: (Rose et al. 1984; Kitcher, 1985; Dennett, 1995), he is theoretically opposed to many ideas often Human [SB] has far to go before it can associated with SB. In The Extended Phenotype claim to be as solid a science as quantum Dawkins (1982) provides what Bateson (1986, p. mechanics, or even molecular biology. 92) calls “the best rebuttal of genetic determin- But even in its present primitive state, it ism [he has] come across”, despite being de- commands our attention. The critical ar- scribed as the “archetypal biological determinist” rows fired against it fail to penetrate to (Rose et al., 1984, p. 292). He also discusses vital organs. As science, it bears full constraints on perfection, including time lag: promise of a vital new way of under- “the animal […] is very probably out of date, standing Human Nature. built under the influence of genes that were selected in some earlier era when conditions were This critique has rarely been aimed at animal SB, different.” (p. 35), and all but discards the value although Gould & Lewontin (1979, pp. 588-89) of the concept of inclusive fitness (pp. 179-94), also use research on mountain bluebirds to illus- the hallmark of SB. Inclusive fitness is a meas- trate poor adaptationist work. Most often, as in ure of the interaction between relatives on one the following quote by Kitcher (1985, p. 435), another’s fitness; that is reproductive success animal SB receives great praise, while human (Hamilton, 1964a). In addition he makes a point SB attracts academic flack: that SBs do not appreciate the fact that memes do not by definition enhance inclusive fitness, [SB] has two faces. One looks toward the that they indeed are “selfish”, and may be mal- social behavior of nonhuman animals. adaptive for the individual’s fitness. Memes The eyes are carefully focused, the lips (Dawkins, 1976/1989, 1982, 1993; Dennett, pursed judiciously. Utterances are made 1995) are imitated ideas or replicating units of only with caution. The other face is al- culture. As such they are cognitive phenomena, most hidden behind a megaphone. With although Dawkins (1976/1989) introduces them great excitement, pronouncements about merely to illustrate the general principle of repli- Human Nature blare forth. cators (e.g. genes). Dawkins (1981) questions the behaviouristic language of ethology, wondering Holcomb (1993, p. 7) claims: “Evolutionary bi- whether a more subjective, awareness-oriented ology has long been an established science, and perspective might not be beneficial; a similar animal [SB] is now an established science, view is expressed by Dennett (1983; see also whereas human [SB] is not.” This statement may Dawkins, 1983). All in all a theoretical devel- seem premature in a chapter that intends to pro- opment, which has been driven by his gene eye vide the tools for the assessment of an emerging perspective, that maps neatly onto the later theo- science. How may one explain this difference in retical shift from human SB to EP. epistemological value, apart from through an in- Symons (1992) elaborates the difference grown reluctance to admit that man is an animal, between adaptiveness and adaptation to describe or that we should have evolved? In other words, the difference between EPs versus some human what is the scientific fault of human SB? SBs. According to Symons (1992, p. 146) these Dawkins (1979a, 1981, 1982, 1986) ar- SBs are those “evolution-minded scholars who gues forcefully against genetic determinism. seek to construct a psychologically agnostic sci- Dawkins (1979a) finds the understanding of “bi- ence of human behavior based on the hypothesis ology” as “genetic” to be a social scientist’s that human beings are reproduction (or inclusive misunderstanding, and seems to prefer the label fitness) maximizers.” Adaptiveness is what en- “ethologist”. Dawkins (1986) repeats these hances survival and reproduction, and is con- themes, pointing out that he cannot see any rea- cerned with the present (Symons, 1992; Betzig, son for coining the word “sociobiology” in the 1998). An adaptation, on the other hand, is the

Human Nature Review, Volume 2, 2002, 20 Human Nature Review 2 (2002) 17-61 result of what selection produced through evolu- ting the crucial aspect of adaptation (Mayr, tionary history, which served a certain function 1978). The theoretical transition from Sociobiol- with greater adaptiveness than other available ogy and Psychology (Crawford, Smith & Krebs, genetic variations could. Though it is an adapta- 1987) - via Crawford & Anderson’s (1989) envi- tion, it may no longer be adaptive, due to time ronmental SB - to Handbook of Evolutionary lag, where the environment has changed faster Psychology (Crawford & Krebs, 1998) docu- than the adaptations (Dawkins, 1982). Symons ments the influence of EP on the evolutionary (1992, p. 150) refers to a personal communica- approach to psychology, as well as how the sci- tion, where Tooby notes that “the study of adap- entific faults of SB have been rectified. tiveness merely draws metaphorical inspiration My conclusion is that Dennett (1995, p from Darwinism, whereas the study of adapta- 488) in describing EP merely as “the marriage of tion is Darwinian” (Italics in original). Adap- SB and cognitive psychology”, commits an over- tiveness reasoning is caused by a bias for “re- simplification that does injustice to the matured production-mindedness”, which follows from approach of EP over SB. If SB, as an evolution- exclusive commitment to inclusive fitness (all ary behaviourism, had only been caught up by behaviour will maximise reproductive success). the cognitive revolution (Sperry, 1993), it could Symons (1992, p 156) conclusion is that the ad- still focus on adaptiveness over adaptation, on aptations are psychological, and therefore “A individual genetic differences rather than univer- science of human behavior cannot be simultane- sal Human Nature, and the major critique of SB ously psychological agnostic and genuinely would be sustained. EP is inspired by the theo- Darwinian.” Cosmides & Tooby (1987) provided retical work of Dawkins (1976/1989, 1982, the missing link between the evolutionary proc- 1986/1991) and Williams (1966, 1985), more ess and manifest behaviour: the mental mecha- than that of Wilson (1975) and his followers. nism or psychological adaptation. Behaviour Thus the attacks on adaptationism by authors does not evolve; believing so would be reifying like Gould and Lewontin have not toppled the behaviour. Evolution takes place between genes project that Darwin (1859/1996) predicted; (Dawkins, 1976/1989) and combinations of rather they have acted like selection forces hon- genes. Genes code proteins, and proteins build ing the evolutionary theory of their opponents. structures. The mind consists of such structures This look at the evolution of EP from SB processing environmental information according through a selection for an emphasis on adapta- to rules that caused them to be selected for tions, has introduced a few theoretical points of (Darwinian algorithms, Cosmides & Tooby, debate that will be elaborated in the following 1987). The output these adaptations produce is pages, as well as prepare the ground for a de- behaviour. Evolutionary theory predicts behav- scription of EP. ioural variation due to varying environmental input (Cosmides & Tooby, 1987), but the III. Evolutionary Psychology: Describing and mechanisms designed by natural selection – ad- Discussing the Theory aptations – will comprise a universal human nature (Tooby & Cosmides, 1990a). With the arti- EP is an emerging, important new theoretical cle The Future of Sociobiology: Counting Babies paradigm of psychology, claims Buss (1995a), or Studying Proximate Mechanisms Crawford which main axioms are that mind consists of an (1993) turned the table on SB by questioning the array of evolved mental mechanisms, and that use of inclusive fitness (“counting babies”) and these mechanisms are functional, species- advocating cognitive methods in the study of ad- specific, task-specific adaptations, which process aptations of animal psychology. contextual information in order to solve proxi- The SB approach to psychology was be- mate and ultimate-level problems of genetic rep- haviour oriented (Crawford, 1987), reductionist lication. These adaptations may be discovered in its approach to defining evolution as changes through functional computational analysis using in allele frequencies over time (Mayr, 1978, p. available models of our hominid past and general 45; Noonan, 1987, p. 34), and focused on indi- principles of evolution. EP aspires to become an vidual differences (Crawford, 1987), thus omit- integrative meta-theory, able to connect the em-

Human Nature Review, Volume 2, 2002, 21 Human Nature Review 2 (2002) 17-61 pirical findings and mini-theories of psychologi- dominant Standard Social Science Model cal science. (SSSM) a thorough attack on the notion of Hu- This section attempt to describe and dis- man Nature as non-existent. They claim that the cuss central elements of the theory and its SSSM rests upon several defects, but focus on method of scientific examination of Human Na- three clusters. First, “the central logic of the ture, focusing especially on the theoretical work SSSM rests on naïve and erroneous concepts of Leda Cosmides and John Tooby. drawn from outmoded theories of development” (Tooby & Cosmides, 1992, p. 33). They exem- III.I. Models of Mind plify this by pointing out that as (other) physical adult traits do not need to be present at birth, nei- “There is no such thing as a ‘general problem ther do features of adult mental organisation solver’ because there is no such thing as a gen- need to be explained as the result of sociocul- eral problem” claims Symons (1992, p. 142). tural influence; they may have developed, like Dennett (1995, p. 491) begs to differ; writing the complex physical (brain) structures they are. this off as a “luscious slogan”. He supports his Second, “the SSSM rests on a faulty analysis of opinion by referring to Williams’ (1966) classic nature-nurture issues” (Tooby & Cosmides, work on adaptation, which is the major source of 1992, p. 33). The main fault is the dichotomy of EP on the nature of adaptations, and this is not biological and environmental factors operating in an unsubstantial challenge. Williams (1966, p. a zero-sum relationship (the more of one, the less 86) writes “A precise adaptation might require of the other), when the truth is that “environmen- more genetic information than one that would talist claims necessarily require the existence of give a blanket coverage to a broad category of a rich, evolved cognitive architecture” (Tooby & ecological demand.” It is thus more expensive, in Cosmides, 1992, p. 34, see also pp. 21-22; evolutionary coinage, and therefore less likely to Pinker, 1997a). Needless to say; anything arise. Both Dennett and Williams use the exam- evolved is biological. Thirdly, “[The SSSM] re- ple of wounds coming in all shapes and sizes, quires an impossible psychology” (Tooby & but the adaptation, whose function is wound Cosmides, 1992, p. 34). They claim that the find- healing, heals them all. Dennett (1995, p. 491) ings of important areas of research support their concludes that: “How general any cognitive conclusion: “A psychological architecture that mechanism is, or can be made to be through cul- consisted of nothing but equipotential, general- tural enhancement, is always an open empirical purpose, content-independent, or content-free question”, and of course this is true. One might mechanisms could not successfully perform the draw attention to the fact that Symons is con- tasks the human mind is known to perform” trasting general problem solvers to more specific (Tooby & Cosmides, 1992, p. 34). The result of problem solvers. In that respect Dennett’s criti- the SSSM is lack of communicability between cism seems too stringent, as the healing mecha- the social and natural sciences, due to an accep- nism he describes does not do anything but heal tance of a core dualism (Tooby & Cosmides, what is recognised as wounds and is therefore 1992). quite specific. If AI has any obvious value to the sci- Symons statement, slogan or not, draws ence of Psychology, it must be as an active tester attention to two major axioms of EP: the mecha- of models of mind. One lesson that EP has nistic, functional model of mind, inspired by learned is the need for a computational theory of work within Artificial Intelligence (AI), by al- mind (Cosmides & Tooby, 1994a, 1995). Pinker luding to Herbert Simon’s General Problem (1997a) provides the most elaborate defence of Solver, and the modular, species-specific, do- the computational theory of mind, and claims: main-specific, mental mechanism model of mind, “The proper label for the study of the mind in- as opposed to a model of mind that is described formed by computers is not Artificial Intelli- as domain-general (Buss, 1995a; Symons, 1992) gence but Natural Computation” (p. 83). or Lockean, empiricist or instructionalist (Gaz- When attempting to build machines that zaniga, 1992). Tooby & Cosmides (1992) offer could “see” several problems were encountered. in their critique of what they perceive as the Among these was the problem of inverse optics

Human Nature Review, Volume 2, 2002, 22 Human Nature Review 2 (2002) 17-61 (Poggio, 1984; Pinker 1997a); how can one, processes being modular too (Cosmides & starting with the retinal image, compute the Tooby, 1994a). qualities of what we see. Pinker (1997a, p. 28) This specially modified version of Fo- explains this paradox with the example of multi- dor’s model of mind is what EP adopts, but al- plication: “Just as it is easy to multiply some ways with the note that these modules are adap- numbers and announce the product but impossi- tations (Cosmides & Tooby, 1995). In fact, it is ble to take a product and announce the numbers because they are adaptations that the modular that were multiplied to get it, optics is easy but model of mind is co-opted (Cosmides & Tooby, inverse optics impossible”. The only way to 1994a, 1994b, 1995). solve the problem is to provide the “computer” with a set of algorithms that contain constraints III.II. The Functionality and Design of Adapta- on the possibilities. The result being that the tions tabula rasa view of mind is theoretically impossible. We need an innate representation of the Adaptations are the evolved solutions to prob- world, in the form of specific algorithmic rules lems encountered consistently through periods of of information processing, to be able to compute evolutionary history, designed through the natu- reality. This is called the frame problem; the an- ral selection of available genetic variation, which swer is a non-content-free mind, and as different in the process will tend to be reduced. Thus hu- problems need different content the mind must man adaptations make up Human Nature, and consist of several domain-specific computing are universal to almost all humans (Tooby & mechanisms, or modules (Fodor, 1983, 1985). Cosmides, 1990a), degenerative mutations or Fodor (1985) describes the difference be- non-nurturing environments causing the missing tween modularity and interactions or global cases. Williams (1966) tied adaptations to non- views of cognitive architecture, and argues that chance function, “effect […] produced by de- there is no continuity from perception to cogni- sign” (p, 261), where there are two functions: tion. Perception is the result of “integrations […] proximate (what does the adaptation cause here performed by computational systems that are and now) and ultimate, which Williams (1966, p. informationally encapsulated” (Fodor, 1985, p. 252) defined as Hamilton’s (1964a) “inclusive 3). These encapsulated computational systems fitness” (See Dawkins, 1979b, 1982). Adapta- are “modules”, where “modules” are defined as tions are thus functional by definition. Adapta- “an inference-making mechanism whose access tions designed by natural selection are the com- to background information is constrained by mon explanation of any functional, complex de- general features of cognitive architecture, hence sign (Williams, 1966; see also Dawkins, relatively rigidly and relatively constrained” 1986/1991; Dennett, 1995); although orthodoxy (Fodor, 1985, p. 3). Pinker (1997a, p. 31) prefers has been challenged (Gould, 1983, 1991, 1993, Chomsky’s metaphor of “mental organ”, rather 1997; Gould & Lewontin, 1979; Gould & Vrba, than module, in order to focus more clearly on 1982; Lewontin, 1979). I will return to this de- the organic aspects of the mind’s information bate later. Presently it will suffice to state that computing “modules”; they are not as encapsu- EP (Buss, 1995a, 1995b; Buss et al, 1998; Cos- lated as Fodor (1985) would have them. Another mides & Tooby 1987, 1994a, 1994b, 1995, 1997; point worth making is that EPs do not accept Fo- Gazzaniga, 1992, 1995b; Symons, 1987, 1992; dor’s (1985) insistence that there is no continuity Tooby & Cosmides 1990a, 1990b, 1995; Pinker, between perception (modular) and central or 1994, 1997a, 1997b) is committed to the adapta- higher cognitive processes, such as “thought” tionist program (Mayr, 1983). and “problem solving” (Cosmides & Tooby, An adaptation is recognised by evidence 1994b, 1995;Gallistel, 1995; Gallistel & Cheng, of special design (Williams, 1966), which is a 1985; Sperber, 1994). These, Fodor (1985, p. 4) systematic interaction between environmental claims, are “global” and “everything perception input and phenotypic output, where adaptiveness is not”; which in this respect means non- (inclusive fitness) is supposed to be to the ances- modular. EP is theoretically committed to these tral environment to which it evolved, not

