Rafter's The Criminal Brain is a superb intellectual and cultural history of biological theories of crime, inspired by the author's desire to find "a new or third way" to integrate biological, sociological, and historical approaches to crime (251). Rafter's study, however, is largely a cautionary tale about the potential dangers of searching for biological explanations of criminal conduct. Criminologists in the nineteenth and early twentieth centuries turned to phrenology, criminal anthropology, evolutionary theory, intelligence tests, and analyses of body types to understand crime in a manner that reified the differences between criminals and non-criminals. Adopting a "medical model" of crime, they focused on the physical traits that they believed distinguished criminals and largely ignored the circumstances in which criminals lived (242).
Most early biocriminologists tried to reduce "the complexities of criminal behavior to a single biological factor," such as the size of the frontal lobes of the brain, the shape of the skull, or the capacity to learn (243). Most of them were also convinced that biology was destiny. They believed that interactions between biology and the environment played little, if any, role in shaping the behavior of criminals. Given their assumptions, it is not surprising that many biocriminologists embraced eugenics, since they believed that criminals represented a lower, atavistic state of human evolution. Nor is it surprising that behavioral scientists [End Page 123] lost interest in biological explanations of crime once they had witnessed the atrocities committed by the Nazis and other eugenicists in the name of biocriminology.
In Rafter's opinion, the changes in biology since World War II will make it possible to create a "biosocial" criminology that avoids the pitfalls of early biocriminology. "For the first time," she writes, "there is a genuine possibility for collaborations between social scientists and cognitive, genetic, and neurological scientists working on crime" (246). Biologists no longer belittle "the possibility that social factors might affect criminal behavior," because the ways in which genes are expressed "depend on social factors" (243, 246). Brain damage, lead poisoning, childhood traumas, stress, poor diet, drug abuse, and other factors can help to predispose people to antisocial behavior. Genes play a role in human behavior, but they do not determine it. Furthermore, although biologists no longer believe it possible to draw a sharp physical line between criminals and non-criminals, between "us" and "them" (245), Rafter is excited by recent research on acquired biological deficits, cognitive deficits, genetics, and neuroscience. This new work will not improve our understanding of crime, however, unless social scientists "acknowledge that biological factors affect crime" (246).
Rafter spends little time on recent works in primatology that suggest that many criminal behaviors—theft, deceit, sexual assault, and homicide—have deep evolutionary roots. She spends more time on the differences between criminals and non-criminals than on the potential of all humans for criminal behavior. Nor does she consider at length the evolution of moral reasoning, which gives humans the capacity to define certain kinds of behaviors as criminal. The Criminal Brain is nonetheless an outstanding book, which should be required reading not only for criminologists, but for all scholars who would like to engage scientists and social scientists in a more fruitful dialogue about human behavior.