Copyrighted material – 9781137348005 Brief Contents

Part I Historical and Methodological Issues 1 1 Historical Introduction: and Theories of Mind and Behaviour, Darwin and After 3 2 Foundations of Darwinian Psychology 17 Part II Two Pillars of the Darwinian Paradigm: Natural and Sexual Selection 33 3 Natural Selection, Inclusive Fitness and the Selfish Gene 35 4 Sex and Sexual Selection 50 Part III Human Evolution and its Consequences 69 5 The Evolution of the Hominins 71 6 This Quintessence of Dust: The Hominin Package 87 Part IV and Developmental Plasticity 109 7 Adaptations and Evolved Design 111 8 Life History Theory 138 Part V Cognition and Emotion 163 9 Cognition and Modularity 165 10 Emotions 190

Part VI Cooperation and Conflict 203 11 and Cooperation 205 12 Conflict and Crime 229 Part VII Mating and Mate Choice 253 13 Human Sexual Behaviour: Anthropological Perspectives 255 14 Human Mate Choice: The Evolutionary Logic of Sexual Desire 268 15 Facial Attractiveness 293 16 The Paradox of Homosexuality 312 17 Incest Avoidance and the Westermarck Effect 323

Part VIII Health and Disease 339 18 Darwinian Medicine: Evolutionary Perspectives on Health and Disease 341

v

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005 vi Brief Contents

19 Three Case Studies in Evolution and Health: Diet, Cancer and Mental Disorders 371

Part IX Wider Contexts 397 20 The Evolution of Culture: Genes and Memes 399 21 Ethics 418

Glossary 435 References 447 Index 484

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005 Historical Introduction: Evolution and Theories chapter of Mind and Behaviour, Darwin and After 1

In the distant future I see open fields for far more important researches. The origin of 4 Psychology will be based on a new foundation, that of the necessary The study of animal behaviour: ­acquirement of each mental power and capacity by gradation. Light will be and comparative thrown on the origin of man and his history. ­psychology in the 20th century 5 (Darwin, 1859b, p. 458) The rise of and 10 Summary 14 Further reading 15

Charles Darwin published his two greatest books on inadequately informed by selectionist thought. Had evolutionary theory, by Means Freud better understood Darwin, for example, the of Natural Selection, and The Descent of Man and Selec- world would have been spared such fantastic dead-end tion in Relation to Sex, in 1859 and 1871 respectively, notions as Oedipal desires and death . (Daly, and he was convinced that a revolution in psychol- 1997, p. 2) ogy would shortly follow. But for the first three-­ quarters of the 20th century, while became The project of Darwinising humanity, however, more securely based on deepening evolutionary is not just an activity taking place inside the disci- foundations, psychology failed lamentably to exploit pline of psychology: it is to be found in, and draws the potential of Darwinian thought. There were some upon, a whole range of academic fields such as ani- exceptions – William James being the most notable – mal behaviour, behavioural , physical and but many psychologists either ignored or, cultural anthropology, and medicine. This more damagingly, misunderstood the message that it book takes a broad-based and catholic approach to held. Psychology was poorer as a result. this enterprise and draws upon these diverse fields Borrowing the terminology of Thomas Kuhn as required. (1962), we might say that for most of its history psy- Darwinism began in 1859 when Darwin chology has lacked a unifying paradigm – a set of (Figure 1.1), in his fiftieth year, finally published procedures, assumptions, methodologies and back- his masterwork On the Origin of Species by Means ground theories that all its practitioners can agree of Natural Selection. The book, originally intended upon. There are those who would argue that evolu- as an abstract of a much larger volume, contained tionary psychology has the potential to supply this concepts and insights that had occurred to Darwin missing paradigm, and this book is partly an attempt at least 15 years earlier, yet he had wavered and to explore the strength of this claim. This belief is delayed before publishing. The larger volume neatly summarised by the late Margo Daly: never appeared, and Darwin was forced to rush out his Origin following a remarkable series of The reason why psychologists have wandered down events that began in June of the previous year. It is so many garden paths is not that their subject is 1858, therefore, that serves as a convenient start- resistant to the scientific method, but that it has been ing point.

3

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

4 Evolution and Human Behaviour

1.1 the origin of species After the Linnean meeting, Darwin set to work on what he thought would be an abstract of the great On 18 June 1858, Darwin received a letter from a volume he was working on. The abstract grew to a young naturalist called , then full-length book, and his publisher, Murray, even- working on the island of Ternate in the Malay Archi- tually persuaded Darwin to drop the term ‘abstract’ pelago. When Darwin read its contents, he felt his from the title. After various corrections, the title was world fall apart. In the letter was a scientific paper in pruned to ‘On the Origin of Species by Means of the form of a long essay entitled ‘On the tendency of Natural Selection’, and Murray planned a print run varieties to depart indefinitely from the original type’. of 1,250 copies. Wallace, innocent of the irony, wondered whether Darwin, amid fits of vomiting, finished correct- Darwin thought the paper important and ‘hoped the ing the proofs on 1 October 1859. He then retired idea would be as new to him as it was to me, and that for treatment to the Ilkley Hydropathic Hotel in it would supply the missing factor to explain the ori- Yorkshire. In November, Darwin sent advance copies gin of species’ (Wallace, 1905, p. 361). The ideas were to his friends and colleagues, confessing to Wallace far from new to Darwin: they had been an obsession his fears that ‘God knows what the public will think’ of his for half a lifetime. Wallace had independently (Darwin, 1859a). Many of Darwin’s anxieties were arrived at the same conclusions that Darwin had unfounded. When the book went on sale to the trade reached at least 14 years earlier, and the demonstra- on 22 November, it was already sold out. It was an tion of which Darwin saw as his life’s work. Darwin instant sensation, and a second edition was planned knew that the essay must be published and, in a mis- for January 1860. Thereafter, man’s place in nature erable state, exacerbated by his own illness and fever was changed, and changed utterly. in the family, wrote for advice to his geologist friend and scientific colleague Sir , comment- ing that he ‘never saw a more striking coincidence’ and lamented that ‘all my originality, whatever it may amount to, will be smashed’ (Darwin, 1858). Fortunately for Darwin, powerful friends arranged a compromise that would recognise the importance of Wallace’s ideas and simultaneously acknowledge Darwin’s previous work on the same subject. A joint paper, by Wallace and Darwin, was to be read out before the next gathering of the Linnean Society on 1 July 1858. The reading was greeted by a muted response. The president walked out, later complaining that the whole year had not ‘been marked by any of those striking discoveries which at once revolutionise, so to speak [our] department of science’ (Desmond and Moore, 1991, p. 470). At his home, Down House, Darwin remained in an abject state, coping with a mys- terious physical illness that plagued him for the rest of his life and nursing a nagging fear that it might seem as if he had stolen the credit from Wallace. He was also grieving: his young son Charles Waring had died a few days earlier. As the Linnean meeting proceeded, Darwin stayed away and attended the funeral with his wife Emma. By the end of the day, the theory of evolu- Figure 1.1 (1809–82) from a tion by natural selection had received its first public ­photograph taken by Maull and Fox around 1854. announcement, and Darwin had buried his child. Source: Public domain Wikimedia Commons.