Human Nature Review, Volume 2, 2002, 23 Human Nature Review 2 (2002) 17-61 necessarily current conditions. EP is interested in a certain kind of com- Tooby & Cosmides (1995, p. 1192) offer plex design, and although an evolved design is a the formal properties of an adaptation in figure 1. genetic design, which causes the design of certain proteins, which in turn build neurological Figure 1: The formal properties of an adaptation structure, EP is interested in the level of cognitive structure. This is the level of what may be 1. A Cross-generationally recurring set of charac- called cognitive programs, mental organs, mod- teristic of the phenotype, 2. that is reliably manufactured over the devel- ules or Darwinian algorithms (Cosmides & opmental life history of the organism Tooby, 1987). 3. according to instructions contained in its genetic Inspired by the Darwinian Functionalism specification, of William James, Cosmides and Tooby (1987, 4. in interaction with stable and recurring features 1994a, 1995) have focused on the need for a of the environment (i.e., it reliably develops normally when exposed to normal ontogenetic environments), functional analysis of psychological phenomena. 5. whose genetic basis became established and In order to do this, they advocate applying organized in the species (or population) over evolution- Marr’s (1982) computational model. ary time, because Marr (1982, p. 24-27) described three 6. the set of characteristics systematically inter- levels at which any information processing acted with stable and recurring features of the environment (the “adaptive problem”), mechanism must be understood (Table 1). 7. in a way that systematically promoted the propagation of the genetic basis of the set of characteris- Table 1 tics better than the alternative designs existing in the population during the period of selection. This promotion Three levels at which any machine carrying out virtually always takes place through enhancing either the an information processing task must be under- reproduction of the individual bearing the set of charac- stood teristics, or the reproduction of the relatives of that individual. Computational Representation Hardware im-

It is important to note that the reproduction of theory and algorithm plementation “the individual bearing the set of characteris- What is the goal How can this How can the tics”, in point 4) of the figure (i.e. replication of of the computa- computational representation the genes “for” the characteristic) is quite suffi- tion, why is it theory be imple- and algorithm be appropriate, and mented? In par- realized physi- cient. One ought to, in order to be precise, add what is the logic ticular, what is cally? that “the reproduction of the relatives of that in- of the strategy the representation dividual” has to include only, or to a greater de- by which it can for the input and gree”, those relatives that share the genes for the be carried out? output, and what characteristic, if one shall be true to Dawkins’ is the algorithm for the transfor- (1982). This is where the difference between mation? Dawkins’ gene-perspective and Hamilton’s inclusive fitness becomes clear. Kin selection only From Marr, 1982, p. 25. works if genes for kin selection exist in those who survive due to the “altruistic” act of the Cosmides & Tooby (1994a, 1995) add to this bearer of the kin selection genes. If not the genes that in the case of evolutionary biology “expla- for kin selection will vanish as soon as they ap- nations at the level of the computational theory pear. Thus genetic similarity (or high likelihood are called ultimate-level explanations. Explana- of such) must specify kin. Also “normal” onto- tions at the level of representation and algorithm, genetic environments, ought to have been speci- or at the level of hardware implementations, are fied. My suggestion is that one defines “normal” called proximate-level explanations” (Cosmides in this respect as “an adequate approximation of & Tooby, p. 45; Cosmides & Tooby, 1995, p. the EEA” where the “EEA” will be specified be- 1200). The ultimate-level explanations are ge- low (III.III), and “adequate” means “recognis- netic reproduction, or fitness, explanations, able to the developing adaptation.” which will be governed by the theory of natural selection and derivatives (Darwin, 1859/1996;

Human Nature Review, Volume 2, 2002, 24 Human Nature Review 2 (2002) 17-61 Hamilton, 1964a, 1964b; Williams, 1966; identified, it becomes straightforward to develop Dawkins, 1976/ 1989, 1982, 1986/1991; Trivers clinical tests that will target its neural basis” 1971, 1972). The functional mental mechanisms (Cosmides & Tooby, 1995, p. 46). that these theories predict limits the hypothesis Cosmides and Tooby (1995, p. 1209) of- space for the scientist to search; some mecha- fer this conclusion in Gazzaniga’s (1995) The nisms become more likely - other mechanisms Cognitive Neurosciences: would not have been possible to develop. In arguing for the value of a computa- Through the computational theory, evolu- tional theory Marr (1982) claimed that tionary biology allows the matching of “[a]lthough algorithms and mechanisms are em- algorithm to adaptive problem: Evolu- pirically more accessible, it is the top level, the tionary biology defines information- level of computational theory, which is critically processing problems that the mind must important from an information-processing point be able to solve, and the task of cognitive of view” (p. 27). For EP this level has been neuroscience is to uncover the nature of elaborated: “Modern evolutionary biology con- the algorithms that solve them. The stitutes, in effect, a foundational organism design brain’s microcircuitry was designed to theory, whose principles can be used to fit to- implement these algorithms, so a map of gether research findings into coherent models of their cognitive structure can be used to specific cognitive and neural mechanisms” bring order out of chaos at the neural (Tooby & Cosmides, 1995, p. 1186). Other areas level. of psychological research lack such a guiding computational theory. The reason why the com- Put more simply: “To figure out how the mind putational theory is critical is according to Marr works, cognitive neuroscientists will need to (1982, p. 27) that “an algorithm is likely to be know what problems our cognitive and neural understood more readily by understanding the mechanisms were designed to solve” (Cosmides nature of the problem being solved than by ex- & Tooby, 1995, p. 1201.) amining the mechanism (and the hardware) in which it is embodied.” Cosmides & Tooby III.III The Environment of Evolutionary Adapt- (1995, p. 1201; 1994, p. 46) argue against the edness: Using Evolutionary Theory and Strategic idea that empirical findings of “low-level” neu- Modelling to Guide Research on Adaptations roscience “will place strong constraints on theory formation at the cognitive level.” They doubt Stanislaw (1991) claims that one reason why all that the properties of neurophysiology will lead psychologists are not Darwinians, i.e. why evo- to the discovery of cognitive programs, due to lutionary theory is not a viable foundation for the fact that “[t]he same basic neural tissue em- psychologists, is the lack of independent (of psy- bodies all of these programs” (Cosmides & chological findings) knowledge about ancestral Tooby, 1995, p. 1201, italics in original). conditions. This knowledge is demanded if one Cosmides & Tooby (1994a, p. 46) claim: “For shall be able to infer what problems needed to be this reason a computational theory of function is solved, and predict what mental mechanisms we not an explanatory luxury. It is an essential tool may have developed to solve them (Tooby & for discovery in the cognitive and neural sci- DeVore, 1987; Tooby & Cosmides, 1990b). ences.” This it not to say that they believe that Crawford & Anderson (1991) reply that rigorous the theory of function will specify an algorithm’s evolutionary psychologists need not resort to design, but it “reduces the number of possibili- tautology, due to an abundance of independent ties to an empirically manageable number ” “[a]rchaeological and anthropological evidence (Cosmides & Tooby, 1994a, p. 46). This is due about the life of our ancestors” (p. 249). They do to a restriction of functions to those that were not refer any source, e.g. Tooby & Devore adaptive in our evolutionary past, and that there (1987), however, and as that analysis is the ma- are a limited number of programs that may solve jor reference on the adaptationist EP approach to any of the adaptive problems. On an optimistic this evidence, Stanislaw’s fears were probably note they claim “once [a] program has been not properly put to rest.

Human Nature Review, Volume 2, 2002, 25 Human Nature Review 2 (2002) 17-61 Tooby & DeVore (1987) present the be- Dawkins, 1979b), parental investment (Trivers, ginnings of an adaptationist conceptual model of 1972), reciprocal altruism (Trivers, 1971), and hominid behavioural evolution. They criticise game theory (Maynard Smith, 1979; Axelrod, the use of existing referential models, stressing 1984), amongst others. Tooby & DeVore (1987, the need for a conceptual model to evaluate any p. 191-200) provide a list of 25 heuristic guide- referential model (studying a real phenomenon lines for inference, and illustrate how these, even in the place of another real phenomenon less in their preliminary form, may be used to pro- readily studied). Tooby & DeVore (1987) point ductively evaluate current models of human be- out that “the use of such models is arbitrary” (p. havioural evolution. Tooby & DeVore’s hope is 186), due to the lack of a validated conceptual “that the application of evolutionary principles model for selecting a living species as a parallel will constrain the range of possible hominid to an extinct species. They also claim that due to traits” (p.190), where likely parameters for the the referential perspective not having established model will be provided by the investigation of any conceptual model for differences between “patterns of primate homology”, “characteristics hominids and the arbitrarily selected referential present in modern humans”, “the paleontological model species, two problems arise. First, an ex- [and] archaeological record” and “knowledge of aggerated interest in the evolutionary stage when ancient habitats.” differences between model and the extinct homi- The conclusion I draw from this is that nid species were supposedly minimal. This focus Stanislaw (1991) made an important challenge, sheds little light on what events caused our an- although one recognised and addressed by EP. cestral line to evolve into humans, while other Also, though Crawford & Anderson (1991) are lines went extinct or evolved into e.g. apes. Sec- correct that information does exist, “abundance” ond, what seems to be a result of the first, “simi- might not be the correct term. In addition, by not larities are emphasized at the expense of differ- specifying by what criteria they were evaluating ences” (p. 187). Explaining human behavioural the information from their archaeological and evolution is to explain the design of what is anthropological sources they were not as strin- uniquely human, our species typical adaptations, gent as made possible by Tooby & DeVore and “one cannot invoke the features species have (1987). Any scientific investigation into possible in common to explain their differences” (p. 187). mental mechanisms would have to be founded Due to these limitations of referential models, on an analysis of what mechanisms were needed Tooby & DeVore advocate that one discards to solve what problems, as well as what mecha- them. Notice the importance placed on the speci- nisms could possibly evolve or were likely to ficity of human traits; a basic axiom of EP. evolve. Tooby & DeVore (1987) introduce the With a strategic model of the past one term “strategic modelling” to describe the forma- may explain the present (Tooby & Cosmides, tion of conceptual models of primate and homi- 1990b). Tooby & Cosmides (1990b) call the nid behaviour building upon the comprehension “past” the Environment of Evolutionary Adapt- of: “1) the genes as the unit of selection, and 2) edness (EEA). The EEA is defined as “a statisti- animals as shaped to behave as strategists pro- cal composite of the adaptation-relevant proper- moting their inclusive fitness” (p. 189). They call ties of the ancestral environments encountered the recognition that the gene is the unit of selec- by members of ancestral populations, weighted tion, “a central achievement of modern evolu- by their frequency and fitness-consequences” (p. tionary biology” (p, 189), of which EP has 386-7). This does not make the EEA a certain played a central part (Cosmides & Tooby, 1981). habitat, instead it is the “complex statistical To construct a conceptual strategic model, one composite of structurally described contingen- must be able to formulate general (in both time cies of selection”; and these contingencies may and species) principles of evolution designing vary (p. 387). Different adaptations and different both current and past adaptations. Such princi- periods of evolutionary change will demand the ples may include evolutionary stable strategies specification of specific EEA’s. The EEA for a (Dawkins, 1976/1989, 1980; Maynard Smith, specific species’ collection of adaptations (which 1979), kin selection (Hamilton, 1964a, 1964b, may be used as a definition of species, within

Human Nature Review, Volume 2, 2002, 26 Human Nature Review 2 (2002) 17-61 EP) “can be taken to refer to the statistically limitations to and interact with adaptations weighted composite of the environmental prop- (Maynard Smith, 1986). Rules of development erties of the most recent segment of a species’ also make one aware of the need for a descrip- evolution that encompasses the period during tion of an adequate, stimulating, or repressing which it’s modern collection of adaptations as- environment in order to explain the variance of sumed their present form.” For human evolution development of any structure. The lack of certain the Pleistocene period (which lasted from 1,6 ingredients as well as the addition of certain tera- million years ago till 10 thousand years ago) ful- togenes (Greek for “monster makers”) will cause fils these requirements for most adaptations, and the disruption of the usual development, and like is often used within EP as equivalent to EEA. mutations, most of these new forms will be The co-ordination of the problem-setting harmful to the organism. One will expect most environment and the problem-solving adaptation adaptations to develop adequately, in an ade- designed through natural selection, cause the quate environment, and vice versa. close fit between organism and environment. An adaptation will be designed to solve This fit need not be perfect, adaptations are not problems that were invariant in the EEA; it is necessary “optimal”. Dawkins (1982, p. 46) de- also designed to develop in an environment simi- scribes them as “meliorizing”; that is being bet- lar to the EEA. Thus, one may discover that ad- ter than other competing designs. Any theory of aptations cause maladaptive behaviour under en- evolution must explain the existence of these ad- vironmental conditions that vary too much from aptations, and this was the main objective of the EEA. The empirical illustration provided by Darwin’s theory (Ridley, 1996). As such present Tooby & Cosmides (1990b) describes the adaptations are records of the past (Tooby & Westermarck mechanism for avoiding incest. Cosmides, 1990b, p 389). Some call this fossil- This adaptation consists of “a mechanism that ised behaviour or call humans living fossils ‘judges relatedness’ for the purpose of incest (Buss, 1995a, p.10). avoidance […] by the duration of intimate exposure in the first years of life” (p. 385) and uses III.IV The Present Ontogenetic Environment and this information to decrease sexual interest. This Rules of Development mechanism will be adaptive and functional in preventing inbreeding among siblings, but was The past created us body and mind, to para- found to be “maladaptive”, though still function- phrase Dawkins (1976/1989, p. 20 and p. 271) ing, amongst those non-relations who grew up in correctly. But, unlike what those who have read kibbutz-crèches. There was no danger of in- only Rose et al.’s (1984, p.287) misquote of breeding, but the mechanism could not tell that Dawkins (See Oyama, 1991, p. 40) might be- the environment had changed. lieve, this does not mean that the past or “our Tooby & Cosmides (1990b) advise that genes control us”. The present environment has one describes the environment in terms of two two functions in evolutionary thinking: phyloge- different features. First, one must provide a de- netically speaking it is the selection forces for scription of “the state of those features that must the present generation (“a single increment in the be stably present for the organism’s adaptations EEA of future generations” [Tooby & Cosmides, to reliably develop” (p. 385), which must be an 1990, p. 388]) and ontogenetically speaking it is adequate approximation of the EEA. Second, the input for genetic developmental programs. one must describe “the state of those features “[T]he organism blindly executes the programs it that the organism’s adaptive procedures take as inherits, and the ontogenetic conditions it en- input and process into structured phenotypic counters serve as parametric inputs to these pro- output” (p. 385). This may be “anything that de- grams” (Tooby & Cosmides, 1990, p. 388). The velopmental programs contingently respond to”, word “blindly” is misleading; it is the environ- including “information processed by cognitive ment that the programs “see” when running, and mechanisms”. must “see” in order to run. Buss (1995a, p. 11) claims, reacting to Adaptationist theory is aware of the in- charges that EP advocates “rigid, genetically influence of rules of development; these set certain flexible behavior patterns”, that “there are few

Human Nature Review, Volume 2, 2002, 27 Human Nature Review 2 (2002) 17-61 other perspectives within psychology that place ing solutions, one will get selection and adapta- greater emphasis on a detailed and complex tion. The design of these functional structures treatment of environmental, situational and con- takes time, and once designed will very likely textual factors.” This may seem surprising to have used up the genetic variance. Any new certain environmentally oriented disciplines, but variance (mutations) is likely to be harmful, as it the message is probably that EP is not the con- is “random” and can be compared to noise. Thus textually naïve discipline that earlier evolution- adaptations will have near zero heritability, de- ary approaches have been criticised for being. fined by population genetics as the lack of phe- Buss (1995a) describes, in addition to the notypic difference among individuals that can be historical selective context (the phylogenetic attributed to genetic differences, and will be context), two ontogenetic context-analyses. First, shared by most members of the species - defin- analyses of ontogenetic experience early in life ing the species. However, due to the design tak- may decide the track of development later in life. ing time, and the need for the ontogenetic envi- The early experience provides the child with in- ronment to provide the adaptations with the information about what strategy to follow as an formation they process and need to develop, adult and specific contextual input that selects there may be a lack of adaptiveness. This lag is strategy choice. Second, analyses on ontogenetic obviously an important factor for humans, given experience “sets differing thresholds on species- the rapid change of our environment. Still, what typical psychological mechanisms” (p. 11). On- define our nature are our evolved mental mecha- togenetic context varies both with sex and cul- nisms, operating with our present environmental ture. The third level of analysis Buss (1995a) information. describes is the “immediate situational inputs This is a controversial view, and it is to that activate the operation of particular psycho- the discussion of the centrality of adaptations to logical mechanisms” (p.11, italics in original). Human Nature we now turn.

