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Chaos and Intoxication: Complexity and Adaptation in the Structure of Human Nature

Alan Dean
London: Routledge
Cloth: ISBN 0-415-14614-3; Paperback: ISBN 0-415-14615-1

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Reviewed by
Neil Hunt
Invicta Community Care NHS Trust, George Villa, Hermitage Lane, Maidstone, Kent ME16 9PH, UK.

Cover of the book In this book, Alan Dean addresses the ambitious project of producing "... a general theory of human nature which accounts for all the observed data ..." and that is able to answer the question "... what is it that leads to predictability (similarities) and uncertainty (dissimilarities) with regard to behavioural, social and cultural outcomes?" He selects the example of intoxication to present his argument, on the basis that the "... interesting dissimilarities in practice and social responses surrounding drug and alcohol use seem to provide an excellent means to explore questions relating to personal, social and cultural diversity and universality ..."

Such a project has wide relevance and is of potential interest to social scientists, specialists within the field of drug use (or misuse) and, insofar as this is a book about an important aspect of what it is to be human, to any general reader interested in asking fundamental questions about themselves and others. More particularly, it may be of interest to researchers using simulation in the social sciences because of the way Dean structures his argument. He gives an account that constantly emphasises the links between the micro level of genetics and the macro level of sociality. Such an analysis will have intuitive appeal to those using simulation for whom any account of a complex phenomenon, such as 'human nature', that fails to integrate multiple levels of description will be seen as partial. Dean's attempt to draw out these connections is both thought provoking and thorough. He assesses his own work as a "starting point" in this endeavour. Whilst there are sure to be other candidates for this role, Dean's book is a strong contender and one that warrants attention.

The book is in three main parts. The first progresses through considerations of genetics, neurobiology and the evolution of mind by natural selection. In the second part, attention is turned to cognition, reason, rationality and collective action. Theories based on the mechanism of natural selection are again employed to account for the way we come to think and act. Finally, Dean draws the argument together within a framework provided by chaos and complexity theory. This framework is used to illustrate a way in which his preceding summaries of findings (from fields commonly considered in isolation) can be understood as part of a single account revealing the fractal nature of existence.

The book begins from Jellinek's early formulation of alcohol addiction as a function of biology mediated by psychological and sociological factors (Jellinek 1960). Although narrow disease based conceptions of 'addiction' are increasingly contested (for example, see Davies 1992 for a lucid critique from an attribution theory standpoint), this approach was an early and important development within addiction research. Jellinek's work provides a useful orientation for the book because of the way he discusses the inter-relatedness of different factors, and the way that similar underlying biology can manifest itself in quite different behavioural outcomes according to cultural context.

The book introduces several key concepts in substance use - craving, withdrawal, euphoria and tolerance before moving on to review the neurobiology of intoxication; providing a sketch of brain structure and neurochemistry along the way. This review begins with summaries of evidence from adoption studies, twin studies and molecular approaches and seeks to justify the place of genetics and neurobiology within an over-arching account of human nature. However, the need for additional levels of explanation beyond the genetic one is suggested by observations such as the increased level of both alcohol problems and abstinence among the children of 'alcoholics'.

This is the first of several summaries for different areas of the literature. Within each, Dean provides an accessible introduction, followed by a succinct and well referenced account of current understanding in the field. This general approach is a strength of the book and a useful one given its breadth. Dean makes few assumptions about the reader's familiarity with fields such as neurology, genetics, natural selection or chaos theory and so, prior to a more advanced discussion, he outlines all the main ideas. These sections are easily skipped by anyone who does not need such an introduction, and seem likely to lessen the risk that a reader - alienated by unfamiliar ideas - will abandon the book mid-way.

Extensive reference is made to the work of Plomin (1994). This moves beyond discussion of whether or not genetics influences behaviour concerning intoxication and towards a more quantitative account of its contribution. The concept of heritability statistics is introduced, to indicate ways in which the proportionate contribution of genetic factors to behaviour can be estimated. Intriguingly - to me at least - evidence is presented about the extent to which apparently social activities, such as peer selection, may have a quantifiable genetic component. The breadth of the book means that it works well in this way, sign posting other relevant literature for people accustomed to looking at that of only one discipline. Although Dean identifies the fact that work in the field of heritability statistics is still at a rather rudimentary stage, some of the possible developments are foreshadowed. Heritability statistics also contribute one parameter that would be of relevance in any agent-based simulation of substance use; a research interest that brought me to the book in the first place.

The discussion moves on to consider the means by which a process of natural selection, influenced by interactions with the environment, operates to produce the particular brain morphology for any individual. The example of variations at the level of the connections between neurons for genetically identical twins is used as part of an argument largely based on the work of Edelman (1992). This research is used to warrant the rejection of any completely deterministic model of brain (or mind) development. Within this section, a clear sense of the basis for a later argument concerning human nature's 'sensitive dependence on initial conditions' begins to develop. If a literary aside can be permitted, this discussion reminded me of an illustration of the differentiation between twins in The Black Hill by Bruce Chatwin (1982). In a subtle and beautiful tale of rural Wales, this novel traces the history of twin brothers who, despite sharing the same home almost throughout their lives, differ quite markedly in nature, their differences being attributed to chance events during their development.