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

1 Evolution and Theories of Mind and Behaviour, Darwin and After 5

1.1.1 New foundations the analogy between animals and humans in both directions. Animals could be understood using con- In On the Origin, Darwin was decidedly coy about the cepts drawn from the mental life of humans, and this application of his ideas to humans, but the implica- understanding could then be reapplied to understand tions were clear enough and, in the years following, the human condition. Lorenz frequently expressed both Darwin and Thomas Huxley began the process his debt to Heinroth’s approach. of dissecting and exposing the evolutionary ancestry By conducting experiments at his home on the and descent of man. It was towards the end of On the outskirts of Vienna, Lorenz observed numerous fea- Origin, however, that Darwin made a bold forecast tures of animal behaviour that have become associ- that psychology would be placed on a new founda- ated with his name. In one classic study, he noted tion and that light would be thrown on the origin of how a newly hatched goose chick will ‘imprint’ itself man and his history (Darwin, 1859b, p. 458). On the on the first moving object it sees. In some cases, this origin of man, Darwin was right, and light continues was Lorenz himself, and chicks would follow him to be thrown with each new fossil discovery. On psy- about, presumably mistaking him for their mother. chology, the new foundation that Darwin foresaw has Lorenz stressed the importance of comparing the been slow in coming. Over the past 20 years, how- behaviour of one species with another related one ever, there have been signs that a robust evolution- and argued for the importance of understanding ary foundation is being laid that promises to sustain a evolutionary relationships between species. In this thoroughgoing Darwinian approach to understanding respect, Lorenz unashamedly drew parallels between human nature. The bulk of this book is about those the behaviour of humans and other animals. In his foundations. It is fair to say, however, that initially most popular work, King Solomon’s Ring, for example, evolutionary principles were most successfully applied he suggested that the ‘war dance of the male fighting to the study of the behaviour of non-human animals. fish… has exactly the same meaning as the duel of words of the Homeric heroes, or of our Alpine farm- ers, which, even today, often precedes the traditional 1.2 the study of animal behaviour: Sunday brawl in the village inn’ (Lorenz, 1953, p. 46). ethology and in the 20th century

A number of disciplines have laid claim to provid- ing an understanding of animal behaviour, includ- ing ethology, comparative psychology, behavioural ecology and, emerging in the 1970s, sociobiology. The problem for the historian is that these terms were not always precisely defined and the disciplines frequently overlapped. It is appropriate, therefore, to consider the origins of comparative psychology and ethology together.

Figure 1.2 (1907–88) (left) 1.2.2 ethology 1900–70 and (1903–89) (right), photograph taken about 1978. One of the giants of 20th-century ethology was the Konrad Lorenz and his Dutch colleague Nikolaas Tinber- gen helped to found the science of ethology. Austrian Konrad Lorenz (Figure 1.2). Lorenz origi- Source: Wikimedia Commons (http://commons.­ nally trained as a doctor but was influenced by the wikimedia.org/wiki/File:Lorenz_and_Tinbergen1.jpg, work of Oscar Heinroth at the Berlin Zoological Gar- accessed 16 December 2015). Reproduced with kind dens on the behaviour of birds. Heinroth exploited permission of Riccardo Draghi-Lorenz.

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

6 Evolution and Human Behaviour

One of Lorenz’s early concepts was that of the of the same species, a subject now of great interest , which referred to a pattern of to behavioural ecologists. Burkhardt suggests that behaviour that could be triggered by some external this neglect of intraspecific variation in behav- . Using a term that was later to prove so trou- iour was partly a reflection of the fact that Lorenz blesome for ethology, Lorenz regarded these action wished to distance himself from animal psycholo- patterns as ‘instincts’ forged by natural selection and gists and their work on captive animals. Lorenz common to each member of the species. Fixed action distrusted inferences from laboratory and domes- patterns have the following characteristics: ticated animals on aesthetic grounds and also as a consequence of his concern that captive animals l Their form is constant: that is, the same sequence showed too much variability in the behaviours of actions and the same muscles are used they had learned. This variability was, to Lorenz, a l They require no hindrance (Burkhardt, 1983). l They are characteristic of a species It was one of Lorenz’s students, Nikolaas l They cannot be unlearned Tinbergen (1907–88), who finally completed the l They are released by a stimulus. establishment of ethology as a serious scientific dis- cipline (Figure 1.2). Tinbergen joined Lorenz in 1939 Evidence of a fixed action pattern that is often cited and helped to develop methods for studying behav- is the observation that a female greylag goose (Anser iour in the wild. In 1949, he moved to and anser) will retrieve an egg that has rolled outside her led a research group dedicated to the study of ani- nest by rolling it back using the underside of her bill. mal behaviour. Tinbergen studied how fixed action Lorenz noticed that this action continued even when patterns interact to give a chain of behavioural the egg was experimentally removed once the behav- reactions. In his classic study of the , iour had begun. Once it started, the behaviour had Tinbergen (1952) showed how, during the courtship to finish whether it was effective or not. The stimuli ritual, males and females progress through a series of that trigger fixed action patterns became known as actions in which each component of female behav- sign stimuli or, if they were emitted by members of iour is triggered by the preceding behaviour of the the same species, releasers. An interesting example is male, and vice versa, in a cascade of events. The cul- to be found in the behaviour of the European robin mination of the sequence is the synchronisation of (Erithacus rubecula), documented by the British orni- gamete release and fertilisation. thologist David Lack in the 1940s. Lack showed that Both Tinbergen and Lorenz developed mod- the releaser for male aggression in this species is the els to conceptualise the patterns of behaviour they patch of red found on the breast of the bird. A male observed. Lorenz interpreted his observations as con- robin will attack another male that it finds in its ter- sistent with a psycho-hydraulic model, sometimes ritory, but it will also attack a stuffed dead robin and called, somewhat disparagingly, the flush toilet even a tuft of red feathers (Lack, 1943). model. If behaviour is interpreted as the outflow of Once the essence of the stimulus has been iden- water from a cistern, the force on the release valve tified, it becomes possible in some cases artificially can be interpreted as the trigger. The model was to exaggerate its characteristics and create supernor- more sophisticated than suggested by its comparison mal stimuli. If a female oyster catcher (Haemotopus with a domestic flush toilet, but its essential feature ostralegus), for example, is presented with a choice was the accumulation of ‘action-specific energy’ in a of egg during incubation, she will choose the larger. manner analogous to the accumulation of a fluid in Even if an artificial egg twice the size of her own is a cistern. Sigmund Freud employed similar hydraulic introduced, the oyster catcher still prefers the larger metaphors in his thinking about drives and repres- one, even though common sense (to an outsider) sion. Despite their obvious shortcomings as accurate would indicate that it is unlikely to be an egg actu- analogues of mental mechanisms, they are still com- ally laid by the bird. monplace in everyday speech. To ‘explode with rage’ Lorenz had little interest in the individual vari- or ‘let off steam’ are both echoes of the type of mod- ation of instincts displayed by different members els utilised by Lorenz and Freud.