III.V. Summary & Conclusions IV. The Adaptationist Controversy

Having presented and discussed most of the fea- So far, Adaptationism has been taken at face tures of an adaptationist analysis, this may be value, but as quite a few renowned theoreticians summed up in five “nested but distinct levels” have claimed that this approach to the study of (Tooby & Cosmides, 1990b, p. 384-385): 1) Human Nature is at fault, a discussion of the Models and principles of evolutionary biology. Adaptationist program is necessary. If the 2) A specification of the EEA (Tooby & “Adaptationist program” (Gould & Lewontin DeVore, 1987; Tooby & Cosmides, 1990b), and 1979; Lewontin, 1979; Mayr, 1983; Williams the formulation of computational theories (Marr, 1985) is intellectually “bankrupt” this will effec- 1982; Cosmides & Tooby, 1994a, 1995). 3) tively tumble EP’s theoretical foundation. Through an implementation of level 1) and 2) The conflicting stances have been de- one may discover, investigate, describe and ana- scribed in many ways: Adaptationists are often lyse functionally the species’ adaptations. 4) A also called neo-Darwinists, ultra-Darwinists, description of the present, ontogenetic environ- panselectionists or even grouped as SBs, though ment. 5) An integration of the findings of level most would claim that they simply adhere to the 3) and 4) into an individual’s normative devel- Modern Synthetic Theory (Mayr, 1978), which opmental trajectory. is mainstream Evolutionary Theory (Ridley, Human Nature may be defined as our 1996). Eldredge (1995) lists George C. Williams, collection of adaptations. A rigorous investiga- John Maynard Smith and Richard Dawkins as tion of human psychology is guided by the the most central figures on this side. The oppos- forces that designed these adaptations; the prin- ing side is easier to define by referring to persons ciples of evolution. These principles are envi- and ideas, Eldredge (1995) lists Stephen Jay ronmentally and genetically dependent; given an Gould, Elisabeth Vrba and himself, on this side. environmental problem and the genetic variance One may add Richard Lewontin. The ideas are to allow for a solution that is better than compet- Punctuated Equilibrium, Spandrels, Exaptations,

Human Nature Review, Volume 2, 2002, 28 Human Nature Review 2 (2002) 17-61 Contingency and Constraint. They often choose practice, as opposed to the Continental European the label Pluralists, invoking Darwin’s 6th edition tradition. This is how the critique of adaptation- of Origin. Eldredge (1995) offers an extra guide- ism will be understood in this section, as the line to understanding the differences; adaptation- adaptiveness stance has been dealt with previ- ists are often geneticists, while pluralists are ously (section II). Lewontin (1979) makes a more likely palaeontologists. This naturally more explicit attack on SB, but uses the broader gives the two sides quite different perspectives faulty adaptationist strain of the last 25 years (as on the same process; the one being here and now opposed to the last four, since Wilson published process-oriented, the latter being committed to Sociobiology in 1975), yet again including main- geological time, structure and historical analysis. stream evolutionary theory in the attack. Le- The fact that the Modern Synthetic theory is his- wontin (1979) defines the adaptationist program torically a genetic theory of evolution, may shed as the “approach to evolutionary studies which light on the paleontological resistance, at least as assumes without further proof that all aspects of well as different, more or less well formulated, the morphology, physiology and behavior of or- hypothetical political motives. Although the dif- ganisms are adaptive optimal solutions to prob- ferences between these theoretical camps en- lems” (p. 6). Mayr (1983), in defence of the compass several themes, I will focus on the con- adaptationist program, claims that these defini- troversy as it pertains to adaptationism. Many tions caricature adaptationism. Sober (1987), are familiar with the Gould & Eldredge (1977, discussing the different forces that influence 1993; Eldredge & Gould, 1972) critique of evolution (selection, mutation, genetic drift, and mainstream “phyletic gradualism”, but this pleiotropy), concludes that adaptationism is: theme has not yet become relevant to the evaluation of EP. It will therefore not be discussed The thesis that certain simple models are here. good predictive approximations. It does not deny that other forces were at work. IV.I. Adaptationism: The Panglossian Paradigm Nor should it pretend that there is an in- and Just So Stories telligible way to compare the magnitudes of all the factors that contribute to an Adaptationism is defined by Gould & Lewontin evolutionary outcome. Rather, adapta- (1979, p. 584-5) as the: tionism holds that the predictions that follow from simple selectional models, in notion [of] the near omnipotence of natu- which the true selection coefficients are ral selection in forging organic design recorded, would not be much perturbed and fashioning the best among possible by taking other factors into account. worlds. This programme regards natural selection as so powerful and the con- This is a more balanced account, as long as it straints upon it so few that direct produc- admits that adaptationists accept that other forces tion of adaptation through its operation are at work. If the selectional models in addition becomes the primary cause of nearly all are framed as asymptotic, that is as the perfect organic form, function, and behaviour. but highly unlikely model to test against, then the simplicity of the selectional models becomes This definition will easily attack an adaptiveness unproblematic. These definitions set the stage for approach, which is appropriate if the target is the discussion that follows. exclusively SB, the adaptiveness argument Gould & Lewontin (1979) use two liter- claiming that natural selection will always ary metaphors to characterise (or caricature) the maximise inclusive fitness, without constraint. adaptationist program. First, the Panglossian Not accepting the adaptiveness-position will be Paradigm, the perspective that all is for the best considered to “underestimate the power of natu- of all, named after Dr. Pangloss, the caricature of ral selection” (Betzig, 1998, p. 271). However, the philosopher Leibniz created by Voltaire this was perceived to be an attack on mainstream (1759/19) in his satirical work Candide. Second, English and American evolutionary theory and “story telling”, later dubbed “Just So Stories”

Human Nature Review, Volume 2, 2002, 29 Human Nature Review 2 (2002) 17-61 (Gould, 1980). A Just So story is the derogatory proper explanations among the substantial set of label awarded any overly simplistic, evidentially plausible pathways to any modern result” (Gould unfounded, account of phyletic history which & Lewontin, 1979, p. 588). This shows the focus caused the evolution of the adaptation consid- of the palaeontologist as much as that of the plu- ered. Both these metaphors are theory-of-science ralist. The idea is that if only the adaptationist attacks, implemented to posit the research thus approach could be falsified, other explanations labelled as unscientific. They are famous outside would be sought out. The continuous re- of biology proper (where they tend toward being formulation of “adaptationist stories” or func- considered more as infamous), and are easily tional hypotheses prevents this. Gould (1989) wielded against adaptationist accounts- whether has since then worked on historical contingency, the attacks are valid or not (Dennett, 1995, p. elaborating the effect chance events may have on 239). evolution. This might not be necessary beyond Just So stories (Gould, 1980) are named the constraints the adaptationists themselves are after Kipling’s (1902/1994) book of classic fa- aware of (Gould & Lewontin, 1979; Dawkins, bles describing e.g. How the Leopard Got His 1982; Maynard Smith, 1986; Mayr, 1983; Spots through Lamarckian-inheritance. The rea- Ridley, 1996). Holcomb (1996) addresses the son for choosing this label is that the book, in worry expressed (Gould & Lewontin,1979; offering simple, intuitive stories, is fictional and Gould, 1980) that when one at last “concocts ” a of no scientific worth, though Kipling’s hypothe- “plausible story”, a theory that makes sense of ses may be tested against the adaptationist, func- the data, using the adaptationist perspective one tional hypothesis (Williams, 1985). Gould & stops there. Holcomb (1996, p. 528) concludes Lewontin (1979) attack adaptationist storytel- that: ling, which is the evolutionary ecological and selectionist explanation provided to account for We cannot prove that the theoretical hy- observed functional behaviour, physiological pothesis is objectively correct in a sense process, or anatomical structure. Thus it predicts that is not an artifact of skilful mutual ad- what functions, or ecological interactions one justment. Given the failure of being able should expect (Williams, 1985). Gould & Le- to (inductively) justify or (deductively) wontin (1979, p.587) criticise the adaptationists falsify a theory, this is the best we can do for revising these stories when they are found […]. wanting: “the rejection of one adaptive story usually leads to its replacement by another, Ridley (1996, p. 364), a mainstream adaptation- rather than to a suspicion that a different kind of ist, is fully aware of the problem: explanation may be required.” This does not necessarily strike one as being a weakness. This method [of moving from one factor When a hypothesis is falsified, one changes to another, making analyses made purely one’s hypothesis, and usually one does so until in adaptationist terms], if carried far on finds one that is not falsified; as Dawkins enough, will almost inevitably find a fac- (1983, p. 361) puts it: “that is what science is all tor that predicts [the studied hypothetical about!” Dawkins (1983, p. 361) points out that “adaptation”] correctly. Eventually, by the untestable hypothesis is the “hypothesis of no chance, a relation will be found, if adaptive function at all”. This does not mean that enough other factors are studied. One this might not be the truth, merely that one can- will be found even if [the presumed adap- not test it. Gould & Lewontin object to the idea tation] is a neutral character. of explaining the reason and cause of function, and as such they are attacking the mainstream The major problem is, according Ridley (1996), science model, and not only SB. This is not only to be able to recognise adaptations, because due to their objection to natural selection and “[t]he methods of studying adaptations work adaptations being the most focused research well if we are studying an adaptation” (p. 364, guiding theory or principles: “The key to histori- italics in original). The cautionary note being cal research lies in devising criteria to identify that “[t]he evidence of history, although it may

Human Nature Review, Volume 2, 2002, 30 Human Nature Review 2 (2002) 17-61 encourage the study of adaptation, certainly does is optimally functional (this is either a strawman not prove that all characters are adaptations” (p. or an outdated perfectionist stance), by others as 365). Mayr (1983, p. 327) admits that “[t]he at- the asymptotic value one measures constraints or tack directed by Gould and Lewontin against un- selection forces against, not a theory to be con- supported adaptationist explanations […] is fully firmed or refuted (Dawkins, 1980; Maynard justified.” He goes on to point out that in his Smith 1983). Dawkins’ (1982) focus of melioris- opinion these are not supplied by modern evolu- ing systems seems to be very close to Gould’s tionists. Ridley’s (1996) modern adaptationist, (1993, 312) use of Panglossian, quoting Voltaire: and in no way perfectionist, claim is that “le meilleur des mondes possibles”. Although “[p]luralism is appropriate in the study of evolu- Dawkins’ focus is not on the best but on the bet- tion, not of adaptation” (p. 341) though ter design. Dawkins (1976/1989, 1980) even ar- “[a]daptations in nature are not perfect” (p. 349). gues that as long as designs are evolutionary sta- By calling the adaptationist program the ble they are selected for even when introducing Panglossian paradigm, Gould & Lewontin strategies, which from an engineering perspec- (1979) were perceived as attacking the Modern tive might be better. If it does not manage to dis- Synthetic theory. The Panglossian paradigm, or rupt the existing strategy’s stability it is ecologi- versions of it, have been offered several times cally, and thereafter evolutionary, the worse prior to Gould & Lewontin’s exaptation of Vol- strategy. One may reconsider the relevance of taire’s caricature of Leibniz: Dawkins (1983) the Panglossian paradigm attack; it is not the refers to a personal communication from John best of all possible solutions, but it may be a so- Maynard Smith, in which he recalls that J. B. S. lution all the same. Then again, bearing in mind Haldane used Pangloss to debunk group- Ridley’s (1996) warning, it may not be. The fact selection; Gould (1993) quotes William Bate- that this is mainstream adaptationism, renders son’s use of Pangloss in attacking early the Panglossian paradigm into a non-relevant panselectionism. Voltaire used the character attack. Pangloss to caricature the philosophy claiming Dennett (1995, p. 239) reveals the iden- that “this is the best of the possible worlds”, by tity of the anonymous critic (Dennett, 1983; see twisting it to claim “this is the best possible also Dawkins, 1983, p. 360) who had first intro- world” (Mayr, 1983, p. 327). Once one accepts duced him to Gould & Lewontin’s (1979) article constraints of any kind, the Panglossian para- which claimed to have shown adaptationism to digm is no longer valid. Adaptationists accept be “bankrupt” (Dennett, 1983, p. 351). The constraints; Mayr (1983, pp. 331-2) describes nonadaptationist was none other than Jerry Fo- several constraints “based in part on independent dor, the proponent of the modularity of mind. analysis”, and Dawkins (1982) spends a chapter Fodor’s claim, according to Dennett (1983, discussing constraints, noting (1983, p. 361) that 1995) was that Dennett’s intentional stance was “constraints on perfection are fascinating objects a logical continuation of adaptationism, and thus of study in their own right” (see also Ridley, also intellectually “bankrupt”. This was the im- 1996). Mayr (1983, p. 327) puts it this way: “Se- petus which caused Dennett (1983) to write his lection does not produce perfect genotypes, but it defence of the Panglossian paradigm, or adapta- favours the best which the numerous constraints tionism, and thereby the intentional stance. Den- upon it allow.” Mayr (1983) casts constraint-free nett counters Fodor’s criticism by casting Gould perfectionism as the pre-Darwinian natural theo- & Lewontin’s perceived nonadaptationism logian’s Weltanschauung; an omnipotent Creator (though the conclusion was “pluralism”) as a has no constraints, but does not accept that this is continuation of Skinner’s behaviourism, a com- the common view of modern evolutionary scien- mon target for both Dennett and Fodor. tists (see also Eldredge, 1983, for a similar Skinner’s (1983) reply is interesting as he analysis from the other side of the “high table” points out that both natural selection and operant [Eldredge, 1995]). conditioning are “examples of selection by con- The Panglossian paradigm is closely tied sequences”, though “they have features in com- to optimality theory, which is understood by mon just because they exemplify selection but some as the idea that an adaptation or organism otherwise represent different biological and so-

