Aggression and Brain Functioning

Originating in the late 19th century and early 20th century with the ideas of Cesare Lombroso and Earnest Hooton, researchers have long taken an interest in understanding violent behaviors in terms of biological factors. These early works had racist overtones and were used to inform some unfortunate policies, including eugenics and euthanasia. Following the fallout from these movements, researchers began to distance themselves from exploring the biological correlates of aggression and instead focused on environmental influences. In the past several decades, however, literature again has begun to showcase studies that provide support for biological risk factors. Because the growing empirical evidence is assumedly free of political agenda and consistently demonstrates support for biological predictors of aggression, biological criminology has reappeared, and the field is growing.

Within the field of biological criminology, numerous factors have been linked to aggression, including neurobiology, psychophysiology, genes, and hormones. Of these influences, neurobiology, specifically brain functioning, is the topic presented in this entry. The importance of brain functioning in understanding aggression is underscored by one of the key researchers in the field, Adrian Raine, when he said, “It is now beyond doubt that brain deficits contribute in some way to antisocial and aggressive behavior” (2002, p. 4). Because of the central role of brain functioning in understanding pathways to aggression, it is apparent that empirical evidence of this nature is relevant when examining media violence. More specifically, media exposure may interact with brain functioning to predict aggressive tendencies. For example, if an individual is exposed to high levels of media violence and has neurobiological risk factors, then he or she may be at greater risk of becoming aggressive. This entry provides a summary of aggression-related constructs, a review of brain-imaging techniques, themes seen in the empirical evidence related to structural and functional factors, and ethical considerations.