This chapter tests and refines a developmental taxonomy of antisocial behavior, which proposed two primary hypothetical prototypes: life-course persistent offenders whose antisocial behavior begins in childhood and continues worsening thereafter, versus adolescence-limited offenders whose antisocial behavior begins in adolescence and desists in young adulthood (Moffitt, 1993). Two of our previous reports have described clinically defined groups of childhood-onset and adolescence-onset antisocial youths in the Dunedin birth cohort during childhood (Moffitt & Caspi, 2001) and at age 18 (Moffitt, Caspi, Dickson, Silva, & Stanton, 1996). Recently we followed up the cohort at age 26, and here we describe how the two groups of males fared in adulthood. In so doing we test a hypothesis critical to the theory: that childhood-onset, but not adolescent-onset, antisocial behavior is associated in adulthood with antisocial personality, violence, and continued serious antisocial behavior that expands into maladjustment in work life and victimization of partners and children (Moffitt, 1993).

THE TWO PROTOTYPES AND THEIR PREDICTED ADULT OUTCOMES

According to the theory, life-course persistent antisocials are few, persistent, and pathological. Adolescence-limited antisocials are common, relatively temporary, and near normative. The developmental typology hypothesized that childhood-onset versus adolescent-onset conduct problems have different etiologies. In addition, the typology differed from other developmental crime theories by predicting different outcome pathways for the two types across the adult life-course (Caspi & Moffitt, 1995; Moffitt, 1993, 1994, 1997).

INTRODUCTION

The expression that time changes everything could be no more true than in the case of the integration of human biology and aggressive behavior. Earlier perspectives concerning the integration of biology and behavior were riddled with ideas of determinism and the preponderance of nature over nurture. Biological processes were viewed as causal agents in behavior. Current perspectives view biology and behavior as evolving in dynamic interaction throughout ontogeny (Lerner, 2002; Magnusson, 1999; Magnusson & Stattin, 1998; Susman, Dorn, & Schiefelbein, 2003; Susman & Rogol, 2004). These perspectives suggest that levels of existence, from the molecular and genetic to the macro social levels, co-dependently produce the uniqueness of individuals.

The chapters in this volume attest to how the decline in the perennial debate about nature and nurture has facilitated the acceptance of new theoretical and empirical developments on biological parameters of aggressive behavior. First, the chapters show that explaining a complex human behavior, such as aggression, now is not the purview of any one disciplinary perspective. Throughout the history of the study of development, philosophers and scientists have been devotees of either a biological or a social perspective on the causes of aggressive and criminal behavior. In the past few decades, a clear distinction existed between biological, behavioral, and social science perspectives on aggression. The prevailing view was that biologists search for universals to explain human behavior and differences among species. In contrast, behavioral and social scientists focus on social processes and search for individual differences among persons.

INTRODUCTION

Over 50 years ago, Bateson argued strenuously that the concept of individual behavior is vacuous because people act in the context of others' behavior, concluding that social psychology properly should study “the reactions of individuals to the reactions of other individuals” (Bateson, 1958, p. 175). Nonetheless, as the above quotes from his and others' ethnographies suggest, individual differences in behavior are ubiquitous and universally attributed to temperamental differences even as socialization practices are predicated on an equally universal assumption of nurture's role in behavior development.

This volume is an outgrowth of a memorial conference to honor the scientific contributions and accomplishments of Robert B. Cairns, internationally recognized for his pioneering efforts as an interdisciplinary developmental scientist. His theories and research in humans and animals provided a template and direction for future research in the developmental sciences and the psychobiology of aggression. This perspective integrated biology with psychological development, emphasizing the dynamic interactions among biological, psychological, and environmental influences on development and behavior. Cairns described a conception of human developmental processes, characterized by biobehavioral organization and involving reciprocal interactions of bidirectionality, plasticity, and gene–environment relationships. This conceptual framework provided an expanded array of multiple biological and behavioral levels as it applied to aggression, offering a refreshing departure from the very limited unidimensional belief in the deterministic role that unfolding biology exerts on behavior (see Figure 1.1; Cairns, 1996).

In earlier volumes, we presented various research approaches to the biology of aggression (Stoff & Cairns, 1996) and provided a comprehensive review of research on many aspects of antisocial behavior (Stoff, Breiling, & Maser, 1997). This volume updates those works, principally from a developmental psychobiological viewpoint of aggression, emphasizing modern neuroscience approaches that focus not only on “bottom-up” causality (e.g., molecular processes involving genes, cells, and synapses) but also on “top-down” causality (e.g., more molar processes mediated by experiences).

In the last quarter of the 20th century, Robert Cairns helped to transform psychology. In doing so, he rescued it from a virulent susceptibility to reductionism. Standing on the shoulders of great psychologists of the first half of that century (James Baldwin and Kurt Lewin most readily come to mind), he created a truly interdisciplinary environment at Chapel Hill. The Carolina Consortium on Human Development became an international crossroad for the establishment of a new synthesis termed developmental science. A legion of graduate students, postdoctoral Fellows, young faculty, and many senior investigators emerged from this oasis with a deeper, more nuanced understanding of human development. By formulating sound theory and exacting the highest standards for basic research, Cairns and his colleagues moved the field into a realm in which social behavior was not reducible: not to motivations or environmental contingencies any more than to neurons or molecules. Behavior was not sacrificed to biology, nor was it glorified to the environment. Rather, a coherence of behavior and biology was refined in a manner that was intellectually robust and scientifically challenging. Evolution, genetics, ontogeny, and social relationships were interwoven with honesty and with appropriate appreciation for the subtleties involved.

In this volume a group of accomplished protégés and admirers of Cairns explore the nature of aggression, an area of social behavior that most intrigued him. How is it that a social species tolerates aggression?

Toward an integrative understanding of behavioral development, one sufficient to address how complex behaviors emerge over the course of development, the field of developmental psychobiology has advanced in recent years to transcend dichotomous views of cause and effect or nature versus nurture. Beyond parsing the stuff of life into genetic or environmental sources, contemporary theorists are likely to envision three-dimensional interactive webs, lifelines or fabrics of intertwined strands, recursive fractal forms, and dialectical transformations across levels of organization as conceptual models for aspects of developmental processes (Cairns, 1996; Gottlieb, 1998; Hood, 1995; Lerner, 1998; Michel & Moore, 1995; Thelen & Smith, 1998). Whether these models are generative in revealing new properties of specific developmental domains is an active question. For present purposes, they bring an expanding range of issues to the research agenda for a multidisciplinary approach to the study of development. A consideration of aggressive behavior as enfolded within a dynamic developmental manifold may contribute to the goal of a fully integrative account. This is the present project.

A critical issue for proceeding is how to construe the ubiquitous and continuous bidirectional flow of actions that comprise social interchanges. Social environments affect individual development even as individuals choose and shape their changing social environments.

BRIAN PLASTICITY AND SOCIAL DEVELOPMENT

The notion of plasticity in relation to biological and behavioral development is not a new one. Even when very little was known about brain structure and function and long before the advent of modern molecular and neuroanatomical techniques, scientists recognized that the brain had the capacity to adapt and change in response to environmental input. Already in 1892, William James stressed the importance of brain plasticity in the organization of habits:

James's intuition was confirmed in the 1960s when a group of scientists provided the first empirical evidence of environmentally induced alterations in brain chemistry and structure (Diamond, Krech, & Rozenzweig,1964; Krech, Rozenzweig, & Bennett, 1960; Rozenzweig, Krech, Bennett, & Diamond, 1962). Importantly, it was shown that these neurobiological alterations were associated with enhanced behavioral and particularly cognitive functions.