Human Nature Review, Volume 2, 2002, 31 Human Nature Review 2 (2002) 17-61 cial processes” (p. 377; see section V.III. for a not bare any inherent function. Dennett (1995) discussion of learning and EP). Lewontin’s broadly challenges the idea of nonadaptive struc- (1983) reply focuses on the open pluralistic pro- tures. He suggests that the architectural concept gram, and adaptation versus adaptationism, there of pendentive would be a more correct name (see being an important difference between accepting Gould, 1997c), and even claims that examples of other evolutionary mechanisms and denouncing spandrels that Gould & Lewontin (1979) sug- selection. gested no-one would propose as primary (i.e. the Dawkins (1983) in commenting on Den- reason for the design), may indeed be primary nett’s defence of adaptationism concludes that (See Gould & Lewontin, 1979, p.582-3; Gould, adaptationism never was in need of such a de- 1993, p. 334; Dennett, 1995, p. 274). It is not fence; it is a thriving science. The adaptationist necessary however to suppose that there do not program is defended by Mayr (1983), as the exist nonadaptive structures. Spandrels are de- mainstream functional inquiry of physiological fined and understood, within evolutionary the- and other biological phenomena. Williams ory, by Gould & Lewontin’s (1979) definition: (1985) defends the reductionist aspects and se- “necessary architectural by-products” (p. 147) cures the methodological value of adaptationism. and “architectural constraints” (p. 148). “De- Holcomb (1996) addresses EP specifically, and sign” or “structural” may substitute “architec- although he claims EP is not yet science (it is tural”. Spandrels are not designed by natural se- “protoscience”), using the label of Just So stories lection; rather they are the result of natural selec- to reduce scientific credibility is unfair compared tion operating within the constraints of the given to practice in other sciences. The practice Bauplan, the set, possible, pre-existing structure. dubbed “telling Just So stories” is the standard As Dennett (1995, p. 272) puts it “spandrels are scientific method of inference. Holcomb (1996) what remains of a wall once you punch an arch claims: “[EP] has progressed beyond telling just- through it.” Gould is most often structuralist in so stories. It has found a host of ingenious spe- his writings (Gould, 1987a), as one would expect cial techniques to test hypotheses about the adap- from a paleontological perspective; a fossil will, tive significance and proximate mechanisms of with greater ease, provide data on structure, behavior.” anatomy, rather than processes or function; There does not seem to be any reason to physiology and behaviour. The chin is offered as question the general scientific standard of evolu- a favourite example. It is not an independent tionary science (Holcomb, 1993, 1996; Mayr, structure; what we call “the chin” is the result of 1983; Ridley, 1996; Williams, 1985), or the sci- what is called neoteny, the principle of retaining entific standards of the adaptationist foundations “formerly juvenile characters by adult descen- of EP (Holcomb, 1996). dants […] produced by the retardation of somatic development” (Gould, 1977b, p. 483). The two IV.II. Adaptations versus Exaptations and Span- growth fields, the alveolar and the dentary; drels which make the jawbone and hold the teeth, respectively, have both been getting smaller As opposed to the concepts discussed above, through neotenic human evolution. The fact that which are used to debunk certain findings and to the alveolar has become allometrically smaller oppose research traditions and bodies of theory, compared to the dentary has resulted in the hu- most notably human SB, the following concepts man chin (Gould, 1977b; Lewontin, 1978; Gould are attempts at expanding the number of interest- & Lewontin 1979; Lewontin, 1979; Gould, ing evolutionary structures: spandrels and exap- 1993). Note that in order to identify a spandrel tations. one needs to identify the adaptation as well as The concept of the spandrel was first the developmental constraints or Bauplan. The proposed in Gould and Lewontin’s famous 1979 only way of identifying an adaptation is through paper The spandrels of San Marco and the Pan- the adaptationist program. glossian paradigm: a critique of the adaptationist programme. Spandrels are architectural structures that arise as a necessity of structure, but do

Human Nature Review, Volume 2, 2002, 32 Human Nature Review 2 (2002) 17-61 Table 2 survival and reproduction in an other way than A Taxonomy of Fitness that they were originally designed for, are re- named as exaptations. However most characters Process Character Usage have had such varied “function” historically. Natural selection Adaptation Aptation Function Ridley (1996, p. 348) in commenting on this shapes the char- claims that: acter for a current use- adaptation A character, pre- [M]ost study of adaptation is not con- viously shaped by Exaptation Aptation Effect cerned with the past history of function natural selection changes, but with how natural selection for a particular maintains the adaptation in its modern function (an ad- form. […] Biologists studying current aptation), is co- opted for a new function of organs are not obliged to use- cooptation show that the organ has always served A character the same function. whose origin Exaptation Aptation Effect cannot be as- However, he accepts that “organs undoubtedly cribed to the direct action of can change their function during their history, natural selection and the reason why natural selection is maintain- (a nonaptation) is ing an organ now may not be the reason why it coopted for a cur- initially evolved” (p. 348). This seems to be a rent use- coopta- focus on adaptiveness, and that may not be a tion problem; Wilson’s (1975) methods were good

enough for studies on animals that were under Adapted from Gould & Vrba (1982) and Gould selection pressures similar to those that had (1991). shaped them. Humans are not. Thus one may call

any modern human mental mechanism an exap- The other concept, exaptation, was introduced by tation if the modern human environment is not Gould & Vrba (1982) as a necessary level of adequately consistent with the EEA, but in con- analysis of function and structure, not made pos- sidering the mechanism that evolved due to the sible without an available concept to describe it selection pressure of the EEA one is conceptu- and inspired by the concept of the spandrel (or ally considering an adaptation. Thus in referring nonaptation) (Gould, 1993). Gould & Vrba to the mechanism that is causing the behaviour, (1982) define exaptation as “such characters, whether it is adaptive or not, one is referring to evolved for other usages (or for no function at an adaptation. However if it almost invariantly all), and later ‘coopted’ for their current role” (p. increases current fitness it is either a recently 6). See table 2. They follow Williams (1966) evolved adaptation (unlikely) or it may be called classic division between function, what natural an exaptation (Gould, 1991). selection has designed the adaptation to do, and The interesting point, from the elusive effect, something caused but not selected for (see exclusively adaptationist point of view, is that section III). The non-functional characters are both spandrels and exaptations are offered as spandrels. Also they saw this as a contribution to complementary levels of analysis: adaptations the solution of the problem of preadaptation. The still play a major role (Gould, 1993). This is plu- idea is that the word implies foreordination, ralism. But an exclusively adaptationist point of which is unacceptable. If one changes between view is most likely not the mainstream perspec- different function and effect it becomes mean- tive (Mayr, 1983; Eldredge, 1983); thus all are ingless to claim that the former was a preadapta- pluralists and constraints are accepted by all, as tion to the latter. Gould & Vrba (1982) also ad- well as the power of historical contingency. The dress nonaptations (spandrels), and the article question ends up being one of relevance, and to continues the challenge against the adaptationist the adaptationist natural selection is the only program. The result is that several (functional) evolutionary force able to produce complex adaptations, which are effective in aiding current

Human Nature Review, Volume 2, 2002, 33 Human Nature Review 2 (2002) 17-61 functional design (Dawkins, 1986/1991). the fault of reifying the behaviour (Gould, 1981), Whether this design is actually doing what it and only claiming it is not an adaptation (as EP originally was selected/ designed to do or not, is would agree with) will not help. Gould (1991) beside the point; that would be framing adapta- claims that “Those characteristics we share with tions in the adaptiveness mode of thought (see other closely related species are most likely con- section II). Phyletic new environmental input ventional adaptations” (p. 61). That may be true, will cause novel output from the proximate but he does not explain why, or list these likely mechanism (the adaptation) which may or may adaptations. This opposes EP’s focus on species- not be functional, or adaptive, ultimately speak- typical adaptations; EP defines the species or ing, though an effect will be found (Williams, special Human Nature as the species-specific 1966; Gould & Vrba, 1982; Ridley, 1996). collection of adaptations. On the other hand, Tooby & Cosmides (1990a, 1995) follow Gould (1991) claims that our species-specific this mode of thought when analysing the out- traits are more likely exaptations. Gould (1991) comes of selection: adaptations, concomitants of lists many of the reasons that Pinker & Bloom adaptations and noise. This is an adaptationist (1992), Gazzaniga (1992) and Pinker (1994, account of evolution, and one that most evolu- 1997b) use to show that language shows special, tionists would probably accept as uncontrover- complex design (Williams, 1966; Dawkins, sial. It is not “panselectionist”, it allows for cer- 1986/1991), and that language is an adaptation. tain non-adaptive structures, yet it is neither Pinker & Bloom (1992, p. 486) after discussing “pluralist” enough to fit that label. Maybe this is whether language is better explained as an exap- due to adaptationism not being panselectionism, tation or an adaptation based on a Chomskian because the description of the panselectionist is a interpretation of data, but adding a computa- non-existent caricature. The great difference may tional theory/ ultimate level explanation (see sec- be more a question of focus and interest of study, tion III) conclude: and a result of Weismann’s Mendelism being such a forging influence on the Modern Syn- [H]uman language, like other specialized thetic theory. This only allows room for “plural- biological systems, evolved by natural ists” to expand evolutionary theory. It does not selection. Our conclusion is based on two falsify the existing theory by default. facts that we would think would be en- So far the discussion has focused on tirely uncontroversial: Language shows adaptationism as it pertains to the foundations of signs of complex design for the commu- EP, but debated mostly within biology. Lately nication of propositional structures, and the discussion has entered psychology proper. the only explanation for the origin of or- Gould (1991), Exaptation: A Crucial Tool for an gans with complex design is the process Evolutionary Psychology, is an attempt at advo- of natural selection. Although distin- cating his own version of evolutionary psychol- guished scientists from a wide variety of ogy; he does not discuss EP. He does mention fields and ideologies have tried to cast Pinker’s mental mechanisms, in passing, but doubt on an orthodox Darwinian account keeps to the Fodor (1983,1985) line that percep- of the evolution of a biological speciali- tion is modular, but consciousness is not (Gould, zation for grammar, upon examination 1991), and chooses to use Chomsky’s version of none of the arguments is compelling. language, as an example. I find that the lack of discussion of the existing theoretical body of EP Gould’s (1991) conclusion is that language is an puts Gould at a disadvantage. His discussion is exaptation. Exaptations come in two forms: co- still being framed against SBs (Gould, 1991), option of spandrels or of adaptations, the latter much on their terms as when Gould offers the being close to the old concept of preadaptations, spandrels of language or modern warfare without thus have an inherent function that has lately explaining what kind of mechanism may be be- (evolutionary speaking) lost this function and hind it. By defining the evolved product of acquired an effect. The spandrel would be non- modern warfare as an unspecified, presupposed, functional from the start, and would be the more structure, Gould (1991) is close to committing structuralist alternative. By suggesting that the

Human Nature Review, Volume 2, 2002, 34 Human Nature Review 2 (2002) 17-61 brain grew for an unknown adaptive reason, and tions must greatly exceed adaptations in number even by offering what could hardly be anything and importance” (p. 55). One can be tempted to but a Just So Story (sic!); though one of struc- conclude that Gould believes that there never tural effect not cognitive function, Gould (1991, was a reason why the mind would evolve, only p. 62-63) is defining the resulting co-optable fea- the physiologically framed version of the brain, tures of this structural change as spandrels. Lan- also that there never was a strong selection for guage is considered a likely spandrel of brain adaptations that were better at solving survival growth, and a likely reason for brain growth is and reproduction problems cognitively. This that the brain is a “radiator”, an “efficient cool- sounds very unlikely, given the intra-species ing device” needed to protect against the “in- arms races (Dawkins & Krebs, 1979; Dawkins, tense solar radiation of savannah habitats” fa- 1982) that would cause an exaptation of these voured by our ancestors (Gould, 1991, p. 62). spandrels and thereafter adapt them through se- Why should this be a likely or even good inter- lection, once they were present, for surely it pretation of data? Gould concludes that this is a must be possible for natural selection to adapt less threatening construct “for those feeling the exaptations. breath of biological imperialism” (Gould, 1991, Recently Buss, Haselton, Shackleford, p. 63). It is also “opposed to the conventional Bleske & Wakefield (1998) have published a Darwinian account”; it is “quirky and unpredict- response to Gould’s (1991) alternative. They re- able”, “contingent”, and “discontinuous”, all in act to the definition of the exaptation as enhanc- all almost impossible to use for scientific inves- ing current fitness, as this does not explain why tigation. Though the pluralist alternative was it arose (Tooby & Cosmides, 1990b) and adap- originally presented as being able to “put organ- tiveness is not an interesting focus for explana- isms, with all their recalcitrant, yet intelligible, tion, unless the environment of current adapta- complexity, back into evolutionary theory” tion is similar to the EEA (see sections II & III). (Gould & Lewontin, 1979, p. 597)- note the The functional analysis of evolutionary explana- word “intelligible”, pluralism does “not offer a tion focuses on why a trait exists, not the current council of despair […] for non-adaptive does not effect it has in interacting with the environment mean non-intelligible” (p. 597). Thus exaptation (Buss et al., 1998). Buss et al. (1998) discuss ends up being a tool for not accepting EP; it is an several of the terminological and conceptual argument for the position that any causal or confusions due to theoretical inconsistency in functional analysis is impossible, unless one Gould & Vrba (1982) and Gould (1991). Their wants to study physiology. This may be consid- conclusion is that there is utility in the concept of ered a modern version of dualism (although that exaptation. In focusing solely on Gould & attack has been aimed at “adaptationism” too, Vrba’s fitness enhancing definition, Buss et al. see Oyama [1991]). (1998) catch Gould & Vrba’s concept of exapta- Gould (1991, p. 48-49) starts off with tion in the functional, evolutionary analysis of two opposing positions for accepting an evolu- EP; which in itself proves to be a mature and ef- tionary psychology: the brain might be “altered fective analytical tool - the point I find most in- and enlarged under natural selection”, but “adap- teresting with the discussion. They also show tationism” is the base of “dubious social behav- that Gould’s (1991) proposed exaptations of iors” like “colonial expansionism”, “industrial writing and reading are too new historically be exploitation” and “modern sexism”. Thus, co-opted by natural selection. Thus these activi- though Gould wants an evolutionary psychology, ties must be a product of or co-opted by existing he cannot advocate adaptationism. The remain- human mechanisms. I would like to add that ing alternative is therefore to “seek a more ade- since Buss et al. (1998) specifically focused on quate evolutionary version” (p. 49). This version the fitness enhancing criterion of exaptation, it is is what Gould (1991) is attempting to formulate. surprising how effortlessly they were able to dis- In this version adaptations are not interesting qualify several of Gould’s (1991) examples of when considering Human Nature, or current hu- exaptations by invoking that criterion. The im- man behaviours, because spandrels “determine portant point is that Gould (1991) lists several the design of the ‘main’ structure” and “exapta- proposed exaptations, without these being in any

Human Nature Review, Volume 2, 2002, 35 Human Nature Review 2 (2002) 17-61 way analysed as fulfilling the criteria of exapta- adaptationist concept. I find Buss et al.’s (1998) tion (Buss et al., 1998). Buss et al. (1998, p. analysis important, but too willing to co-opt 546), after accepting the value of the concepts of exaptation as an adaptationist concept; it speci- exaptation and spandrels, further highlight the fies much the same problem I find with Gould & fact that in order to call a trait either an exapta- Vrba’s exaptations, but does not make enough of tion or a spandrel one has to identify an adapta- the lack of conceptual consistency. My initial tion: problem with exaptations is this: Are they or are they not potentially designs for later selection? I Although all three concepts require cannot see how these traits can escape this. Their documentation of special design for a effect is, to at least some extent, due to genetic hypothesized function, co-opted exapta- makeup, as much as any other biological trait. tions and spandrels carry the additional Thus, as they currently are enhancing fitness, evidentiary burdens of documenting both they are causing a differential replication of the later co-opted functionality and a distinct genes for the trait, and thus effectively an exap- original adaptational functionality. To tation by definition is only a passing concept. our knowledge, none of the items on Gould (1991) claims that an exaptation may be Gould’s (1991) list of proposed spandrels redesigned by secondary modification. He calls and exaptations- language, religion, prin- this “superimposed, true adaptation” (p. 47). All ciples of commerce, warfare, reading, the same he claims this “tinkering does not alter writing, and fine arts- have met these the primary status of such a structure as coopted standards of evidence. Moreover, even if rather than adapted” (p. 47). So due to some trait they did meet such standards, this would changing from having biological, ultimate func- in no way diminish the need to place tion to having current effect it is no longer an such items within an overall evolutionary adaptation but an exaptation, even though it has framework in order to adequately under- been redesigned by natural selection (sic!) in or- stand and explain them- a point agreed in der to be “effective” and “it enhances fit- by all sides of these debates. ness”(sic!). One might conclude that renaming the structure and removing the function is the I find that Buss et al. (1998) take advantage of main objective; there are no important adapta- the understanding of function, which is ulti- tions, and thus adaptationism is bankrupt. Con- mately connected to differential gene replication sider Gould’s (1991) own example: “the elabo- or inclusive fitness, and apply it to the definition rate plumages and behavioral displays of male of co-opted spandrels (or nonaptations) and ad- birds of paradise are true adaptations for mating aptations as exaptations, which do not have func- success” (p. 47). Feathers in birds were by Gould tion, they only have effect (Gould & Vrba, 1982; & Vrba (1982) already defined as exaptations for Gould, 1991; Williams, 1966; Ridley, 1996), in flight, as Gould points out in the paragraph pre- such a manner as to allow for an adaptationist ceding the quote; previously (or originally) the analysis. This results in a correct semantic analy- function of feathers was thought to be thermo- sis, but I consider that it misses the intention of regulation (Gould & Vrba, 1982; Gould, 1991). Gould (1991). See table 2. Buss et al. (1998, p. Gould has allowed for “tinkering”, selection 539) are aware of the different definitions in (sic!), to make thermoregulatory adaptations ef- Gould & Vrba (1982) and Gould (1991), and I fective exaptations for aerial locomotion, but not agree with Buss et al. (1998) that the conceptual adaptations for aerial locomotion; although the problem lies with Gould & Vrba (1982) and elaboration of the same thermoregulation in or- Gould (1991). But in their attempts to solve the der to mate successfully is not considered a confusion that arises Buss et al. (1998) focus exchange in function, or an exaptation, but is given clusively on the quote that exaptations are “fea- status as an adaptation. I consider these inconsis- tures that now enhance fitness, but were not built tencies in Gould’s conceptualisation of the exap- by natural selection for their current role” (Gould tation to be important enough to postpone use of & Vrba (1982, p. 4; Gould, 1991, p. 46). This the concept until it is possible to differentiate causes exaptation to be rendered solely as an between effect and function (Williams, 1966;

