A Window to the Structure of the Mind

Forum TRENDS in Cognitive Sciences Vol.6 No.12 December 2002 537

Book Review

patterns: the various authors cases of neuropathology (Decety, A window to the demonstrate that adults and children Kinsbourne, Goldenberg and structure of the mind (Bekkering, Gattis and colleagues, Prinz, Hermsdörfer). Vogt), infants (Meltzoff), and non-human The existence of common primates (Byrne, Whiten) represent representations for self-produced and The Imitative Mind: Development, action in terms of its goal structure. observed actions leads to the speculation, Evolution and Brain Bases As Tversky and colleagues elucidate, expressed widely in the book (and edited by Andrew N. Meltzoff and goal-directed action is richly structured. elsewhere), that these representations Wolfgang Prinz, Some aspects of this structure are could contribute to mind-reading. Cambridge University Press, 2002. represented at different points in Developmentalists find this possibility £47.50 (353 pages) ISBN 0 521 80685 2 ontogeny, in different species, or in particularly intriguing because it different situations. The book provides provides a wedge into a classic Imitation has long initial insights into these more specific developmental problem – how children intrigued students aspects of action representation, learn to ‘read’ what others are thinking. of human nature, including the ability to interpret the The suggestion in this book is that because it is both same motor pattern flexibly based on imitation provides a window to the mind pervasive in an analysis of the actor’s goals (Decety, for children as well as for cognitive human life and a Gattis and colleagues, Prinz), sensitivity scientists. A number of authors suggest channel connecting to the hierarchical and sequential that imitation itself plays a causal role the individual structure of action (Byrne, Whiten), in the development of mind-reading mind to the social and the ability to anticipate the outcome (Heimann, Meltzoff), whereas others and cultural of an incomplete action (Jellema and suggest that mind-reading and imitation context in which it colleagues, Meltzoff). are separate products of the same set of lives. There is a Imitation rests on the ability to relate representations (Bekkering, Jellema and recent resurgence of interest in imitation one’s own actions to the actions of others. colleagues, Prinz, Rizzolatti). among investigators of cognition and Throughout the book there is converging In order for a mirroring system to perception, cognitive neuroscience, evidence for an important insight into contribute meaningfully to action human development and comparative this process – that observed and knowledge, much less to mind-reading, cognition [1]. A number of groundbreaking self-produced behaviors are united by it must be informed by systems for discoveries across these domains have common neurocognitive representations. analyzing behavior into meaningful led to the converging conclusion that Elegant behavioral research has shown units. Throughout the volume there is imitation and the processes by which it that producing a particular action and attention to this issue, including occurs offer a unique window to the mind. perceiving that action draw on some of investigations of neural systems that Building on this synergy, Meltzoff and the same representational resources respond to behavior at different levels of Prinz have assembled a volume that both (Bekkering, Prinz, Vogt). Moreover, analysis (Decety, Jellema and colleagues, illustrates the growing breadth of interest recent findings have revealed neural Rizzolatti and colleagues), as well as in imitation and distills the core questions substrates (so-called ‘mirror neurons’) the cognitive, comparative and that surface across disciplines. These that respond to both observed actions and developmental work described above. questions concern the level at which self-produced actions (Decety, Rizzolatti In addition, there is broad consideration action is represented and the system that and colleagues). These findings yield of the importance of distinguishing relates self-produced actions to the important insights into perception–action information about the self from observed actions of others. relations, the production of voluntary information about others, and the A critical insight emerging throughout behavior, and neural architecture. development and function of self- the book is that behavior can be imitated Crucially, they also indicate that awareness (Asendorpf, Goldenberg and at various levels, from specific motor imitation can result directly from Hermsdörfer Kinsbourne, Meltzoff, patterns to the more abstract goals that the activation of these common Nadel, Reed, Rochat). These converging guide action. This insight informs representations, requiring no translation lines of work might one day yield an debates about whether, when and why to account for the match between actions account of the origins of theory of mind reproducing the specific motor details of perceived and actions performed. This in human children. They might also help an action are crucial (see Refs [2,3], as activation would be maladaptive if it were to explain why, despite cross-species well as the chapters by Byrne, Gattis expressed for all actions. Several authors commonalities in action representation, and colleagues, Meltzoff, and Whiten). propose mechanisms for the modulation only humans create a theory of mind. This insight also shows that imitation of imitative behavior (Bekkering, Decety, can be used to investigate action Kinsbourne, Rizzolatti and colleagues), Camille Wilson representations. Many chapters of the and several consider instances in which Dept of Psychology, University of Chicago, book illustrate this method, converging this modulation fails to occur – in infancy 5848 South University Avenue, Chicago, on the conclusion that actions are (Decety, Kinsbourne, Heimann), in IL 60637, USA. represented beyond the level of motor autism (Nadel, Whiten), and in certain e-mail: [email protected]