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

1 Evolution and Theories of Mind and Behaviour, Darwin and After 7

Tinbergen developed an alternative model that, or do they have to learn some components from a while retaining the concept of accumulating energy parent or an older bird? These questions belong to that drives behaviour, suggested a hierarchical organ- Tinbergen’s second category dealing with the devel- isation of instincts that are activated in turn. The opment and of behaviour. models of Lorenz and Tinbergen met with much sub- We could also ask about the evolution of the sequent criticism. It proved difficult, for example, to behaviour to its present form. Is the behaviour found correlate the features of the model with the growing in related species? If so, has it been acquired by descent body of information from neurobiology about real from a common ancestor? A particular question con- structures in the brain. cerns why even Canadian and Asian wheatears travel One of Tinbergen’s most lasting contributions to Africa. If the aim is simply to move south, those was a clarification of the types of question that ani- in Canada and Asia could save themselves thousands mal behaviourists should ask. In 1963, in a paper of miles of travel. Is the move to Africa by the new called ‘On the aims and methods of ethology’, populations outside Europe a ‘hangover’ from when Tinbergen suggested that there were four ‘whys’ of the wheatear only lived in Europe? These questions animal behaviour: refer to the evolutionary origin of the behaviour as raised in the third ‘why’ question above. 1. What are the mechanisms that cause the behav- Finally, in relation to the movement to Africa, iour? (causation) we could ask questions about ultimate causation. 2. How does the behaviour come to develop in the Why do birds make such arduous and perilous jour- individual? (development or ontogeny) neys? How does flying to Africa increase the sur- 3. How has the behaviour evolved? (evolution) vival chances of those making the journey? It must 4. What is the or survival value of the carry some advantage over not moving, otherwise a ­behaviour? (function) mutant that appeared and did not fly away would leave more survivors, and non-migration would It has been noted that a useful mnemonic for these gradually become the norm. The type of answer is ‘ABCDEF: Animal Behaviour, Cause, Development, given to this last functional ‘why’ of Tinbergen Evolution, Function’ (Tinbergen, 1963). would presumably show that the benefits of trav- To appreciate the application of these questions, elling in terms of food supply and then securing a it may be useful to consider an example. In many mate outweigh the drawbacks in terms of risks and areas of the northern hemisphere, birds fly south as energy expenditure. Ultimately, we would have to winter approaches. One such species is the wheatear show that migrating is a better option than staying (Oenanthe oenanthe). Wheatears migrate to Africa in in one place as a means of leaving offspring. We will the winter even though some groups have moved then have demonstrated the function or adaptive from their European breeding grounds and have significance of the behaviour. established new populations in Asia and Canada. We Taking an overview of Tinbergen’s four ‘whys’ as could ask of this behaviour: What triggers flocks to a broad generalisation, psychologists (dealing with take to the air? How do they ‘know’ when the time humans or animals) have tended to be interested arrives to depart and which way to fly? These ques- in the ‘whys’ of proximate causation and ontogeny, tions address the proximate causes of the behaviour and less interested in questions about evolution and and relate to Tinbergen’s first question of causation. adaptive significance. The growth of sociobiology The answer lies in specifying the physiological mech- and evolutionary psychology is a direct attempt to anisms that are activated by environmental cues, reverse this trend and supply a unifying paradigm for possibly day length, temperature, angle of the sun the behavioural sciences based on the understand- and so forth. ing of ultimate causation and evolutionary function Probing further, we could ask how the ability to (Barkow et al., 1992). fly over such vast distances in a species-typical man- The work of Lorenz and Tinbergen is usually ner is acquired by an individual. Do animals know classified as being central to the tradition of classical instinctively which way to fly and how far to travel, ethology. Classical ethology was forced to adjust its

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

8 Evolution and Human Behaviour

ground as a result of telling criticisms that appeared 1.2.2 comparative psychology 1900–70 in the 1950s and 60s from comparative psycholo- gists and, to be fair, discoveries by the ethologists An early exponent of the methods that came to be themselves. Lehrman (1953), in particular, was associated with comparative psychology was Ivan a forceful critic of the use of the term ‘innate’ in Petrovich Pavlov (1849–1936). Pavlov, the son of a ethology. The attempt to classify behaviour as either priest, began his career studying medicine, and was innate or learned was soon seen to be too simplistic awarded the in 1904 for his work on (Archer, 1992). The deprivation experiments sug- digestion. Pavlov showed that if the sound of a bell gested by Lorenz, in which an individual is reared in accompanied the presentation of food to a dog, the isolation from other individuals and hence sources dog would learn to associate the sound with food. of learning, simply isolate an individual from its Eventually, the dog would salivate at the sound of the social environment rather than from temperature, bell even in the absence of food. Pavlov thereby pro- light and nutrition. Isolation experiments beg the duced the first demonstration of what later became question: From what has the animal been isolated? known as classical conditioning. By focusing on the Peking ducklings (Anas platyrhynchos), for example, observable reactions of animals without presuppos- are able to recognise the call of their species if it ing what went on in their minds, Pavlov stressed the is heard during embryonic development while the objectivity and rigour of these methods in contrast to chick is still in the shell (Gottlieb, 1971). Moreover, a psychology that dwelt upon putative inner experi- individuals create their own environment as a result ences. Pavlov’s work on conditioning became known of their actions. Aggressive or assertive people create to Western psychology around 1906 and, although a different environment from shy people, resulting his more ambitious claims for the establishment of a in a different set of feedback. It came to be real- new brain science went unheeded, his methodology ised that all behaviour must be the result of both proved highly influential. influences. The focus on the observable reactions of animals Important work by Thorpe (1961) on song devel- and humans under controlled conditions came to be opment in chaffinches demonstrated the mutual regarded as the hallmark of comparative psychology interdependence between heredity and the environ- and what later became known as behaviourism. It is ment. Thorpe demonstrated that whereas the ability easy to overestimate the influence of behaviourism of a chaffinch to sing was to some degree ‘innate’, on 20th-century psychology. Smith (1997) notes that the precise song pattern depended upon exposure to it served the polemical interests of cognitive psychol- the song of adults at critical times during the devel- ogists in the 1960s to represent psychology between opment of the young bird. The form the song took 1910 and 1960 as a behavioural monolith from also depended on the ability of the chaffinch to hear which they were seeking liberation. As a broad gen- its own song. Chaffinches would not, however, learn eralisation, however, a pattern was emerging. By the the songs of other birds, even if exposed from birth. middle of the 20th century, the European approach Furthermore, once song development occurred, a to animal behaviour and extrapolations to humans chaffinch would not learn other variants. Work such was dominated by ethology, while in the USA the as this showed that the interaction between innate experimental approach using laboratory animals was templates of behaviour and the environment is more pre-eminent. complex than hitherto thought. One figure who more than any other seemed Eventually, the classical ethologists had to accept to symbolise the behaviourist approach in its early that behaviour that they had often labelled as innate days was John Broadus Watson (1878–1958). In his could be modified by experience. It did not follow later years, Watson came to be reviled by ethologists from this of course that all behaviour was learnt and as the architect and archetype of an alien approach unconstrained by genetic factors, as some of the to the study of behaviour. By adopting a positivist behaviourists seemed to imply. The history of com- approach to knowledge, Watson claimed that psy- parative psychology is also one in which fundamen- chology would be retarded in its development unless tal assumptions had to be revised. it ditched its concern with unobservable entities

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

1 Evolution and Theories of Mind and Behaviour, Darwin and After 9

such as minds and feelings. Similarly, both animal Behaviourism sought philosophical credibility by and human psychology must abandon any refer- allying itself with a philosophy of science known as ence to consciousness. A psychology that deals with logical positivism and articulated by a group of phi- inner mental events is clinging, he claimed, to a form losophers known as the Vienna Circle. The logical of religion that has no place in a scientific age. For positivists argued that statements are only meaning- Watson, the brain was a sort of relay station that con- ful, and hence part of the purview of science, if they nected stimuli to responses. can be operationally defined. A statement about the Watson issued his manifesto in a series of lec- world then only becomes meaningful if it can be tures delivered in 1913 at Columbia University. verified. The aims of this approach were to outlaw Before the First World War, the reaction was luke- religious and metaphysical claims to knowledge. It warm: some welcomed his objective approach but was in this approach to epistemology that American warned against its excesses. Others feared that a sole behavioural psychology, with its emphasis on empir- concern with behavioural phenomena as opposed to ical, quantifiable and verifiable observations, found human consciousness would reduce psychology to a natural ally. a subset of biology. It was after the war that behav- The decline of behaviourism in the 1960s coin- iourism became more deeply embedded in American cided with the downfall of logical positivism as a scientific culture. The war had demonstrated the reliable philosophy of science. Philosophers such as value of objective tests applied in the classification Popper and historians such as Kuhn showed that the of military personnel. By 1930, behaviourism had verifiability criterion of meaning espoused by the become the dominant viewpoint in experimental Vienna Circle was untenable both in theory and as psychology. In stressing the importance of environ- a realistic description of the way in which science mental conditioning, Watson’s whole approach was actually worked. The irony of the linkage between profoundly anti-evolutionary and anti-hereditarian. behaviourism and positivism is neatly summed up by He denied that such qualities as talent, temperament Smith (1997, p. 669): ‘It appeared as if the behaviour- and mental constitution were inherited. Perhaps his ist enterprise had emptied psychology of its content most famous remark on the effect of environmental in order to pursue an image of science that was itself conditioning, and one of the most trenchant and a mirage.’ extreme statements of environmentalism in the lit- One movement in animal psychology related to erature, is his claim for the social conditioning of behaviourism was B. F. Skinner’s operant psychology. children: Skinner was professor of psychology at Harvard from 1958 to 1974 and was particularly influenced by the Give me a dozen healthy infants, well-formed, and in work of Watson and Pavlov. Skinner’s programme my own specified world to bring them up, and I will adopted a number of key principles. One was that guarantee to take any one at random and train him to he believed that science should be placed on a firm become any type of specialist I might select – doctor, foundation of the linkages between empirical obser- lawyer, artist, merchant-chief and yes, even beggar- vations rather than speculative theory. For Skinner, man and thief, regardless of his talents, penchants, and in this respect he resembles Watson, theoretical tendencies, abilities, vocations and race of ancestors. entities such as pleasure, pain, hunger and love were (Watson, 1930, p. 104) meaningless and should be expunged from labora- tory science. Another essential feature of Skinner’s In this respect behaviourism fitted in well with work was that he thought that all behaviour could American culture. It appeared to be a practical science be resolved and reduced to a basic principle of rein- that promised to deliver socially valuable answers to forcement. One typical schedule of reinforcement such things as how to raise children and turn them devised by Skinner was to reward pigeons in a box into effective citizens. It also arrived on the scene dur- with grain. By rewarding some forms of behaviour ing the First World War when anti-German sentiment and not others, he was able to make the rewarded made the notion of a distinctly American (as opposed behaviour more probable, an approach that became to German) science of psychology more appealing. known as operant conditioning.