Human Nature Review, Volume 2, 2002, 36 Human Nature Review 2 (2002) 17-61 Ridley, 1996), and to specify what kind of selec- Criticism of certain concepts, and the ad- tion or how much selection is needed in order to dition of others, is obviously necessary when be able to accept the character as an adaptation developing a body of theory, and as the major again. Of course, if Buss et al.’s (1998) reformu- critic of modern evolutionary theory Gould has lated conceptualisation is incorporated into adap- performed an admirable service. This being said; tationist thinking, then this might have certain most of his major points are either assimilated or value. rejected in major articles within evolutionary My conclusion is that by entering the science, and as such a new theory does not seem psychological domain as an evolutionary theo- warranted, though additional work on macroevo- rist, as he has done previously; with splendour lutionary phenomena and developmental theory (Gould, 1981), Gould is also inviting psycho- is needed (Williams, 1985; Maynard Smith, logical analysis of evolutionary theory. From 1986). within psychology, Buss et al’s (1998) response, The adaptationist program seems empiri- proves the academic maturity of EP’s adapta- cally and methodologically secure, as the main- tionist theorising. The theory of evolution is be- stream evolutionary scientific approach. As such, coming ever more interdisciplinary within the any evolutionary psychology would be well ad- life sciences. vised to primarily attempt to develop within this framework, before attempting to expand it. IV.V. Summary and Conclusions V. Demarcation and Inclusion: EP and Three Both sides have a tendency to refer to Darwin’s Important, Wrongfully Perceived Paradoxes Origin (1859/1996) or later works to argue that their position is orthodoxy (Gould, 1993), al- This section attempts to address three perceived though Gould, critical of this on the one hand, paradoxes of EP. First, as a theory founded on often seems in his essays and articles to do this the Modern Synthetic theory, it is ultimately most explicitly, offering the “correct” interpreta- based on genetics. Unlike the adaptiveness- tion of Darwin’s work (Gould & Lewontin, oriented SB, adaptationist EP does not share the 1979, p. 589; Gould, 1993, p. 312; Gould, 1997a, focus of behavioural genetics. Adaptations have 1997b). The Modern Synthesis depends on Dar- close to zero heritability, whereas behavioural win being wrong or agnostic about processes of genetics study behaviour that has high heritabil- heritability and genetics. Gould invokes Dar- ity. Second, a commonly accepted influence of win’s own call for pluralism, but as critics of Darwinism on psychology is the use of compara- Darwin’s brand of pluralism point out Darwin tive studies, due to the explanation of accepted included almost any current theory in addition to common features of all animals. EP is more re- his own in order to withstand the criticism of his strictive than mainstream psychology in this re- ideas. Gould & Lewontin (1979) even make a spect, focusing almost exclusively on species- point that they do not “regard all of Darwin’s specific or species-typical adaptations, which as subsidiary mechanisms as significant or even a system define the species. Third, there is a per- valid”, though they advocate his “attitude of plu- ceived paradox between focus on adaptations ralism in attempting to explain Nature’s com- (the innate behaviour modifying mechanisms) plexity” (p. 590). One may claim that the attitude and learning. This is not a problem within EP. of pluralism was a forced move in order to pro- Environmental factors are considered vital to the tect the theory of selection, due to the lack of a development of any adaptation and constitute the theoretically acceptable theory of heredity, as input for mental mechanisms to process and re- Darwin’s own theory of heredity would not al- turn as behavioural output. An exposition of low for selection to work (Dennett, 1995; Ridley, these three topics is necessary in order to under- 1996). A move that no longer was necessary stand fully the implications of EP’s theoretical with the re-discovery of Mendel’s work by Au- foundations for psychology. gust Weissman in the early 1890’s, thereby allowing Weismann and Huxley’s “panselectionism” rather than “pluralism” (see Gould, 1993).

Human Nature Review, Volume 2, 2002, 37 Human Nature Review 2 (2002) 17-61 V.I. EP versus Behavioural Genetics An adaptiveness-oriented approach to existing genetic variance, which does not “underes- Behavioural genetics (BG) addresses “the ge- timate the power of natural selection”, will ex- netic and environmental sources of differences plain this variance as a result of current condi- among individuals” (Plomin, 1989, p. 105; see tions - or vice versa: current conditions cause the also Bouchard, Lykken, McGue, Segal & existing genetic variance. This leads to the idea Tellegen, 1990, p. 228), not human universals or that an evolutionary approach to Human Nature differences between gender-groups or other is a biological determinist, political statement groups. EP addresses Human Nature as ex- about current socioeconomic differences, advo- pressed through mental adaptations, where ge- cating the naturalness and status quo of existing netic differences among individuals will be con- inequality (Rose et al, 1984). sidered “perturbations in these mechanisms” BG is not committed to an adaptiveness- (Tooby & Cosmides, 1990a, p. 18), due to the oriented approach, but has been inspired by and likelihood of random genetic change increasing is theoretically compatible with SB where exist- entropy. Thus EP does not address differences ing genetic variance is considered adaptive. The between human groups, with one exception: major theoretical difference between BG and SB gender-specific adaptations (Tooby & Cosmides, is the unequal focus on explaining the variance 1990a; Gaulin, 1995; Buss, 1995a). as a result of selection forces or not, as well as Bailey (1998), considering the possibility the focus on differences between groups. Within of reconciling the differences between EP and BG one does not object to the idea of genetic BG, focuses more on the possibility of signifi- variance that modifies adaptations being adap- cant genetic variance between group differences tive (Bailey, 1998). This may easily be confused than either Plomin or Cosmides & Tooby. The with adaptiveness-oriented approaches, but is not lack of interest in differences between groups necessarily similar, the difference being that the due to genetic-variance in Plomin’s BG or Cos- adaptive variance need not be selected for the mides & Tooby’s EP is not the exclusive theo- here-and-now environment - rather selection has retical stance within psychology, there is a tradi- caused the variance in evolutionary time. tion for this focus within psychometrics dating EP’s approach to genetic variance is from Francis Galton via Arthur Jensen to quite different. Tooby (1982) addressed the vari- Herrnstein & Murray’s (1994) The Bell Curve. ance from an immunological point of view as The focus in this section will be the difference well as attempting to explain the evolutionary between EP and BG in accepting traits with sig- paradox of sexual reproduction. Sexual repro- nificant heritability as significant targets for sci- duction without genetic variance is pointless, but entific enquiry. any gene has only a 50% chance of being passed Adaptations are created through the se- on to next generation (at each successful mat- lection of the better combinations for survival ing), and the individual’s genotype is lost, as and reproduction given the existing selection well as a functional design that was a product of forces and genetic variance. Genetic variance is that specific genotype (in that specific environ- depleted during selection, as the fitness enhanc- ment). Tooby & Cosmides (1990a) claim that ing genes out-compete their less fitness enhanc- “sex is clearly an adaptation” (p. 31), so there ing alleles. There do exist cases where there is a must also be benefits, not only cost. Tooby’s frequency dependent selection for different al- (1982) answer is that sexual reproduction and leles. These are called polymorphs, and may be genetic variance (which does not disrupt design understood by applying the ESS-model, where monomorphism) both are evolved defences the frequency of the different strategies as a sys- against pathogens. Pathogens evolve at a higher tem is evolutionary stable and thus adaptive rate than humans, or other large, longevous ani- (Dawkins 1980, Maynard Smith, 1979). Bailey mals; they may therefore evolve to crack the (1998) looks at several other mechanisms that immunological code of the larger organism, may maintain genetic variation, like antagonistic unless this code is constantly different due to pleiotropy, but admits that most of these are con- genetic variance and sexual reproduction. The troversial among adaptationists. same arms race (Dawkins & Krebs, 1979) may

Human Nature Review, Volume 2, 2002, 38 Human Nature Review 2 (2002) 17-61 be observed between bacteria and human- variation, adaptations are therefore structures designed antibiotics; the antibiotic has a certain that have a genetic base, but no or low heritabil- biochemical effect, and unless it is changed the ity, as defined within genetics. Humans do not bacteria will evolve resistance. Thus “noise” or vary qualitatively in their cognitive architecture. superficial variance is adaptive, especially in Mental mechanisms, as adaptations, are mono- longevous species. Tooby & Cosmides (1990a) morphic, although EP accepts quantitative varia- offer this as the explanation to “the paradox of tion (Tooby & Cosmides, 1990a). design monomorphism in a world of genetic As mentioned above there is one be- polymorphism” (p. 30). Variance in the geno- tween-group effect that receives attention within type of adaptations is thus superficial; it does not EP: gender differences. Gaulin (1995) argues affect the adaptation in an ultimate functional that evolutionary theory predicts sex differences manner, although it may be measured by genetic in the brain; such differences are caused by sex- research. Also, if Tooby (1982) is correct that ual selection (Darwin, 1871/1981) a result of dif- parasitism is a major selection pressure, then one ferent reproduction-problems between the gen- will have a frequency dependent selection caus- ders. Apart from the Y-chromosome, all genes ing the more common allele to become maladap- have been equally present in males and females tive, and the more superficial variation (accumu- through phyletic history. The key to differentia- lation of genes that differ biochemically, but tion is therefore the affects of the Y- give rise to the same design) will accumulate at chromosome, which carries the gene called testes different loci. One may note that the interaction determining factor (TDF). The testes produce of these “reserve” genes may be potential vari- androgens, which literally turn the foetus into a ance for later selection, even though they when male, by affecting the autosomes “environmen- they became a part of the gene pool “coded” for tally”. Gaulin (1995, p. 1214) concludes: similar designs. Tooby & Cosmides (1990a) refer to Rose et al. (1984), who note that the major In this way, genes that only one sex car- variance is between individuals and not between ries (genes on the Y) produce a signal of geographical populations, in order to substantiate sexual identity for the rest of the geno- their claims (an unusual and refreshing fraterni- type. Against this reliable background sation with the anti-adaptationists, worth noting). signal, selection has apparently con- Tooby & Cosmides (1990a, p. 35) sum up the structed a wide array of modulatory potentially surprising finding of genetic variance mechanisms that restrict the expression among humans thus: of sexually competitive traits to the sex where they will produce the net benefit. Human groups do not differ substantially in the types of genes found, but instead EP’s stance is thus more restrictive than the only in the relative proportions of those adaptiveness-oriented approach, as environ- alleles. Eighty-five percent of human ge- mental differences will be expected to be influ- netic variation is within-group variation, ential and only adaptations predicted by survival 8 % is between tribes or nations within a or reproduction-problems in the EEA of these “race,” and only 7 % is between “races” traits are addressed. […] This result […] is consistent with the BG has documented the influence of ge- pathogenic theory: People catch diseases netic and environmental variance on a large ar- from their neighbors, so it is important to ray of human behaviours (Plomin, 1989; Plomin, be genetically different from them… Owen & McGuffin, 1994; Plomin, DeFries, McClearn & Rutter, 1997; Bouchard et. al. 1990; Note that the idea of human “races” becomes Bouchard, 1994; Bouchard, Lykken, Tellegen & meaningless, a point taken by EP: “There is no McGue, 1996; Bailey, 1998). This approach to structured genetic substrate separating human the study of humans has been controversial for groups discretely into different kinds” (Tooby & years (see Rose et al., 1984), but Bailey (1998, p. Cosmides, 1990a, p. 35). Tooby & Cosmides 219) concludes: today it is not interesting “re- (1990a) conclude that as selection eliminates

Human Nature Review, Volume 2, 2002, 39 Human Nature Review 2 (2002) 17-61 jecting the null hypothesis that heritability is variance is not a point; the traits mentioned are equal to zero.” inherited but need not have greater than zero The fact that EP, as a theory of inherited heritability due to selection (in the case of do- (genetically based) Human Nature, does not ad- mesticated animals this would be artificial selec- dress those traits that have high heritability and tion, on top of previous natural selection). Thus which are focused on by BG may be potentially quoting Darwin does not address the question surprising. The near zero heritability demand is whether the BG approach to personality is inter- due to the theoretical resistance to viewing ge- esting or even if genes are the mechanism in- netic variation as adaptive, as natural selection volved. will reduce variation in designing the adaptation Bouchard et al. (1990, p. 228) identify through the effect of differential rates of repro- the interface of BG and SB as “the question of duction. The lack of overlap between the scien- the origin and function, if any, of the within- tific focus of BG and EP is due to their initial species variability” discussed within BG. Bou- disagreement on whether genetic variation is chard et al. (1990) do not differentiate between adaptive or not, and due to one describing indi- SB and EP. The question continues to be vidual differences in the present and the other whether genotypic variance is noise or adapta- predicting universal Human Nature due to evolution, and is the phenotypic variance noise or ad- tionary principles. aptation. Bouchard et al. (1996) attempt to pro- Bailey (1998) questions whether this in- vide an answer. They start by questioning the EP dependence or opposition of focus may be scien- point of view of natural selection having de- tifically resolved, focusing on the reluctance signed mental adaptations in the same manner as within EP to address the substantial invariably our physiology, which “is monomorphic within a found variation, which BG has shown to be, to a functional design” (Tooby & Cosmides, 1990a, large extent, genetic in origin. Bailey (1998) ob- p. 29). Bouchard et al (1996) claim that identify- serves that EP explains variance in traits due to ing physiological adaptations that are phyloge- environmental variance, but advocates consid- netically ancient, characters of the mammalian eration of the question of how particular behav- line or earlier, and comparing them with the ioural variance is adaptive. This would be the more recent human mental adaptations, allows first step in distinguishing “empirically between one to question whether selection has had time to adaptive genetic variation and a universal Hu- fix the mental adaptations genetically, or if man Nature’s contingent responses to different “most of them are in a transitional phase” (p. environments” (Bailey, 1998, p. 226). This ques- 32). The logic of Bouchard et al. (1996) slips a tion may appear to focus on current behaviour little when they thereafter compare the genetic being adaptive, rather than the pattern of envi- variance of mental adaptations with physiologi- ronmentally contingent behavioural responses cal adaptations in order to question whether the which may be used to infer the existence of a variance is superficial or not; the monomorphism mental mechanism - the adaptation. As such it of the phyletic older traits was an accepted would not bridge the theoretical cleft between benchmark, a likely fixed trait, used to question EP and BG, but rather be an expression of the the fixation of mental adaptations. Second, the more familiar theoretical and empirical connec- “ongoing selection” hypothesis and the “adaptive tion between psychometric-traditions, adaptive- effect of genetic variance as a means for adapta- ness-oriented human SB and BG. tion” arguments are offered. The former as an Bouchard (1994) quotes Charles Darwin opposition to the idea of one, monomorphic, as evidence of the age of the idea of genetic in- Human Nature, and Tooby’s (1982) theory of the fluence on behaviour, including personality. adaptive effect of sexual reproduction as a de- Darwin (1871/1981) addresses transmission of fence against parasites in longevous species. In traits that define the species or breeds of domes- such a framework, some genes are better than ticated animals. Darwin, as he most likely had others, and populations will differ in respect to not read Mendel’s work (he owned a copy, but mental abilities and functioning due to genetic left the pages uncut), is not really talking about differences. The latter argument is teleological. “genes” and in the quote offered by Bouchard The variance may not exist in case of specific

