Juvenile Delinquency: Understanding the Origins of Individual Differences

How can we best chart a course for prevention and intervention to reduce juvenile delinquency? Juvenile Delinquency: Understanding the Origins of Individual Differences provides some of the answers to this question, although not in the pragmatic way that some readers might prefer. The book's authors, Vernon Quinsey, Ph.D., and his colleagues, warn that whatever we do about delinquent youths, our approach ought to be informed by a sound theory and a clear view of what we know empirically about delinquency. This book offers a theoretical and empirical perspective toward that end.

The authors use evolutionary psychology—in their words, "a Darwinian selectionist habit of thought"—as the main ingredient in a cocktail of information from biology, psychology, sociology, and criminology to create a blended view of what causes juvenile delinquency. That main ingredient is the focus of the first two chapters, which provide a primer on evolutionary biology and behavioral genetics. These chapters are well written but heavy going, and some readers might fear that this genetic perspective on aggression can only end badly—changing the gene pool takes a long time. But perseverance is recommended and rewarded. This foundation for the cocktail, while stiff in undiluted form, offers the interesting texture for later chapters as other ingredients are added.

Chapters 3 through 6 describe developmental features of adolescence that are relevant for understanding delinquency, a taxonomy of delinquency, sex differences in aggression, and implications of the authors' theoretical perspective for delinquency prevention and intervention.

Even if one doesn't take to the evolutionary theme, the chapter on taxonomy is an excellent, concise review of the evidence that delinquent youths are not a homogeneous group. A small percentage of such youths continue to endanger us well into their adult years. However, a majority are "adolescence-limited" delinquents who "age out" of serious illegal behavior by adulthood. The authors' evolutionary theory has something to say about them, but not much. The greater focus is on chronic juvenile offenders—approximately 10 to 20 percent of delinquent youths—whose illegal behaviors are the beginning of a "life-course-persistent" criminal career. This book is primarily about the more dangerous few.

The chapter on prevention and intervention usefully and concisely summarizes what we know about the effectiveness of available responses to aggression during early childhood and adolescence. The book's evolutionary perspective does not take us anywhere new in this regard. But nor does it inhibit treatment efforts. The authors point out that the inheritance of antisocial potential does not mean that antisocial behavior is necessarily resistant to modification, and they show how some of our current and most promising interventions are consistent with the book's theory.

A few things are missing. Mental disorders other than conduct disorder and attention-deficit hyperactivity disorder are rarely mentioned, despite the fact that about 60 percent of youths in juvenile justice settings meet criteria for at least one of these disorders, even when conduct disorder is excluded (1). There is no review of the new magnetic resonance imaging (MRI) studies in developmental neuroscience that show that the frontal lobe is still maturing during adolescence (2), offering potential implications for understanding youths' delinquent behaviors.

These omissions, however, do not diminish the value of this book as a creative blend of data from diverse fields, enlivened by an evolutionary twist. Active readers can flavor the whole by adding their own splash of psychiatry to taste.