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

10 Evolution and Human Behaviour

While early behaviourists in America such as became discrimination and language became verbal Watson were feverishly attempting to jettison excess behaviour. As Chomsky remarked, defining psychol- metaphysical baggage from psychology, in Europe, ogy in this way was like defining physics as the sci- Freud was weaving a psychology replete with rich ence of meter-readings. Chomsky’s review, and his and colourful complexes, emotions and subcon- own positive programme for linguistics stressing the scious forces. Skinner was both an admirer and critic creativity of language and its foundation on inher- of Freud. For Skinner, Freud’s great discovery was ent, deep-seated mental structures, sparked off a that human behaviour was subject to unconscious revolt against behaviourism that tumbled it into ter- forces. This accorded well with the view of behav- minal decline. This roughly coincided with increas- iourism that conscious reason was not in the driving ing reports from animal researchers that animals seat of human behaviour. Freud’s mistake was that trained according to operant conditioning methods he encumbered his theory with unnecessary mental would occasionally revert to behaviours that seemed machinery, such as the ego, the super ego, the id and to be instinctive. so on. For Skinner, such entities were not observable and hence were not justified in scientific enquiry. By 1960, a large number of psychologists in America had been trained in Skinner’s methods. 1.3 the rise of sociobiology and Their output was influential in some areas, such as evolutionary psychology the inculcation of desirable habits in the develop- ment of children, but few behaviourists were willing 1.3.1 From sociobiology to evolutionary to go as far as Skinner in suggesting that organisms ­psychology were empty boxes. Skinner faced his most difficult hurdle when, in his book Verbal (1957), In the 1970s and 80s, the contribution of ethol- he attempted to interpret language development in ogy to the natural sciences was recognised by the terms of operant conditioning. There were already award of Nobel prizes in 1973 to Konrad Lorenz, signs that many behaviourists were realising that Niko Tinbergen and for their work language threatened to be the ‘Waterloo’ of behav- on animal behaviour. Then in 1981, Roger Sperry, iourism. Skinner marched on, however, and argued David Hubel and were awarded the that there was nothing special about language, deny- prize for their work in . The classical ing any fundamental difference in verbal behaviour approach to ethology associated with Lorenz was between humans and the lower animals. Skinner had continued in Germany by Irenaus Eibl-Eibesfeldt now pushed behaviourism too far, and its weaknesses (1989). In the UK, the Netherlands and Scandina- were fatally exposed. via, where the influence of Tinbergen was more In 1959, a linguist called , then dominant, a more flexible approach to study of relatively obscure, reviewed Skinner’s Verbal Behavior animal behaviour was emerging. At Cambridge in and, in showing that behaviourism failed lamentably the 1950s, for example, under the leadership of when tackling language, also undermined some of its William Thorpe, ethologists became particularly basic pretexts. Chomsky argued that behaviourism interested in behavioural mechanisms and ontog- could hardly begin to account for language acquisi- eny, while at Oxford Tinbergen headed a group tion. He showed that Skinner’s attempts to apply the more concerned with behavioural functions and language of stimulus and response to verbal behav- evolution. In a sense, these two groups divided up iour lapsed into vagueness and finally hopeless con- Tinbergen’s four ‘whys’ (Durant, 1986). fusion. For Chomsky, behaviourism could not be Meanwhile, aided by some fresh ideas from theo- improved or modified: it was fundamentally flawed retical biology, a new discipline called sociobiology and had to go (Chomsky, 1959). In their efforts to was emerging that applied evolution to the social avoid unobservable mentalist concepts, the behav- behaviour of animals and humans. Sociobiology, iourists had indeed transformed psychological termi- like behavioural ecology, is concerned with the nology; so that memory became learning, perception functional aspects of behaviour in the sense raised

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

1 Evolution and Theories of Mind and Behaviour, Darwin and After 11

by Tinbergen. It drew its initial inspiration from of a more individualistic and gene-centred way of successful attempts by biologists to account for the viewing behaviour. troubling problem of altruistic behaviour. Of all the One example of the new approach that coun- problems faced by Darwin, he considered the emer- tered group selectionist thinking came in 1964 when gence of altruism and, more specifically, the exist- W. D. Hamilton published two ground-breaking ence of sterile castes among the insects as two of and decisive papers on inclusive fitness theory (see the most serious. Darwin provided his own answer Chapter 3). Then in 1966, G. C. Williams published in terms of community selection but also came tan- his influential and Natural Selection, in talisingly close to the modern perspective when he which he argued that the operation of natural selec- suggested that if the community were composed of tion must take place at the level of the individual near relatives, the survival value of altruism would rather than that of the group, and in a similar vein be enhanced. The British biologist J. B. S. Haldane exposed a number of what he thought were common came even closer when, in his book Causes of fallacies in the way in which evolutionary theory was Evolution (1932), he pointed out that altruism could being interpreted. In the 1960s and 70s, the British be expected to be selected for by natural selection if biologist John Maynard Smith pioneered the applica- it increased the chances of survival of descendants tion of the mathematical theory of games to situa- and near relations. tions in which the fitness that an animal gains from Sociobiologists such as Barash (1982) suggested its behaviour is related to the behaviour of others that the new discipline represented a new paradigm in competition with it. Then in the early 1970s, the in the approach to animal behaviour (Barash, 1982). American biologist Robert Trivers was instrumental Others such as Hinde (1982, p. 152) concluded that in introducing several new ideas concerning recipro- ‘sociobiology’ was an ‘unnecessary new term’ since cal altruism and parental investment (see Chapters behavioural ecology covered the same ground. 3 and 11). It is a sad reflection on the specialisation Behavioural ecology is an established and uncontro- of academic life and the disunified condition of the versial epithet for those who study the adaptive sig- social sciences that while this revolution was occur- nificance of the behaviour of animals. It would be a ring in the life sciences, psychology initially remained mistake, however, to treat ‘sociobiology’ and ‘behav- aloof from these ground-breaking developments. ioural ecology’ as interchangeable terms. Behavioural The book that encapsulated and synthesised ecologists tend to focus more on non-human ani- these new ideas more than any other was E. O. mals than humans and have a particular concern Wilson’s Sociobiology: The New Synthesis, published with resource issues, game theory and theories of in 1975. The book became a classic for its adher- optimality. Sociobiology itself deals with human and ents and a focus of anger for its critics. In this work, non-human animals, although it started out with a Wilson irritated a number of scientists by forecast- particular concern with inclusive fitness, and can be ing that the disciplines of ethology and comparative thought of as a hybrid between behavioural ecology, psychology would ultimately disappear by a canni- population biology and social ethology. The term balistic movement of neurophysiology from one side ‘human behavioural ecology’ comes close to that of and sociobiology and behavioural ecology from the ‘sociobiology’. other. Others were alarmed that Wilson (Figure 1.3) A book that served in some ways as a seed crystal extended biological theory into the field of human for the new approach – at least in the sense that it behaviour. Although only one chapter out of the galvanised its opponents – was Animal Dispersion in 27 in Wilson’s book was concerned with humans, a Relation to Social Behaviour, written by V. C. Wynne- fierce debate over the social and political implications Edwards and published in 1962. In this work, Wynne- of Wilson’s approach ensued. It was as if Wilson had Edwards advanced a position that was already present stormed the citadel that had been fortified from biol- in the literature but had aroused no real opposition, ogy by social scientists over the previous 40 years, namely that an individual would sacrifice its own with predictable repercussions. (genetic) self-interest for the good of the group. It One of these took place in February 1978 was attacks on this idea that catalysed the emergence when Wilson attended a meeting of the American