Human Nature Review, Volume 2, 2002, 40 Human Nature Review 2 (2002) 17-61 change, but a greater mutation rate may be se- dictable or universal, and need not be explained lected for, as long as it does not become mal- as adaptive. adaptive (the design must not be subject to too much entropy, it must replicate with a high V.II. EP versus Comparative Psychology enough fidelity in order to ensure a relatively stable transmission). EP’s perspective is that any The common origin of all life, explained by genetic variance, which does not affect adapta- Darwin’s Origin (1859/1996), is the major theo- tions, is superficial variation, and attempts there- retical foundation for comparative studies. fore to discover phenotypic design patterns, Among the shared traits of all living creatures which due to their nature as adaptations are ex- (Skinner, 1983), psychology has focused on the pected to be monomorphic. Bouchard et al. general principles of learning. The focus on spe- (1996) conclude that the fundamental thrust of cies specific responses grew out of the behav- EP is correct (that is EP’s theories of modularity iouristic research on what was originally pre- and origin of mental traits), but they also quote sumed to be general and plastic, but which their earlier conclusion regarding BG’s relevance proved to be governed by each individual species to EP: “If genetic variation was evolutionary de- predispositions. The implications for learning bris at the end of the Pleistocene, it is now a sali- will be elaborated further below. ent and essential feature of the human condi- So far the terms “species-specific” and tion.” (Bouchard et al 1990, p. 228). “species-typical” have not been discussed. “Spe- The differences between EP and BG are cies-typical” would be an adaptation that defines mainly issues of focus and method, to cite a species, a species’ universal trait. “Species- Plomin et al. (1997): specific” demands more attention, as many adaptations are shared by many species. Within evo- [I]nvestigating the causes of average dif- lutionary theory, the concepts of “homology” ferences between species, which is the and “analogy” are used to differ between per- focus of [EP], is a different level of ceived similar adaptations. A homology is a analysis that asks questions and gets an- “[c]haracter shared by a set of species and pre- swers different from those asked and re- sent in their common ancestor” (Ridley, 1996, p. ceived in investigation of the causes of 665), there is therefore reason to believe that the individual differences within species, (in the case of psychology) neurological struc- which is the focus of [BG]. ture and genetics are relatively similar. An analogy is a “[c]haracter shared by a set of species If EP is to be evolutionary and adaptationist then but not present in their common ancestor” EP’s must focus on evolutionary time, the selec- (Ridley, 1996, p. 665), and there is no reason to tion pressures of a statistical composite like the believe that the neurological structure or genetics EEA, and predict adaptations that are universal need be similar. Thus a species’ adaptation may for all humans, or specific to gender (or any be genetically equivalent, or approximately group that has had statistically stable, different equivalent due to certain changes, and although survival or reproduction problems over evolu- this prevents a single adaptation truly being spe- tionary time, which is why gender-specific adap- cies-specific an sich, the coadapted system of tations may exist). Thus actual here-and-now adaptations may be. Also, species facing similar differences in grade will not be evolutionary survival or reproduction problems may evolve predictable. However, genetic variance will be similar adaptations to solve the problems - as predicted due to mutations and the nature of such the evolutionary adaptationist comparative meiosis and sexual reproduction. What also may model is a theoretically rigorous approach to in- be predicted is the fact that variance in itself may ter-specific studies. be adaptive, and has been so for as long as sex- One example of this approach is Gaulin ual reproduction has existed. A genetic variance (1995) who describes how one may use the ad- discovered in BG to be large enough to be sig- aptations discovered in one species to predict nificant will not necessarily be evolutionary preadaptations in another species that faces similar survival or reproduction problems. Note that the

Human Nature Review, Volume 2, 2002, 41 Human Nature Review 2 (2002) 17-61 reason why the comparative approach is theo- expense of what they deemed an exclusively en- retically valid is not the idea that the adaptations vironmentalist discipline: behaviourism. This are homologous but that they solve similar sur- caused a certain debate, as Todd (1987a, 1987b) vival or reproduction-problems. disagreed with the validity of Gould & Marler’s Preuss (1995) argues how the idea of (1987a, 1987b) historical and theoretical descrip- similarity and continuity within neuroscience in tion of Behaviourism. Gould & Marler’s contri- regard to representative neural architecture is butions to this debate were fuelled to a certain opposed to modern evolutionary theory, where degree by the negative responses that Garcia “[t]he changes organisms undergo in evolution (1981) describes his work, on the constraints of represent departures or deviations from an ances- learning, received from journal-editors. tral condition, rather than different expressions The priority of innate factors for learning of a common type” (p. 1230). Preuss (1995) does not mean that learning is not important concludes that a “review of the literature sug- when explaining behaviour. It does mean that an gests that mammalian brains display a number of organism cannot learn without biology. Learning remarkable variations, at several levels of or- itself is something a living organism is capable ganization” (p. 1231). The existence of neural of doing due to being a living organism (see diversity implies that non-human species may Skinner, 1983). As Öhman, Fredrikson, Hugdahl have evolved mental mechanisms that did not & Rimmö (1976) point out, the evidence that evolve or have been lost in humans (Preuss, biological constraints exist has come from within 1995), just as we have evolved human-specific learning psychology (e.g. Garcia & Koeller, adaptations. 1966; Bolles, 1970; Seligman, 1971, Seligman & Tooby & DeVore (1987) offered the Hager, 1972; Öhman et al., 1976). The organism same line of argumentation in order to explain is predisposed to learn specific responses, and why modelling human evolution by course of may be unable to learn others, due to no existing representative modelling would be invalid per se neural potential within the organism to perform unless based upon a rigorous conceptual model certain tasks. Potential is as much a question of (See section III). This extends a special status to hardwiring as plasticity and size (for contrast see humans, but not more special than other animals; Gould, 1991, on brain size and function). There we are special in encompassing our particular are biological constraints, as well as predisposi- integrated system of adaptations and we remain tions, to learning. products of evolution. Williams (1985) argues for the stringent, Due to this, EP ends up being interested antimentalistic behaviouristic language within in typical species-adaptations, which as a co- animal behavioural ecology studies, although adapted system will be species-specific. This Dawkins (1981, 1983) and Dennett (1983) advo- prevents EP from committing the more hazard- cate the opposite stance. Behaviourism has since ous inter-species generalisations for which Wil- merged to a great extent with cognitive psychol- son (1975) and other SBs were notorious. At the ogy both within the experimental domain, e.g. same time a description of the different species’ Rescorla’s (1988) focus on stimulus as informa- EEA may predict analogous adaptations, and as tion, and the clinical domain, e.g. Kanfer & Phil- such provide information about possible adapta- ips’s (1970; see also Mash & Terdal, 1988) tions one may expect to find in a specific species SORCK model. This allows for the language of based upon knowledge of the adaptations of an- biology to follow up the cognitive shift without other species. having to worry about the scientific value of the new cognitive terminology. The merger of all V.III Learning and EP three traditions influences EP - evolutionary ethology, contextual learning psychology and Gould1 & Marler (1987a) heralded the idea of modular cognitive psychology. the priority of innate factors for learning, in their Learning, predispositions and domain- article Learning by Instinct. They did so at the specificity may explain the ontogenetic development of adaptations, the calibration of mental- mechanisms, and the re-setting of the same 1 NB! James L. Gould, not Stephen Jay Gould.

Human Nature Review, Volume 2, 2002, 42 Human Nature Review 2 (2002) 17-61 mechanisms in examples like phobias and anxi- based upon knowledge from the psychology of ety (see section VI.II.). learning, both ethological studies and main- Todd (1987a, 1987b) wants to preserve stream behaviouristic studies, as well as the de- behaviourism, and claims behaviourism already veloping theoretical body within both evolution- is informed of the synthesis Gould & Marler ary biology and psychology proper. (1987a) are heralding, thus adding Garcia to the EP is interested in the human species’ behaviouristic tradition. Gould and Marler specific coadapted system of adaptations. To the (1987a, 1987b) are opposing what they perceive extent that particular survival and reproduction as an overly environmentalist tradition within problems have differed for males and females, learning, and want to shift focus to the innate gender-specific adaptations are expected to have biological constraints and predispositions for evolved; these will have to be tied to Y- learning. The survival of behaviourism (Todd, chromosome effects. Human adaptations are 1987b) is hardly a point in it self, as the ideas considered universal to the human species. Thus and theory the research programme has borne are there is little or no focus within EP on genetic durable truths of the science of psychology. Hy- variance between individuals, as long as it does pothesising equipotentiality allows research to not disrupt adaptations. Comparative studies and attempt to falsify this idea, it could not falsify a inter-specific generalisations are not the fa- research program attempting to “discover the voured. This lack of overlap of interest between rules of learning” – however, uniting research EP and BG, and comparative, studies may ini- programs and creating synthesis might naturally tially seem paradoxical, and the aim of this sec- lead to a lessened necessity for “sectarian” lation has been to provide the theoretical argument bels; “learning psychology” ought to be ade- for the differing interest. quate. Since Seligman & Hager’s (1972) Bio- Just as one would expect EP to be com- logical Boundaries Of Learning learning psy- patible with BG and comparative studies, one chology has been biologically informed, just as might expect EP to be in opposition to general ethological perspectives to behaviour are in- learning theory. The fact that EP is inspired by formed by learning psychology (Houck & discoveries within learning and is focused on Drickamer, 1996). environmental input for the development of ad- The step EP is calling for is that the find- aptations might be perceived as paradoxical by ings of learning psychology also apply to cogni- some. There does not appear to be any reason for tive psychology; the modularity, species- a conflict between EP and learning. Rather the specificity, and biological preparedness of mind, findings of biological preparedness and modular- mirror the way certain species solve their sur- ity found in learning psychology may inform the vival and reproduction problems, also when the study of mind. adaptation needs contextual input, learning and Much of the criticism toward earlier development. EP advocates the abandonment of Darwinian oriented approaches to Human Nature the false dichotomies of “nativist” vs. “environ- and behaviour is dissolved within the mature mental”, “biological” vs. “social”, “genetic” vs. theoretical framework of adaptationist EP. “environmental”. As Tooby & Cosmides (1992, Whether EP is a new school of thought, which p. 87) claim: “All ‘environmentalist’ theories would cause a shift of paradigm within the sci- necessarily depend upon and invoke ‘nativist’ ence of psychology, or a comprehensive reor- theories, rendering environmentalism and nativ- ganisation of existing biological and psychologi- ism interdependent doctrines, rather than op- cal empirical findings and theory remains to be posed ones.” seen. This is the theme of the next section: a look at EP’s effect on academic psychology. V.IV. Summary and Conclusions VI. The Influence of EP on Academic Psychol- While most of the false expectations to EP’s ogy: A Scientist-Practitioner Perspective stance to these three topics are due to a popular knowledge of adaptiveness-oriented SB, the rea- The following section will briefly consider EP’s son why EP does not take the expected stance is influence on mainstream academic psychology,

Human Nature Review, Volume 2, 2002, 43 Human Nature Review 2 (2002) 17-61 before illustrating the theoretically unifying po- have prevented any inspiration to seek the an- tential of EP on academic psychology, as well as swer within adaptationism. This remains much practice, through a more detailed look at clinical the same backdrop for critiques such as Le- psychology, or Evolutionary Psychopathology wontin (1990), Davies (1996a, 1996b) and (EPP). Richardson (1996). EP is continuously inspiring authors within cognitive psychology, as illus- VI.I. EP’s Influence on Mainstream Academic trated by Wells (1998) and Kenrick, Sadalla & Psychology. Keefe (1998).

Social Psychology. The major selection force Cognitive Psychology. Cosmides & Tooby’s driving human evolution has very likely been (1987, 1992, 1994a, 1994b, 1995, 1997; Tooby other humans. Therefore social cognition plays & Cosmides, 1995; Cosmides, 1989; Tooby, an important role within EP, e.g. Cosmides’ 1988) EP is a cognitive as well as biological (1989; Cosmides & Tooby, 1992; 1997) research psychological theory, and as such it has inspired on social exchange and cheater-detection- cognitive neuroscientists. Davies’ (1996a) claim mechanisms, using the Wason selection task that EP “is a species of cognitive psychology” (Wason, 1966, 1983). This is why Buss & Ken- (p. 445) ought not to surprise anyone. Gazzaniga rick (1998, p.982), may claim that social psy- (1995a, 1995b) views EP as the new perspective, chology “is not merely an additional domain of guiding his own thinking and research, and he [EP]; it is the central domain”, in their recent has actively promoted EP in his work (Gazza- article in the Handbook of Social Psychology niga, 1992, 1995a, 1995b). Thus EP has become (Gilbert, Fiske & Lindzey, 1998). The cognitive a serious contender as the guiding theoretical influence on social psychology facilitates the framework within modern, mainstream Cogni- adoption of EP within social psychology. Also tive Neuroscience. Pinker (1997a) provides in the new focus on family studies (Buss & Ken- his book How The Mind Works an extensive rick, 1998) and placing social relationships at the presentation of evolutionary, adaptationist cogni- core of social psychology (Buss, 1997; Buss & tive psychology. Both Gazzaniga and Pinker are Kenrick, 1998), is informed by an analysis of the inspired by the work of Cosmides & Tooby, and survival and reproductive problems males and accept as the main points the modularity of females, respectively or commonly, faced during mind, the functional approach to investigation of the adaptation-specific EEA. Recently Simpson mental processes and the adaptationist approach & Kenrick (1997) edited a collection of articles to the evolution of functional mental organs. called Evolutionary Social Psychology, covering Chomsky argued for the modularity of themes from descriptions of evolutionary theory mind with his theory of mental organs, as did and EP’s relevance to social psychology (Ken- Fodor (1983, 1985), but none of them accept the rick & Simpson, 1997; Buss, 1997) to studies of modularity of all of mind (Davies, 1996a). Marr social psychological phenomena such as social (1982) advocated the computational or func- perception (e.g. Springer & Berry, 1997), inter- tional approach but not the adaptationist ap- personal attraction (e.g. Graziano, Jensen- proach (Davies, 1996a). Fodor is by Dennett Campbell, Todd & Finch, 1997), pair bonding (1995) portrayed as an anti-adaptationist, adher- and mating strategies (e.g. Gangestad & Thorn- ing to Gould & Lewontin’s (1979) critique of the hill, 1997), kinship and social relations (e.g. adaptationist program, and Chomsky is reported Daly, Salmon & Wilson, 1997) as well as a more by Gould (1991) to agree with Gould’s spandrel controversial section including chapters on group theory of mind and language. The interesting selection (e.g. Wilson, 1997) . One may specu- historical situation concerning evolutionary ex- late that the lack of influence SB has had on so- planations of human behaviour or nature is that cial psychology may be due to the lack of focus these thinkers, operating outside evolutionary on social influence and contextual factors. EP is biology, largely had the choice between two ex- significantly more contextualist in its approach planations: Gould & Lewontin’s pluralism ver- (e.g. Buss & Kenrick, 1998). Evolutionary social sus Wilson’s SB. The climate at the time may psychology is a theoretical framework offering