The second section of the book provides an account of distinctions between instinct, reason and rationality, while further developing the argument concerning the multiplicity of factors shaping human nature.

The instincts are presented as the classical (Freudian) group of drives that form a basic (species-level) requirement for survival; including those that meet sexual and nutritional needs. Dean nevertheless emphasises the way that some individual variation within their expression can still occur. In this section, he also provides a simple thought experiment to explain the development of the instincts (p. 63) in terms that could form a direct basis for social simulation. Part of the appeal of the book is that there are a number of such points, where a reader interested in simulation might be inspired to move beyond thought experiments to real ones.

Edelman's (1992) 'primary consciousness' is used as the basis for an explanation of reason: defined as a pre-symbolic inner-knowing, based on value, memory and learning and limited to a recognition of the present. It permits sophisticated responses to dangers and rewards, shaped by means of natural selection - both within the species and the individual.

The works of Wittgenstein, as interpreted by Schatzki (1993), and that of Lacan, for whom Lemaire (1977) provides the same service, constitute the main points of reference for an account of rationality. Adaptive rationality is portrayed as the uniquely human, language-based, symbolic system that enables anticipation of the future and provides the particularly social influence on human nature. Finally, the work of Cosmides (1989) is introduced as a way of explaining the mechanism by which certain forms of social reasoning and problem solving may be selected for in a species with hunter/gatherer origins.

The importance of processes of natural selection is a central and recurring theme of the book. Dean indicates how they operate at each level within his account. He describes how selection takes place not only in the original Darwinian sense at the species level, where genetically fitter organisms tend to be selected, but also - for example - at the micro-level through selection and reinforcement of neural pathways during brain development (in response to environmental stimuli) or, through the selection of survival-related behaviour during the development of the 'primary consciousness' in an individual animal.

Although the second section of the book serves partly to provide a substantial amount of further evidence for an almost infinitely complex and hierarchical understanding of human nature, Dean also brings out important tensions between 'reason' and 'rationality'. To hugely over-simplify a more elaborate argument: reason - based in the 'remembered present' is portrayed in conflict with rationality - a uniquely human attribute deriving from symbolic representations of the future. The conflict this introduces broadly parallels the tension between the Freudian id and superego. This irreconcilability leads Dean to the assessment that "... the promise of a utopia based on science and education promised by the Enlightenment may have proved a false hope! "

The last section of the book summarises aspects of chaotic dynamics and complexity theory. It also explains the uncertainty that is inherent in non-linear systems. A conventional account is provided of key concepts such as self-similarity and sensitive dependence on initial conditions. The book moves on to consider the modelling of non-linear systems and the types of knowledge that this can generate, highlighting the contribution that simulation methodologies have to offer.

As might be expected in any book providing a commentary on the state of the art in a fast-moving field, events may have somewhat overtaken some of the statements in this section. So, for example, the assertion that there has been "no significant success in modelling ... individual action" is becoming questionable. Definitions of 'significant success' involve something of a value judgement, but arguably, the development of models like that of children's friendships (Alisch et al. 1997) provide examples of work that begins to do this in a useful way. Such points do not, however, detract from Dean's main thesis.

The book benefits from a clear conclusion that effectively draws together the different elements presented into a convincing case for viewing existence as fractal. Within a short book (171 pages), Dean presents arguments that are impressive in their scope and that I found persuasive, stimulating and potentially useful. He emerges as something of a polymath and, not being one myself, I am unable to assess fully his summaries and analysis for some of the literature on which he draws. However, as someone who has carried out research in social aspects of drug use for some years, I appreciate the way that he situates drug use at a number of levels; from the genetic to the social, and integrates these effectively in his analysis. The book provides a valuable foil to many unsatisfactory accounts in the drug use (or more usually misuse) literature which adopt a focus on just one level of analysis. Beyond this, Dean's choice of drug use seems apt as a case study within a broader project of working towards a theory of human nature. The book provides a fertile source of ideas for people using simulation within the social sciences. If the test of a good book is that it leaves the world looking a somewhat different place, then in my opinion Chaos and Intoxication passes with ease.


ALISCH L., S. Azizighanbari and M. Bargfeldt 1997. Dynamics of Children's Friendships. In R. A. Eve, S. Horsfall and M. E. Lee, editors, Chaos, Complexity, and Sociology. Sage Publications, London.

CHATWIN B. 1982. On the Black Hill. Macmillan, London.

COSMIDES L. 1989. The Logic of Social Exchange: Has Natural Selection Shaped How Humans Reason? Studies with the Wason Selection Test. Cognition, 31: 187-276.

DAVIES J. B. 1992. The Myth of Addiction. Harwood Academic, Reading, MA.

EDELMAN G. 1992. Bright Air, Brilliant Fire: On the Matter of the Mind. Penguin, Harmondsworth.

JELLINEK E. M. 1960. The Disease Concept of Alcoholism. Hillhouse Press, New Haven, CT.

LEMAIRE A. 1977. Lacan. London: Routledge and Kegan Paul, London.

PLOMIN R. 1994. Genetics and Experience: The Interplay between Nature and Nurture. Sage Publications, London.

SCHATZKI T. R. 1993. Wittgenstein: Mind, Body and Society. Journal for the Theory of Social Behavior, 23: 183-189.

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© Copyright Journal of Artificial Societies and Social Simulation, 1998