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

12 Evolution and Human Behaviour

surrounded Wilson’s early work. Partly to avoid asso- ciations with the vitriolic debates of the 1980s and partly to reflect a change in emphasis and ideas, the term sociobiology is now rarely used. The legacy of sociobiology now lives on, in modi- fied form, in the discipline called evolutionary psy- chology. Evolutionary psychologists focus on the adaptive mental mechanisms possessed by humans that were laid down in the distant past – the so-called ‘environment of evolutionary adaptedness’ (EEA). To be fair, sociobiology too had emphasised the impor- tance of adaptive mechanisms forged in the geologi- cal period known as the Pleistocene. There are those Figure 1.3 the American biologist Edward Wilson who insist that evolutionary psychology and socio- (born 1929). Wilson did pioneering work on the social insect biology are really the same thing. Robert Wright, in before publishing his massive and controversial work The Moral Animal: Evolutionary Psychology and Everyday Sociobiology in 1975. His subsequent contributions to Life (1994), for example, suggests that ‘sociobiology’ evolutionary thinking have been profound. was simply dropped as a name (for political reasons) Source: Photograph taken by Beth Maynor Young in although its concepts carried on under new labels: the Red Hills, Alabama, in 2010. By kind permission of Kathleen Horton (assistant to E. O. Wilson). Whatever happened to sociobiology? The answer is that it went underground, where it has been eat- ing away at the foundations of academic orthodoxy. Association for the Advancement of Science held in (Wright, 1994, p. 7) Washington DC. As he prepared to deliver his paper about ten people charged onto the stage accusing The rise of evolutionary psychology was facili- Wilson of genocide. One of them poured a jug of tated by the cognitive revolution in psychology. water over his head. One factor in promoting this revolution was perhaps As sociobiology developed its theoretical tools, the Second World War and the stimulus it gave to mainstream theoretical psychology, as epitomised research on information processing by machines by the journals Psychological Review and Psychological or human subjects in conjunction with machines. Bulletin, kept its distance and seemed reluctant to Cognitive psychology is based on the idea that men- engage with this fledgling discipline. Meanwhile, tal events could be conceived as the processing of some anthropologists were beginning to explore information within structures in the brain. As Tooby the application of sociobiological concepts to their and Cosmides (2005, pp. 14–16), two of the world’s field. In 1979 there appeared a ground-breaking work leading evolutionary psychologists, observe: edited by Chagnon and Irons: Evolutionary Biology and Human Social Behavior: An Anthropological Perspective, The brain’s evolved function is computational – to a book containing articles by Richard Alexander, use information to adaptively regulate the body and William Irons and Napoleon Chagnon. behaviour … the brain is not just like a computer. It is significant that, following Wilson’s book, a It is a computer – that is, a physical system that was number of new journals, such as and designed to process information. Sociobiology and Ethology and Sociobiology, appeared to cater for this growing area. The latter journal even- And just as a good computer has lots of applica- tually changed its name to Evolution and Human tions and sub-routines separate from each other (for Behavior, reflecting a new diversity of approach to example, word processing, playing music, handling the study of human behaviour. For many, the term images) so the brain, in this view, consists of a vari- ‘sociobiology’ is redolent of the painful debates that ety of modular-based capabilities. Parts of the brain

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

1 Evolution and Theories of Mind and Behaviour, Darwin and After 13

100 90 Nothing 80 70 Citation only 60 50 Discussed 40 centage of books

Per 30 20 10

0 1975–1979 1980–1984 1985–1989 1990–1994 1995–1999 2000–2004 n = 43 n = 31 n = 41 n = 40 n = 65 n = 42 Time period and sample size

Figure 1.4 coverage of EP in introductory evolutionary psychology (EP) was measured using a ­psychology texts 1975–2004. variety of criteria including coverage in the books, Source: Data adapted from Cornwell et al. (2005), accuracy of portrayal and the type of topics dis- Figure 1, p. 361. cussed. Figure 1.4, for example, shows how the atten- tion given to evolutionary psychology has increased ­useful for finding a fertile mate, for example, will not over the last 40 years. be called upon or be of much use in the task of iden- The authors also note that this increasing expo- tifying nutritious foods. sure was accompanied by a generally more accurate treatment, a more positive evaluation and fewer undefended criticisms. One troubling feature, how- 1.3.2 the influence of evolutionary psychology ever, was that many textbooks had narrowed the coverage of evolutionary psychology to mating An interesting question is whether or not evolution- strategies. ary psychology has had much impact on mainstream In view of the rather sordid history of some aspects psychology. After all, it was the prediction of Darwin of evolutionary theorising about humans it is neces- and Wilson that the evolutionary approach would sary, even at the risk of repetition elsewhere, to make eventually transform psychology. Barkow et al. some statements about how the Darwinian paradigm (1992) were equally sanguine when they stated that now stands on some of the issues raised in this chapter. evolutionary psychology had the ‘potential to draw Nearly all sociobiologists and evolutionary psycholo- together all of the disparate branches of psychology gists now assert the psychic unity of humankind; this into a single organised system of knowledge’ (p. 3). is done not out of political correctness – a poor founda- At the time of writing it is probably fair to say that tion for knowledge anyway – but simply because the the evolutionary approach has not yet unified psy- biological evidence points in that direction. Where chology in the way its protagonists hoped it would, Darwinians profoundly disagree with the ‘nurturists’ and mainstream psychology remains in a state of, to is the view of the latter that our evolutionary past put it charitably, ‘conceptual pluralism’. has no bearing on our present condition; that human In an effort to examine what influence evolution- behaviour and the human mind and are moulded and ary psychology has exerted, Cornwell et al. (2005) conditioned solely or largely by culture; and, crucially, examined 262 introductory psychology textbooks culture bears no relation to our genetic ancestry and spanning the period 1975–2004. The influence of hence can only be explained in terms of more culture.