Human Nature Review, Volume 2, 2002, 44 Human Nature Review 2 (2002) 17-61 an analysis of what mental mechanisms for proc- gies; the universal human mental-mechanisms essing social input may exist and providing a vary in phenotypic output due to varying input potential theoretical integration of social psycho- conditions. Cases where this is due to heritable logical data. traits may be called reactive heritability. 2) Fre- quency-dependent adaptive strategies (see sec- Developmental psychology. In recent years, tion V.I.). 3) Nonadaptive developmental ampli- much as a response to Piaget’s description of fication; the adaptively nonarbitrary effect of the children’s minds, and the tabula rasa point of same neurophysiological trait may affect systems view of certain behaviouristic theories, the of mental mechanisms. This latter explanation “competent infant” and child has been given offered as a critique of personality psychology; more appreciation (Trevarthen, 1980; Grieve & the patterns studied may not be adaptations. Hughes, 1990; Surbey, 1998) - the child needs to Tooby & Cosmides (1990a) advocate that one solve age-specific problems. The evolutionary start with the analysis of what survival and re- study of ontogeny, the development of the or- production problems were faced during the EEA, ganism, attempts to explain functionally, all and then search for the mechanisms, and even- stages or periods of life from conception, tual interaction between mechanisms, which ex- through early childhood, adolescence, puberty ists to solve these problems. Buss (1995a, 1996) and parenthood to senescence and death. The offers an analysis of the five-factor model based concept of “human life histories” provides a upon EP. His conclusions are that the social theoretical framework for researching life-span adaptive problems faced by humans demanded development (Low, 1998; Surbey, 1998). individual differences and that the personality Child development is within EP the study traits the five-factor model consists of both in- of how different domain-specific adaptations fluence the adaptive problems causally and inform, mature and solve problems specific for the fluences the solution to them adopted by the in- individuals ontogenetic situation (e.g. Baron- dividual. Buss (1996) argues that EP is an impor- Cohen, 1994; MacDonald, 1998, provides an tant framework for incorporating personality evolutionary approach to development from the psychology within the broader field of psychol- domain-general perspective). Adaptations are ogy. contextually dependent, but will develop nor- Anticipating the next section, the adapta- mally as long as the environmental input is ade- tionist, modular, domain-specific model of mind quate (viz. does not differ too much from the is also able to explain the lack of normal func- EEA. For discussion on this point see Scarr, tions, due to a defect in the mental mechanism 1993, 1992 vs. Baumrind, 1993). EP is now a that solves a certain function, which we concep- theoretical position being considered within tualise as personality, thus causing personality mainstream developmental psychology (Camp- disorders. This defect may occur due to muta- bell & Muncer; 1998). tions causing entropy in the mechanism’s genotype, or due to an inadequate ontogenetic envi- Personality psychology. McCrea & John (1992) ronment. This approach is adopted by Blair discussed EP’s explanation in order to overcome (1995) in a cognitive developmental investiga- the “dustbowl empiricism” of the five-factor tion of the psychopath, where the mechanism model of personality. They note that evolution- hypothesised to be lacking (or not fully devel- ary theory is better suited to explain within- oped) is the adaptation that causes social animals species similarity rather than within-species dif- to inhibit aggression toward conspecifics that ferences. This is much the point of view offered display submission cues. by Tooby & Cosmides (1990a) in their analysis of individual uniqueness and human universal nature. Covariance of personality traits within “[s]tructured systems of coordinated individual differences” (Tooby & Cosmides, 1990a, p. 60) are accounted for by three alternative explanations: 1) condition-responsive adaptive strate-

Human Nature Review, Volume 2, 2002, 45 Human Nature Review 2 (2002) 17-61 VI.II. Integrating Clinical Psychology: Evolu- former versions, due to a cultural bias toward tionary Psychopathology as a Scientist- dualism. Practitioner Perspective. The Darwinian medicine-perspective to mental disorders (or EPP) is that mental disor- “After all, nothing in medicine makes sense ex- ders are not diseases themselves; viewed within cept in the light of evolution.” from an evolutionary point of view the symp- Randolph M. Nesse & George C. Williams, toms of mental disorders are, as are cough and 1996, p. 249 fever, defences (Nesse & Williams, 1996). The predisposition for these defences evolved due to Darwinian medicine (Nesse & Williams, 1991, the increased fitness of these characters. The rea- 1996) is a new perspective to medicine and dis- son why human psychology must endure the ease, and other frailties of the human organism, pain of disorder is not due to “flaws” but “design mental disorders included. The perspective is compromises” (Nesse & Williams, 1996). In this founded on the same theoretical ground as EP: in system emotions are adaptations. They solve this case the adaptationist program and the func- survival or reproduction problems by providing tional approach, in this case, to disease. In their the organism with an informational context, and notes to the chapter on mental disorders Nesse & Nesse & Williams (1996; Nesse, 1990) willingly Williams (1996) suggest introductory reading in accept Cosmides & Tooby’s (1987) term “Dar- both SB and EP (e.g. Barkow et al., 1992), but winian algorithms of the mind” to illustrate this their analysis of evolution shows that they are inherent information-processing quality of emo- not adaptiveness-oriented, as the discrepancy tions. Nesse & Williams (1996) are critical to the between current environment and adaptations is “apparent rigor” of descriptive empirical re- a major reason for disorders; what they call “dis- search within psychiatry, as the findings are not eases of civilization” (Nesse & Williams, 1996). systemised by a “coherent theory”. Baron-Cohen (1997) edited a collection of “clas- McGuire, Marks, Nesse & Troisi (1992) sic readings in evolutionary psychopathology” argue that psychiatry’s lacking integrative para- called The Maladapted Mind (an explicit and digm may be provided by evolutionary biology. intentional echo of Barkow et al., 1992, The This does not mean that culture and personal ex- Adapted Mind), thus tying Darwinian medicine perience are unimportant factors, but that culture and EP together. So although Nesse & Williams and mind are products of evolution. Thus, an (1996, p. 233) conclude that “[t]here is every evolutionary analysis may provide a greater un- expectation that an evolutionary approach will derstanding of these phenomena. The theory is bring the study of mental disorders back to the also contextual. It considers the effect of normal fold of medicine”, there is no need to worry genetic influences, as well as the effect of ge- about the division between medicine and psy- netic anomalies, and it views the mental mecha- chology; Nesse & Williams (1996) contrast psy- nism’s function and potential malfunction from chiatry as a non-functional discipline to func- what Gilbert (1992; see also Nesse, 1987) calls tional physiological medicine - in the same way the biopsychosocial perspective. Many theoreti- EP contrasts descriptive, non-functional psycho- cians and practitioners adopt the biopsychosocial logical research against functional physiology, perspective, as it unites methods and theory following Mayr (1983) who tied the adaptation- more clearly than the concept of “eclectic”. ist program to William Harvey’s classic work on Without a theory of why the biopsychosocial the coronary system, a functional approach to the perspective is a fruitful stance it might become investigation of a system. So when Nesse & Wil- more an ideologically preferable stance than an liams in the quotation introducing this section empirical and informed theoretical perspective. rephrase Dobzhansky’s famous quote, which in- The effect of EP on clinical psychology, troduced this article, it may be rephrased specifi- EPP, may be illustrated by considering two ex- cally for EP and EPP: Nothing in psychology, amples. First, the way Freud’s psychoanalysis the understanding of psychopathology included, has been attacked and reformulated by modern makes sense except in the light of evolution. evolutionary theorists. Second, how the under- This may provoke more resistance than the two standing of anxiety from an evolutionary per-

Human Nature Review, Volume 2, 2002, 46 Human Nature Review 2 (2002) 17-61 spective has lead to a broader understanding of adaptationist thinking) in his own time, Freud’s the natural function of anxiety. Obviously other interest in evolutionary explanations of Human examples may have been presented; e.g. Stevens Nature was consistent (for an illustrative exam- & Price (1996) offer an Evolutionary Psychiatry ple see Freud, 1987). When defending the reality based on Jungian archetypes; Gilbert (1992; see of castration anxiety within the Oedipus complex also Price, Sloman, Gardner, Gilbert & Rohde, Freud (1964) refers to the “phylogenetic rein- 1994; McGuire, Troisi & Raleigh, 1997) pre- forcement” and claims: “It is our suspicion that sents a theoretically extensive analysis of the during the human family’s primeval period cas- evolutionary function of depression; and Baron- tration used actually to be carried out by a jeal- Cohen (1994), building on EP’s mental mecha- ous and cruel father upon growing boys” (p. 86). nisms, has constructed a theory of autism. It is, The only way such an anxiety could be passed alas, beyond the scope of this article to perform on would be if the anxiety of the boys that ob- an exhaustive review of EPP; such a review is served the deed (obviously not the boy “cas- recently available in McGuire & Troisi’s (1998) trated”!) was passed on through Lamarckian- Darwinian Psychiatry. The discussion included inheritance. Gould (1987b), in discussing in the two examples offered ought to illustrate Freud’s Overview of the Transference Neuroses the versatility and potential for uniting and se- claims that “Freud’s decision stems directly from lecting empirical findings and theoretical con- his commitment to an evolutionary explanation structs by adopting the EP/EPP or Darwinian of neurosis – one that would find its primary medicine stance. evidence in the theory of recapitulation” (pp. 14- 16). Thus the ontogenetic timing of a fixation Freud, the evolutionary psychologist. Web- would map onto a phylogenetic recapitulation, ster (1996), having found fault in Freud’s meta- through the adult expression of a phylogenetic theory, as well as biological and medical theory, earlier species, thus shedding light on the nature though simultaneously accepting both implicitly of the neurosis at hand. Even modern Freudians, and explicitly most of Freud’s description of or psychodynamic theoreticians, seem to be Human Nature and mind, called for a new theory hampered by Freud’s outmoded evolutionary of mind, founded on evolutionary. Criticising speculations, but still the interest for evolution- Freud has been quite common within evolutionary explanations exists. Malan (1995) refers to ary theory and EP/EPP. There may be many rea- Haeckel’s recapitulation, albeit adding the cau- sons why; most noteworthy is the fact that Freud tionary note that “Haeckel overstated his case”, 2 formulated a biological theory of Human Nature when invoking evolutionary origin of human ag- (Sulloway, 1979/1992), based mainly on the re- gression (pp. 212-215), and several other phe- jected biological theories of recapitulation, nomenon. Malan is as such an evolutionary psy- which is “[t]he repetition of ancestral stages in chologist too (though not an EP, as defined in embryonic or juvenile stages of descendants” this article). Consider the following quote by (Gould, 1977b, p. 485), and Lamarckian- Malan (1995, p. 63) on the Oedipus complex and inheritance (Sulloway, 1979/1992; Webster, evolution: 1996; Gould, 1977b, 1987b). One may defend calling Freud an evolutionary psychologist. Al- The observation that, even when the fa- though his evolutionary theoretical foundation ther is weak or absent, male patients tend was quite different from EP’s, and even out- to have a fantasy of a powerful and pun- moded (or at least less popular; see Gould, ishing father, forces one into thinking se- 1987b, who also offers a critical view of Freud’s riously about theories involving evolution. This is one of the many examples of 2 the way in which psychoanalysis pro- I acknowledge the distinction between “psychoanalytic” vides evidence about the evolution of and “psychodynamic” often adopted, but will in this chapter use these terms as synonymous to “Freudian”, human beings – a link between two areas which is all theory based upon Freud’s original that has been very little explored, and observations of Human Nature, but excludes theories that needs to be explored in collaboration do not accept innate motivational drives. The authors, cited in this chapter, neither make this distinction.

Human Nature Review, Volume 2, 2002, 47 Human Nature Review 2 (2002) 17-61 with scientists familiar with modern theo- Lloyd (1992) present two, somewhat different, ries. EP/EPP approaches to making these necessary corrections to the theory. Obviously the above example shows the lack of Badcock (1998) avoids almost all critique “modern theories” within Malan’s (1995) own of Freud. Rather he attacks the SSSM’s “de- evolutionary thinking. Adding to the recapitula- biologized” interpretation of Freud and advo- tion-inspired account of aggression, Malan cates the original, biological understanding as (1995) now offers a Lamarckian account of the intended by Freud. Badcock (1998) quotes Freud Oedipus complex that mirrors Freud’s phyloge- “who denounced those who ‘have picked out a netic cause cited above. One may add that the few cultural overtones from the symphony of life kind of research Malan (1995) is calling for is and have once more failed to hear the mighty being pursued and has borne interesting results and primordial melody of the instincts’” (p. 458). (e.g. see Gazzaniga’s [1992] account of Daly & It is worthwhile noting that Gould (1987b) advo- Wilson’s empirical research). cates the same approach to understanding Freud, Gazzaniga (1992), in his chapter Selec- in order to argue against Freud’s recapitulary, tion Theory and the Death of Psychoanalysis, Lamarckian-inheritance and adaptationist claims starts by describing how several psychoanalytic within a biological rather than metaphorical theories, in which Freud’s ideas were taken to framework. Badcock (1998) thereafter reinter- extremes, have been proven wrong, and urges prets Freud in a modern Darwinian light, having psychoanalysis to become scientifically stringent noted that although Freud has been criticised for and biologically compatible. Gazzaniga (1992, p. arguing for Lamarckian-inheritance this is a 160) quotes Freud: “’the shortcomings of our charge of which Charles Darwin was also guilty. (the psychoanalysts’) description would proba- The theoretical drive of Badcock’s (1998) argu- bly vanish if we were already in a position to ment lies in pointing out how modern evolution- replace the psychological terms by physiological ary theory, even the Dawkinsian gene-level per- or chemical ones… Biology is truly a land of spective, may be not only be compatible with unlimited possibilities.’” Gazzaniga’s (1992, pp. Freud’s theories, but, as Badcock (1998, p. 458) 175-177) conclusion is that psychodynamic claims, that: processes are “rampant”: Indeed, it is the argument here that, They are the result of the simple intro- whatever his own misconceptions may duction of a special capacity of the hu- have been, Freud’s findings can only be man brain, the capacity to make volun- understood in terms of advances in genet- tary expressions, which, in turn, allows ics and evolution that were not to take for deception and the hiding of inten- place until he had been dead for some tions. This capacity can, however, decades. quickly compound, resulting in complex psychological states. From this view- An example of this is how Trivers’ (1972) theo- point, selection theory gives us a rich ries on differential parental investment may ex- way of thinking about how we humans plain conflict, at the interpersonal or between- have developed the complex psychologi- gender level, at the intrapsychic level (see also cal processes we commonly enjoy. Gazzaniga, 1992; Nesse & Lloyd, 1992 above) and also at the intragenomic level (Badcock, Gazzaniga’s (1992) position is equivalent to that 1998; see also section V.I). This is obviously an of Webster (1996); the meta-theory is false due interesting perspective, but one may also ques- to outmoded theories of biology and lack of sci- tion the validity of the inference of the validity entific stringency, but many observations and the of Freud’s concept of “bisexuality” based on the psychodynamic formulations of Human Nature fact that the X-chromosomes are present in both may be true, and deserve the modern scientific genders. In addition, inferring what Freud may and evolutionary foundation Freud was incapa- have believed about evolution “had he been alive ble of providing. Badcock (1998) and Nesse & today” (Badcock, 1998, p. 462), is an unneces-