Amanda L. Woodward magnitude of reinforcement. The second Anthony Dickinson Dept of Psychology, University of Chicago, issue is the timescale invariance of Dept of Experimental Psychology, 5848 South University Avenue, Chicago, acquisition which the authors claim is University of Cambridge, Downing Street, IL 60637, USA. both the single most important discovery Cambridge, UK CB2 3EB. e-mail: [email protected] about conditioning, and problematic for e-mail: [email protected]

References associative theory. This invariance refers 1 Heyes, C. (2001) Causes and consequences of to the fact that acquisition is determined imitation. Trends Cogn. Sci. 5, 253–361 by the ratio of the interval between Back to nature 2 Tomasello, M. et al. (1993) Cultural learning. reinforced CSs to the duration of the CS, Behav. Brain Sci. 16, 495–552 whatever the absolute lengths of these 3 Gergely, G. et al. (2002) Developmental psychology: rational imitation in preverbal intervals and the probability of The Blank Slate: The Modern Denial of infants. Nature, 415, 755 reinforcement. The final issue concerns Human Nature the failure of associative theory to provide by Steven Pinker, an account of the subtle timing of Viking 2002. £25.00/$27.95 (509 pages) conditioned behaviour. ISBN 0 670 03151 8 Opposing In response to these challenges, associationism Gallistel and Gibbon offer a cognitive When Steven theory in which they assume that, Pinker’s Language during training, an animal encodes and Instinct came The Symbolic Foundations of remembers both the times at which out in 1994, a Conditioned Behavior reinforcers occur in the CS (based on philosopher friend by C. Randy Gallistel and John Gibbon, SET) and the rates of their occurrence of mine described Lawrence Erlbaum, 2002. (based on RET). Then, when presented it as a wonderful £49.95 (196 pages) ISBN 0 8058 2934 2 with a test CS, the animal retrieves book with an awful memories of these intervals and rates ending. Being This is an important, provocative and before choosing whether to respond and, greatly influenced polemical book. The target of the polemic if so, when to respond, on the basis of by Noam Chomsky, is associationism, the most venerable decision rules. This account is applied she was tradition in learning stretching back to not only to response acquisition and sympathetic to Pinker’s arguments that the British empiricist philosophers, Locke timing but also to complex temporal language is an innate module – an and Hume. Not only do Randy Gallistel inferences revealed in studies of instinct – and persuaded as well that and the late, and greatly missed, secondary conditioning, and to the language has evolved through natural John Gibbon attack associationism in its operant choice behaviour. selection. But she was troubled by his citadel – namely animal conditioning – Whether or not this cognitive theory suggestion in the final chapter that the but they also seek to usurp its authority presents a serious challenge to the same approach should be extended to with a synthesis of two cognitive theories. hegemony of associationism is far from psychology more generally. Pinker’s next The first is Scalar Expectancy Theory certain. Gallistel and Gibbon clearly seek book, How the Mind Works, did just that, (SET), developed by Gibbon over many to influence the neuroscience community applying a biological perspective to years to explain the temporal control by persuading us of the illusory nature everything from depth perception to of behaviour, and the second is Rate of what they call the ‘neurobiological maternal love to aesthetic appreciation. Estimation Theory (RET) that was transparency’ of associationism. But be She hated this book, seeing the whole elaborated by Gallistel over 10 years ago warned – this is not an introductory book enterprise of evolutionary psychology to account for the acquisition of and a critical appreciation of its central as repugnant: morally suspect and conditioning. This synthesis was theses requires a firm grounding in both politically reactionary. presented in a paper published in conditioning and associative learning The Blank Slate is written for her. Psychological Review in 2000, and the theory. Moreover, I suspect that Pinker does a lot of things in this present volume is an elaboration of associative theorists will be mildly extraordinary work, but his main goal is that paper. irritated by the numerous, dismissive to show that the notion of an evolved Gallistel and Gibbon challenge over-generalizations that ignore many of human nature does not have the negative associationism on three main issues. the subtleties of their theories. My own connotations that many people think it The first concerns the representational judgment is that RET is too baroque an does. There is no conflict between a poverty of the concept of associative account to have a sustained influence materialist and biological perspective on strength. According to associative theory, in the field. Even so, it must be the mind and the religious, political and the predictive relationship between a acknowledged that this book is a unique moral values that people hold most dear. conditioned stimulus (CS) and reinforcer contribution to conditioning and Pinker starts by identifying three is encoded by the strength of an learning. To maintain a healthy and doctrines: the blank slate (mental association, a form of encoding that generative state, every theoretical structure comes from the environment, conflates many different features of the programme needs an official opposition mostly from culture), the noble savage relationship, most notably the amount and, at long last, associationism has (humans are essentially good) and the of training with the probability and found a worthy one. ghost in the machine (mental life is the