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

14 Evolution and Human Behaviour

In contradistinction to this, Darwinism asserts during development in functional ways that further the existence of human universals upon which the enhance fitness. This is considered in more detail in essential unity of humankind is predicated. Some Chapters 7 and 8. cultures may amplify some of these universals and In retrospect, perhaps a better way to understand suppress others, and culture itself may in some as the historical status of sociobiology is in phylo- yet unclear way reflect the universals lurking in the genetic terms. In this light we might suppose that human gene pool, but the crucial point is that these sociobiology is the ancestor of such descendants as universals represent phylogenetic adaptations: they human behavioural ecology, evolutionary psychol- have adaptive significance. This is not to suggest of ogy and gene–culture evolution theory. To continue course that there are ‘genes for’ specific social acts; the metaphor these descendants have drifted apart genes describe proteins rather than behaviour. It and now tend to recruit different types of scientists, will be genes in concert with other genes and envi- emphasise different aspects of the evolutionary pro- ronmental influences (meaning both the cellular ject and vary in their toolkits of models, theories and extracellular environments) that are seen to and methodologies. Yet beneath this diversity they shape the neural hardware of the brain that forms belong to the same genus and share the same over- the ultimate basis of human universals. Moreover, arching aims. These different approaches, all mem- there is increasing evidence that in addition to dis- bers of Darwinian paradigm, are considered in the tinct human universals one characteristic of humans next chapter. is their behavioural plasticity: the ability to adapt

Summary

[[Darwin and some of his immediate followers sought an explanation of animal and human minds based on the principle that the mental and physical life of animals belong to the same sphere of explanation and that both have been subject to the force of natural selection. [[In the 20th century, two distinct approaches to animal behaviour emerged: ethology and comparative psychology. The ethological tradition in Europe was based around the work of such pioneers as Heinroth, Lorenz and Tinbergen, entailing the study of a variety of animal species in their natural habitat using a broad evolutionary framework. Comparative psychology took root particularly in America. Watson and Skinner were extreme representatives of this tradi- tion. With the passage of time, comparative psychology became increasingly concerned with the behaviour of a few species in laboratory conditions, to the neglect of an evolutionary perspective. [[The theory of human instincts begun by Darwin was continued in America by James and in Europe by Heinroth, Lorenz and other ethologists. The experi- mental problem of demonstrating the action and existence of human instincts, as well as the reactionary associations of biological theories of human nature, led most social scientists and anthropologists in the middle years of the 20th century to reject biological explanations of human behaviour and assert the primacy of culture. [[Seeking explanations for human behaviour in terms of adaptations lies at the heart of Darwinian psychology and provides ‘ultimate’ style explanations for current behaviour. Such explanations are responses to two of the four ‘whys’ of

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

1 Evolution and Theories of Mind and Behaviour, Darwin and After 15

animal behaviour set out by Tinbergen: how the behaviour has evolved (‘evolu- tion’) and the survival value of the behaviour (‘function’). [[In the 1960s and ‘70s, a number of fundamental papers and books set in ­motion the sociobiological approach to animal and human behaviour. Sociobiology is predicated on the view that animals will behave so as to maximise the spread of their genes. Behaviour is therefore examined largely with functional (in the sense of Tinbergen) questions in mind. When applied solely to humans, the approach is also sometimes called evolutionary psychology (EP), some regard- ing this movement as a new paradigm. This new movement seeks to revive the Darwinian project of demonstrating the evolutionary basis of human behaviour and of many facets of human culture. [[The cognitive revolution in psychology precipitated the demise of behaviour- ism and allowed evolutionary psychology to flourish. [[Evolutionary psychology is slowly making headway into mainstream psych­ ology and increasingly features in introductory textbooks. Its promise to ­transform psychology and provide it with a much-needed unifying base in an ongoing task.

Key Words

• Behaviourism • Function • Proximate cause • Environment of evolutionary • Gene pool • Selection adaptedness (EEA) • Ontogeny • Species • Environmentalism • Operant conditioning • Ultimate causation • Fitness • Paradigm • Fixed action pattern • Positivism

Further reading

Degler, C. N. (1991). In Search of Human Nature: The Decline and Revival of Darwinism in American Social Thought. Oxford, Oxford University Press. True to its title, this book examines the period 1900–88. A penetrating sociological analysis of the fate of Darwinian ideas in America.

Gangestad, S. W. and J. A. Simpson (2007). The Evolution of Mind. London, UK, The Guildford Press. Excellent set of articles on the whole field of evolution and human behaviour. Several articles address fundamental theoretical and methodological issues.

Plotkin, H. (2004). Evolutionary Thought in Psychology. A Brief History. Oxford, Blackwell. An excellent, readable and balanced discussion of evolutionary thinking in psychology lead- ing up to EP.

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

16 Evolution and Human Behaviour

Richards, R. J. (1987). Darwin and the Emergence of Evolutionary Theories of Mind and Behaviour. Chicago, University of Chicago Press. A detailed and thorough work. Covers the ideas of Darwin, Spencer, Romanes, Morgan and James. Lays particular emphasis on the evolutionary origins of morality. Contains the author’s contemporary defence of using evolution as a basis for ethics.

Segerstrale, U. (2000). Defenders of the Truth: The Battle for Science in the Sociobiology Debate and Beyond. Oxford, Oxford University Press. A highly detailed account of the characters and controversies involved in the rise of sociobiology.

Thorpe, W. (1979). The Origins and Rise of Ethology. New York, Praeger. An inside account of ethology from someone who helped to shape the discipline. Plenty of anecdotal information.

Workman, L. (2013). Charles Darwin: The Shaping of Evolutionary Thinking. Basingstoke, UK, Palgrave Macmillan. Clear and thoughtful book about the influence of Darwin on thinking about behaviour.

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005 Index

A Behavioural immune system 429, 430 Acclimation 112 Behaviourism 8–10 Acclimatisation 112 Bergmann’s rule 125–126 Adaptive landscape 19, 21, 343, 353, 435 Bifidobacteria 344, 436 Adaptive thinking 20, 171 Bipedalism 76, 87, 256, 343, 355, 356 significance 21 Bipolar disorder 123, 387–390 Adaptations 17, 20 Birth interval 88, 100, 142, 144, 156, 157, 159 Adelson chequered square 167 Body Mass Index (BMI) 436 Adolescence 144 and attractiveness 277, 279, 281–283 Ageing 157 in hunter gatherers 381–382 Allele 39, 435 Bounded rationality 171 Allen’s rule 125–126 Bowlby, John 151 Allometry 95 Brain Altricial 72 and climate variability 102–103 Altruism 42, 205, 206 energetic demands 98–99 and costly signalling 226 lateralisation 88 Amino acids 75, 76, 121, 362, 435 size 94 Amygdala 198 Breast milk 344–345 Amylase 23, 383, 409–410 Broca, Pierre 105 Amylose 409 Broca’s area 105 Androgens (see also testosterone) 140, 145, 435 Androphilia 312 C Animism 177, 178, 179 Cancer Anisogamy 52 and cell division 386 Antagonistic pleiotropy 156, 157, 342, 343, and evolution 384 361–363, 388, 391, 435 and mutation rate 385 Anthropocene 85 Categorical imperative 421, 432, 436 Antibiotic resistance 342, 344, 349 Central nervous system 191 Appendix 358–360 Cerebral cortex 88, 191, 436 151 Chaffinch 8 and reproduction 152–153 Chimpanzees 75, 98, 144, 195 Australopithecus and sexual selection 261 afarensis 76, 77 Chomsky, Noam 10 africanus 76, 77 Chromosomes 81, 307, 436 boisei 78 and epigenetics 124 robustus 78 and homosexuality 361 Autonomic nervous system 198, 436 sex (X and Y) 80, 118, 120, 123 Asymmetry 436 Cinderella syndrome 239 fluctuating 293–294, 438 Cladistics 72 Autism 388, 389, 390, 436 Coefficient of relatedness 44 and parental age 391 Cognition Averageness 294 sex differences 183–184 Axelrod, R. 217, 218, 219 Cognitive adaptations 166 B biases 173 Base-rate fallacy 169–170, 174–175 illusions 168–170 Baysean reasoning 169–170 Comparative psychology 8–10 484