Human Nature Review, Volume 2, 2002, 48 Human Nature Review 2 (2002) 17-61 sary and simplistic speculation. There is a certain some psychoanalytic discoveries” (Nesse & eagerness in Badcock’s (1998) defence and rein- Lloyd, p. 603). Attempting to overcome the for- terpretation of Freud’s evolutionary insights. mer obstacle is justified by the claim that “psy- This may fruitfully be tempered by accepting choanalytic methods can, nonetheless, provide a Freud’s theories more as inspiration to guide unique window on high levels of mental organi- modern EPP and EP research within areas where zation” (Nesse & Lloyd, p. 602). One might add there is reason to believe that further research is that the process of having psychoanalysis and EP warranted, rather than as truths to be vindicated inform each other ought to result in a more rig- by EPP and EP. orous conceptualisation and operationalised Nesse & Lloyd (1992, p. 601) introduce definitions. Nesse & Lloyd pass the latter obsta- their analysis of the evolution of psychodynamic cle by connecting the “repugnance” of psycho- mechanisms by making the following integrative analytic findings to the similar reaction to the claim: evolutionary work by e.g. Dawkins (1976/1989, 1982). Nesse & Lloyd (1992, p. 603), as This converging focus on human infor- Badcock (1998), then build upon Trivers’ (1971, mation-processing mechanisms may give 1972, 1985) work. They quote Trivers’ comment new significance to psychodynamics. in the foreword to the American edition of Cognitive and evolutionary psychologists Dawkins’ The Selfish Gene: “’the conventional may find in psychodynamics careful de- view that natural selection favours nervous sys- scriptions of traits that may closely match tems which produce ever more accurate images the functional subunits of the mind that of the world must be a very naïve view of mental they are seeking. Psychodynamic psy- evolution.’” They justly add that Trivers did not chologists and psychiatrists may find in explicitly connect his hypothesis with psycho- evolutionary psychology new possibili- analysis. Nesse & Lloyd (1992) thus focus on ties for a theoretical foundation in biol- self-deception and repression as major traits of ogy. both psychoanalytic and evolutionary theory of Human Nature, as well as the modularity of the A “functional subunit” is an adaptationist formu- traits focused within psychoanalysis. lation that implies that psychodynamic mecha- The most important benefit to psycho- nisms are equivalent to EP’s evolved domain- analysis from an integration with EP is “the pos- specific mental mechanisms. Also it is worth- sibility of a solid theoretical foundation in the while noticing the need to found the psycho- natural sciences” (Nesse & Lloyd, 1992, p. 618). dynamic theory of Human Nature in biology. This is the same point made by Symons (1987), This was Freud’s original position (Sulloway, Tooby & Cosmides (1992) and Buss (1995) 1979/1992; Badcock, 1998), and made it theo- about psychology proper, and which was the retically possible to infer human universals from original goal of Freud (Sulloway, 1979/1992). a limited sample of observations (much on a par Nesse & Lloyd (1992) claim that consistency with Piaget’s work and biological underpinnings; with evolutionary theory is the first test for any founded on the idea that ontogeny recapitulates level of psychoanalytic hypothesising. Com- phylogeny, though Piaget denied influence by menting on the similarity of psychoanalytic re- Haeckel’s evolutionary theory [Gould, 1977b]). ports of phenomena and early ethological inves- Nesse & Lloyd (1992) admit that Freud’s tigations, Nesse & Lloyd (1992, p. 620) con- evolutionary ideas (they add group selectionism clude: “The systematic application of evolution- to the list) are an obstacle to integrating psycho- ary principles has transformed ethology into a dynamic theory with EP, but they view the ulti- mature science; perhaps it can do the same for mate, functional, biological perspective Freud’s psychoanalysis. If so, psychoanalysts will some- theoretical forte. Other obstacles would be the day be recognized as pioneering naturalists of “justified” critique of the difficulty of disentan- the mind.” This would demand a shift from the gling “empirical observations from the complex SSSM interpretation of psychoanalysis. theory in which they are often embedded” The integrative, rigorous nature of EP (Nesse & Lloyd, p. 602), and the “repugnance of and EPP is such that one may use the perspective

Human Nature Review, Volume 2, 2002, 49 Human Nature Review 2 (2002) 17-61 to discipline other bodies of theory. Whether ity in conditioning phobic responses to stimuli one’s point of departure is that Freud or Freudi- was false. Some cues could be conditioned to ans are correct or not is not as interesting as give phobic reactions with greater ease than whether one, by adopting the EP/EPP stance, other stimuli, and with longer lasting effect. The may provide a theoretically and empirically valid stimuli that were potentially phobic were cues framework for evaluating theory and data within that were potential dangers in our EEA. This ap- fields as seemingly separate as cognitive science proach was necessary in order to explain Öhman and psychoanalysis. The feat of EP lies in pro- et al.’s (1976) results. These classic findings of viding an integrative framework. Even if “some learning psychology illustrate lucidly the inter- of The Adapted Mind’s editors share [the] con- dependency between environment and organism. cerns” that psychodynamic theory is “a tangle of For further elaboration on the interaction be- vague concepts and inconsistently defined phe- tween learning and domain-specific, adaptation- nomena” (Barkow et al., 1992, p. 600) – the ist biological preparedness, see section V.III. work cited above indicates that their theory may Nesse (1987), presenting an evolutionary untangle and bring consistency to psycho- perspective on panic order and agoraphobia, dynamic theory. claims that panic is an adaptation - a normal defence-reaction with the evolved function to make Anxiety, as adaptive defence - not disease. the organism escape threatening situations. Es- Nesse & Williams (1996) criticise the common caping these situations and learning what situa- psychiatric understanding of anxiety, which tions are threatening provides a survival advan- holds that anxiety is a disease in itself, capable tage. Panic disorder is therefore the occurrence of being divided into distinct types. They would of normal defence-reactions in the absence of rather view anxiety as a defence, an adaptation real threat. Nesse (1987) claims that this attitude governing the organism’s response to a contex- is a benefit not only to understanding panic dis- tual cue. These contextual cues will - most often orders, but also in facilitating a positive thera- - be phenomena found in our phylogenetic past, peutic alliance. The added understanding the very rarely a novel danger. When one has an evolutionary perspective brings, and other theo- anxiety reaction to a phyletic new cue, it will ries can not, is, according to Nesse (1987), the usually be to a quality of that cue that was found ability to explain the anxiety symptoms that con- in our EEA (e.g. claustrophobia might be a better stitute the agoraphobia syndrome, the specific label for most cases of Fear of Flying). factors that reduce anxiety, and the fact that re- The need for contextual input into innate, peated panic attacks often lead to agoraphobia. domain-specific information processing mecha- Exposure therapy will provide information that nisms - the learning instincts - regulate anxiety- the situations are not threatening, yet an exclu- responses, too. Mineka, Davidson, Cook & Keir sive behavioural approach will offer merely a (1984) found that fear in primates could arise partial explanation of the disorders aetiology. due to observational learning, noting the “strik- Nesse (1987) advocates the integration of psy- ing […] rapidity with which the fear was ac- chological, social and biological treatment of quired” (p. 369). Mineka et al. (1984) conclude panic disorder and agoraphobia, but warns that that such rapidity is a necessity given an ultimate removing the natural defence-reaction may be functional interpretation of the fear-response and harmful. Marks & Nesse (1994) share this per- context; if you do not learn the fear fast you spective to anxiety disorders in general; “hypo- might not survive the next cue-exposure. The phobia-disorder” would be the lack, e.g. due to same preparedness and rapidity, but with a dif- medication, of natural defensive reactions to ferent, or domain-specific, defence-response, threatening situations. Marks & Nesse (1994) was noted by Garcia & Koelling (1966); the ul- adopt Cosmides & Tooby’s (1987) Darwinian timate functional reason why the domain- algorithms to explain the domain-specific infor- specific conditioning must occur after such lim- mation processing involved in different specific ited exposure to the cue, and be long lasting, is threats and responses to avert these. The evolu- similar. Öhman et al. (1976) found that the pre- tionary perspective explains why we have anxi- dominant behaviouristic theory of equipotential- ety responses to archaic threat cues, rather than

Human Nature Review, Volume 2, 2002, 50 Human Nature Review 2 (2002) 17-61 more real dangers of our modern world (Marks than subjectively perceived pragmatic value). & Nesse, 1994; Öhman et al., 1976). Thus the result is a refreshing open-mindedness Anxiety, as a natural defence response, to different theories and a theoretically governed with a genetic basis (Marks, 1986), whose varia- eclecticism, rather than the far too common section may be due to genetic defects or normal tarianism or con amore or ad hoc eclecticism. EP variation (Nesse & Williams, 1996), and an and EPP may hone existing theory by providing adaptive function, is obviously an evolutionary selection criteria for theories, while simultane- phenomenon. This does not imply that it is im- ously allowing for a theoretically guided integra- possible to treat, or even more difficult than if it tive approach by adding an analysis at several was defined differently. On the contrary, anxiety levels; such as ultimate, proximate, neurocogni- thus defined becomes more available for analysis tive, psychophysiological, learning, psycho- and intervention at several levels due to the bi- dynamic, social-psychological, cultural etc., opsychosocial-perspective. The integration with which may be summed up as the biopsychoso- cognitive-behavioural theory and therapy is al- cial-perspective. most self-evident (see section V.III). One must Baron-Cohen (1997b) describes how EP identify danger cues and, through exposure, re- may contribute to the understanding and study of move their information as danger signals (Marks, psychopathology: “First the universal, adaptive, 1986; Kanfer & Philips, 1970; Rescorla, 1988), neurocognitive mechanism must be identified in but with the addition of an ability to ask ultimate its healthy state, and only then can its breakdown questions and explain “why”, opening a vista for be studied and its link to pathology explored” (p. new research (Marks & Nesse, 1994; Nesse, XI). But Baron-Cohen (1997b) also claims that 1987), instead of merely describe “how”. EPP may inform EP: “It also happens that a uni- The two examples above, the evolution- versal, adaptive, neurocognitive mechanism is ary approach to both the theory of Freud and the first revealed by its breakdown” (p. XI). One mental disorder anxiety, illustrate two points. may overlook a mechanism when the mind is First, a psychological theory, even one that is not functioning normally, but when an anomaly usually accepted as scientific within mainstream causes the system to malfunction, one becomes psychology, may be given a frame of reference aware of the “crucial mechanism at work” (p. and a set of basic principles from which to XI). This is similar to Cosmides & Tooby’s evaluate itself. The result being greater commu- (1994a) critique of “instinct-blindness” within nicability of findings and ideas with mainstream cognitive psychology. Research too often fo- science at several levels of analysis. Second, a cuses on what we have difficulties in perform- mental disorder may be reformulated in more ing, but not what we do naturally and efficiently; psychological valid terms, i.e. independently of which may reveal a lot more about our mental the typical “medical model”, while still accept- architecture. able from a biological perspective, and even gaining new approaches to understanding and VII. Conclusions levels of analysis. Gilbert (1992), though focusing primarily Some worry that EP is just a new example of on depression, provides an excellent example of sectarianism within the science of psychology. the theory’s potential. The evolutionary perspec- Others (e.g. Buss, 1995a, 1995b) herald it as a tive does not specify a method of treatment, but new paradigm of psychology, which is compati- may provide theories for understanding the dis- ble with Nesse & Williams (1996) and McGuire order and a framework for evaluating what et al. (1992) claims about EPP. A response to the methods and other theories may be worthwhile former is that a theory that pretends to collect the implementing or adopting. Gilbert (1992) pre- dustbowl empiricism of psychological science sents and evaluates an array of major theories of within a common framework, which also will depression, from Freud’s Psychoanalysis to allow for communication with other levels of Beck’s Cognitive Theory, and has at his disposal scientific analysis relevant to a life science, does a framework that allows him to make informed not fulfil the criteria for sectarian. La Cerra & theoretical decisions (based on other information Kurzban (1995) provide a cogent response to the

Human Nature Review, Volume 2, 2002, 51 Human Nature Review 2 (2002) 17-61 second claim; one cannot have a ”new” para- B. Crawford & D. L. Krebs (Eds.), digm where there has been no unifying theory. Handbook of evolutionary psychology. The conclusion this article reaches, based on the Ideas, issues and applications (pp. 457- presented arguments, is that EP may be a contri- 483). Mahwah, NJ: Lawrence Erlbaum bution to psychological science at several differ- Associates. ent, important levels. First, EP allows psychologists to communicate between different areas of Bailey, J. M. (1998). Can behavior genetics con- psychological interest, and with other branches tribute to evolutionary behavioral sci- of science relevant to psychology as a life science. In C. B. Crawford & D. L. Krebs ence. Second, EP provides a well-researched, (Eds.), Handbook of evolutionary psy- rigorously formulated theory for evaluating any chology. Ideas, issues and applications other psychological theory. The theory may pre- (pp. 211-233). Mahwah, NJ: Lawrence vent one from suggesting abilities that could not Erlbaum Associates. evolve but have been suggested within almost all Barkow, J. H., Cosmides, L. & Tooby, J. (Eds.). psychological disciplines. The versatility EP (1992). The Adapted Mind: Evolutionary shows as a theoretical framework for disciplines psychology and the generation of culture. as different as psychoanalysis and cognitive sci- New York: Oxford University Press. ence, suggests that EP may succeed in integrating psychological science. It also supports the Baron-Cohen, S. (1994). How to build a baby claim that EP is as theoretically valid a science that can read minds: cognitive mecha- as cognitive science and evolutionary biology. nisms in mindreading. Cahiers de Psy- EP also brings to psychology the focus on a chologie Cognitive/ Current Psychology theoretically rigorous and predictive theory of of Cognition, 13, 513-552. Human Nature, and the functional approach, which may provide maturation from the level of Baron-Cohen, S. (Ed.). (1997a). The maladapted mere descriptive science. At the level of generat- mind: Classic readings in evolutionary ing new theories and insights about Human Na- psychopathology. Hove, UK: Psychology ture, EP seems to have proven its worth. Press. This article therefore concludes that EP offers the most promising and likely unifying Baron-Cohen, S. (1997b). Preface: Why evolu- paradigm for psychological science available tionary psychopathology? In S. Baron- today. An appreciation of the versatility of EP, Cohen (Ed.), The maladapted mind: from a scientist-practitioner perspective, sup- Classic readings in evolutionary psycho- ports this conclusion. EP’s ability to convince pathology (pp. ix-xiii). Hove, UK: Psy- mainstream psychology of the possibility and chology Press. need to found its constructs and concepts on evo- Bateson, P. (1986). Sociobiology and human lutionary valid ground will facilitate this shift. politics. In S. Rose & L. Appaganesi (Eds.), Science and beyond. (pp. 79-99). Leif Edward Ottesen Kennair, Psychologist, Oxford, UK: Blackwell. Nordfjord Psychiatric Centre, 6770 Baumrind, D. (1993). The average expectable NORDFJORDEID, Norway. environment is not good enough: A re- E-mail: [email protected] sponse to Scarr. Child Development, 64, 1299-1317. References Betzig, L. (1998). Not whether to count babies, Axelrod, R. (1984). The evolution of coopera- but which. In C. B. Crawford & D. L. tion. Harmondsworth, UK: Penguin. Krebs (Eds.), Handbook of evolutionary psychology. Ideas, issues and applica- Badcock, C. R. (1998). PsychoDarwinism: The tions (pp. 265-273). Mahwah, NJ: Law- new synthesis of Darwin and Freud. In C. rence Erlbaum Associates.

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