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

Index 485

Conditioning 8, 9, 10, 121, 366, 401 Darwin’s theory of 191 Conformist bias 23, 30, 173, 404, 437 functionality of 194, 200 Conjunction fallacy 170, 173–174 homology of 194 Consequentialism (see also utilitarianism) 423 James-Lange’s theory of 191 Consilience 411, 412, 437 paradox of 201 Cooperation 207 universality of 195 Cosmetic surgery 269 Encephalisation quotient 96 Cosmides, L. 24 Endocrine system 139 Cousin marriage (see also incest) 325–328, 330 Energetics of growth and gestation hypothesis Crime 242 (EGG) 357–358 age and crime curve 242 Environment of Evolutionary Adaptedness (EEA) 12, Culture 399 22, 26, 171, 413, 427, 438 models of gene culture interactions 400 Environmentalism 9 Culturgen (see also “memes”) 403, 437 Eocene 84 Cystic fibrosis 39, 362,363, 437 Epigenetics 113, 117–118, 121–122 transgenerational effects 113, 119, 120, 124 D Error management theory 175–182 Darwin, Charles 3 and biases in perception 177 and marriage 327–328 and protective effects 177 and vestigial traits 358–359 and type I and type II errors 176 and The Origin of Species 4 328, 438 Darwin, George 328 Eusocial (insects) 45 Darwin, Leonard 328 Evolutionary psychology 13, 21, 22, 23 Darwinian Ethology 5–8 anthropology 23, 27 Evolutionary epistemology 165, 166 grandparenting 208–210 Evolutionarily stable strategy (ESS) 218 medicine 341 Exogamy 81, 300, 331, 438 Darwinism 35 Expensive tissue hypothesis 100 Dawkins, Richard 43, 166, 192, 205, 206, 341, 360, Ewald, Paul 342 401, 410, 415, 439 Extended phenotype 205, 206, 400, 410, 412, 438 Demographic transition 29, 159–160, 437 Eye Depression 200, 371, 388 cephalopod 353–354 bipolar 436 vertebrate 353–354 unipolar 388, 390, 391, 445 Developmental plasticity 113, 114, 115, 116 F and body proportions 128 Faces and developmental origins of health and and averageness 280, 294 ­disease 351 and expression of emotions 196 and epigenetics 121 and neoteny 302–305 and individual differences 132, 136 and MHC complex 306–308 and Life History Theory 139, 140, 148 and trade-off theory 297 Developmental origins of health and disease paradigm attractiveness and conception risk 298 (DOHaD) 344, 351–352 dimorphism of 301 Diabetes of children 208, 233 type II 115 of chimpanzees 195 Disability adjusted life years (DALYs) 371, 372 of teddy bears 303 DNA 37 recognition of 183 epigenetic modification of 38 Facial expressions 197 methylation 122, 123 Fast and frugal heuristics 172 mitochondrial 80, 81, 82, 83 Fertile crescent 374 mutations of 39 Fisher, R. A. 53 29, 403, 437 Fat 377 Dutch Hunger Winter 116–117 saturated 377, 378, 381, 444 unsaturated 377, 378 E Fisher, R. A. 42, 53, 54, 64, 65, 388 Ekman, Paul 193, 195–197 Fitness 20, 29 Emotions 190 inclusive 42, 44, 208 as adaptations 192 Fixed action pattern 6, 302, 438

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

486 Index

Four whys 7,10 floresiensis 74, 80 Frequency dependent selection 133, 306 genus 71 Freud, Sigmund 10 habilis 76, 77, 78, 98 heidelbergensis 80 G naledi 77 Galton, Francis neanderthalensis 77, 80 and eugenics 327 rudolfensis 79 and faces 294 sapiens 74, 98 Game theory 216, 220 Homogamy 309–310 and moral passions 223 Homology 183, 194 Gametes 47, 52, 53, 61, 62, 259, 283, 435, 439 Homosexuality Gene-culture coevolutionary theory 23, 29–30 and fraternal birth order 318 Genetic drift 19 and sexually antagonistic selection 315–316 Genome lag theories 26, 28, 192, 342, 371, 380, 383 and the X chromosome 314, 316 Genomic imprinting (see also imprinting) 101, 118, attitudes to 320 439 concordance rates 314 Genotype 36 in twins 314 Gigerenzer, G. 170–174, 404 genetic basis of 313–314 Glucose-6-phosphate dehydrogenase Honest signals 64 deficiency 361–362 Hume, David 166, 190, 336, 418, 419, 420, 433, 442 Glycaemic index 342, 358, 376, 377, 439 Hunter gatherers Glycaemic load 376, 377, 381 and calorie intake 373 Godwin, William 420, 421 and diet 377, 379–381 Gorillas 75, 98, 144 and Hadza 279 and sexual selection 261 and jaw sizes 350 Grandparental solicitude 210 and life expectancy 382, 383 Green beard effect 46, 207, 439 and mating systems 255, 256 Greylag goose 6 and menstruation 236 11, 42, 43, 439 Huntington’s disease 343, 362–363, 440 Gynephilia 312 Huxley, T. H. 94 Hygiene hypothesis 351 H Hyperglycaemia 376, 377, 440 Habituation 112 Hyperinsulinemia 376, 377, 440 Hadza 150, 187, 279, 280, 410 Hypertension 115, 116, 277, 377, 378, 380, 440 Haig, D. 233, 234 Hair loss (human) 87, 91, 92 I Haldane, J.B.S. 11, 42 Imprinting 117–118 Hamilton, William 42–43 filial 308 rule 43–45, 205, sexual 309 Handedness 133 Inbreeding Hardin, G. 221 coefficient of 325, 329 Heinroth, Oscar 5, 308 in Darwin’s family 327–328 Heritability 39–42, 131 in royal families 327 Heterozygotic advantage 361, 389 negative consequences of 326 and homosexuality 316 Incest Heuristics 171 and Freud 324 High heels 284 and morality 335 Hinde, R. 151, 303, 304 and Westermarck effect 324–335 Hippocampus minor 94 aversion 325 Hobbes, Thomas 336, 420 aversion to third party 214 Holocene 27 laws relating to 333–334 Homeostasis 112 taboo 323 Homicide 235 Individual differences 132 Hominids 72 54, 56, 57, 232, 233, 236–239, 423, 440 Hominins 72 Insulin 113, 114, 115 Homo and foetus 234 erectus 76, 77–78, 79, 98 resistance 115, 116, 352, 376–377, 381 ergaster 77 Isogamy 52

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

Index 487

J Memes 23, 47, 401, 441 James, William 3, 166, 191, 438 and religious belief 415 Jealousy 247 spread of 402 Just So Stories 17–18 Menarche 144, 147–148 and attachment 150–151 K Menopause 154 K-selection 140 Menstruation 147–148 Kahnemann, D. 168 Meiosis 38, 39, 119, 441, 442, 444 Kant, Immanuel 166, 336, 423, 424, 426, 432, 437 Mental disorders 387, 391 Kin Mental rotation test 184–186 recognition 46, 212, 213 Milankovitch cycle 406 selection 42 Miocene 73 Kinship estimation 213 Mitichondria 82 Kipling, Rudyard 17, 18 Mitochondrial eve 82–83 Mitosis 442 L Modular view of mind 25–27 Lack, David 6 Modularity 26, 27, 167, 182, 183, 442 Lactose Modules 24 In breast milk 345 plasticity of 182–183 intolerance 342 Monogamy 51, 256 tolerance 23, 39, 112, 125, 383, 406–409 Monozygotic twins 39, 41, 123, 313, 314, 387, 446 Lamarck, Jean Baptiste 36 Moral foundations theory 425–428 36, 119 Morning sickness 342, 343, 366–368 Language 103 Multiregional model 78 Lap dancing 290 Mutualism 206, 214, 220 Lice (human) 92–93 Mutations 39, 442 Life expectancy 133, 134, 150, 152, 155, 158, and disease 362, 388, 390 382–383 and lactose tolerance 408 Life History Theory 138–145 and parental age 390–392 and demographic transition 158–159 and SNPs 38–39 Linnaeus, Carl 71 in Mitochondria 83 Linnean Society 4 load 132 Locke, John 165, 166 M168 80 Lorenz, Konrad 5, 10, 151, 284, 285, 302, 308 rate of 385, 389 Lyell, Charles 4 Mutation selection balance 390

M N Machiavellian intelligence 102 Natural selection 3, 4, 21, 30, 35–40, 400–403, Malaria 347, 361, 362 405, 412 Marriage 246 36, 111, 354 age differences 154 Naturalistic fallacy 418, 442 and divorce 256 Neolithic revolution 84, 99, 255, 256, 344, 346, 349, as reproductive contract 246 371, 373, 375, 377, 382, 407 first cousin 325,326 Neoteny 302 gay 310 and infantile faces 302, 305 major and minor 329 in dog faces 302 of Charles Darwin 327 in teddy bears Major Histocompatibility Complex (MHC) 46, 213, Nesse, R. M. 178, 341, 342 288, 306–11, 332 Mate choice O and advertisements 274–275 Obstetrical dilemma hypothesis 356, 358 and BMI 281–282 Obstetrics 356 and body shape preferences 276–283 Oedipus 229, 323 age difference preferences 271–274 Oedipus Rex 323 criteria 275 Oestrus 231, 236, 257, 259 Cross cultural comparisons 270 signals of 264, 290, 300 Maternal-foetal conflict 230, 233–234 Oligosaccharides 344, 345, 442 Maynard-Smith, John 11, 42 Oogenesis 119, 442

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

488 Index

Operant conditioning 9, 10, 366, 442 Pliocene 73, 372 Optimality 11, 23, 28, 30, 138, 161, 168, 283, 442 Polyandry 51, 52, 255 Optimism bias 180 Polygamy 51, 52 Orang-utans 75, 98, 144 Polygynandry 51, 52 and sexual selection 261 Polygyny 51, 52, 255 Orbitofrontal cortex 198 Popper, Karl 9, 166, 405 Origin of Species, On the 3, 4, 111, 411 Positivism 9 Os penis 88 Posture 89, 355 Out of Africa Hypothesis 78 and high heels 284 Out of Eden hypothesis 342 Potassium in diet 378 Ovarian cycle 264, 286, 288, 442 Precocial 72 and facial preferences 300 Pregnancy sickness (see morning sickness) and intercourse 287 Prestige bias 29, 173, 404, 405, 443 and probability of conception 61, 298 Prisoners’ dilemma 217–218 Ovulation 286, 442 Probiotic bacteria 344 and Extra pair copulation theory 288 Proximate causation 6 and health 277 Puberty 144 concealed 148, 244, 264–266, 286 and body stature 149 signs of 289 Pygmies 149–150 suppression by lactation 140 Oyster catcher 6, 284 R Rawls, John 336, 426, 432 P r-selection 140 Palaeolithic 215 and diet 371, 375, 376, 378, 383, 384 Reciprocity 205 and language 103 indirect 222 and stature 358 Religious belief 412 Panglossianism 18 and attitudes to homosexuality 320 Paradigm 3 and gene-culture coevolution 415 Parasites 46, 65, 91, 92, 144, 149, 205, 217, 280, and hypersensitive agency detection 294, 295, 296, 306, 348, 366, 401, 403 device 413 Parasitism 205 and incest 333–334 Parent-offspring conflict 230–231 and memes 403 generalised model 232 cognitivist accounts of 412–414 Parental certainty 208, 210 Darwinian accounts of 414 Parental investment 60 Reproductive value 156, 168, 180, 232, 236, 275 Pathogens 443 and age 237 and behavioural immune system 429–430 and infanticide 238 and body hair 92 residual 272, 273 and menstruation 148 Reputation 222, 224 and morning sickness 366–368 Reverse engineering 20 and Neolithic revolution 346 Ridley, M. 222 and vectors 347–348 Robin 6 Patrilocal (residence) 54, 210 and virulence 346 S Pavlov, Petrovich 8 Sabine women 301 Phenotype 36 Satisficing solutions 172 Phenotypic gambit 27–28 Schizophrenia 123, 371, 387, 388–391, 444 Phenotypic plasticity 19 and parental age 392–393 Phylogenetic inertia 19 Senescence 157 Phylogeny Sexual crypsis 264, 265, 298, 444 of primates 75, 266 Sexual dimorphism 62–63, 85 and appendix 359 and body size 258 Pinker, S. 103, 104, 105, 194, 200, 412, 426, 432, 433 Sexual selection 53, 58–59, 258 Plato 165 and testis size 259 Pleistocene 12, 22, 23, 25, 26 and body size dimorphism 259 and climate 406 inter 58 and diet 375–379 intra 58

Copyrighted material – 9781137348005 Copyrighted material – 9781137348005

Index 489

Sex ratio 53 as a negative handicap 295–296 in Asia 54 levels in fathers 140 operational 60–62 prenatal exposure 133, 317 Shim-pua (marriage) 329, 330 Theory of Mind 24, 25, 250, 436 Sibling rivalry 234 Thrifty genotype 114 Sickle cell anaemia 39, 343, 361, 362, 363 Thrifty phenotype 115 Single nucleotide polymorphisms (SNPs) 39 Tinbergen, Nikolaas 5–7 Skin Tit for tat strategy 218–219 colour 128–131 Tooby, J. 24 damage by UV 128–130 Tragedy of the Commons 221 reflectance 130 Trans fatty acids 377, 445 Skinner, B. F. 9–10, 181 Triune brain 424 Smoke detector principle 178, 181, 343, 368, 445 and ethics 424 Social brain hypothesis 102 Trivers, R. 60, 218 Sociobiology 10–12 Trolley (runaway) 421–425 Sociobiology, The New Synthesis 4, 11, 425 Tversky, A. 168, 170, 173 Socrates 165 Sodium in diet 378 U Speciation 74 Ultimate causation 6, 7, 241, 341, 365, 384, 413, 445 Spencer, Herbert 166, 445 Utilitarianism 419, 423, 425, 446 Sperm and MHC complex 307 V and mitochondrial DNA 83, 391 Vampire bats 215 banks 29 Vestigial structures 358–359, 413, 414, 446 competition 28, 58, 63–64, 245 Virulence 346–348, 351, 446 dimensions 52 Vitamin C 376 in ejaculate 52 Vitamin D 17, 129, 130, 131, 358, 379, 407 lifespan 286 midpiece size 263 W mutations in 388 Waist-to-hip ratio (WHR) 277 swimming speed 262 and BMI 281 Spite 206 and mate choice 278 Starch (in diet) 23, 112, 383, 409–410 in Hadza people 279–280 Strategic interference theory 244–245, 250 Wallace, Alfred Russel 4 Supernormal stimuli 284 Walking gait 284 Superstition 181 Westermarck, E. 324 among pigeons 181 Westermarck effect 309, 323–336, 446 Symmetry 445 Watson, John Broadus 8–9 and facial attractiveness 293–295 Weismann, August 37 and mate quality 63, 65 Wernicke, Karl 105 and odour 289 Wernicke’s area 105 Whewell, W. 411 T Williams, G. C. 18 Taxon 71 Wilson, E. O. 11–13, 29, 43, 206, 411, 412, 425 Taxonomy 72 Wolf, A. 329–331 Teleology 36, 112, 413, 445 Wynne-Edwards, V.C. 42 Teleonomy 111 Testis size 260 Y Testosterone Yanomamo 134, 380, 381 and handedness 134 Y –chromosome Adam 81 and immunocompetence 146 and life history allocations 145–146, 147, 365 Z and masculinity 300 Zoonosis 345, 446 and violence 243 Zoonotic diseases 344, 345, 346 and Waist-to-hip ratios 279 Zulus 281, 282

Copyrighted material – 9781137348005