A recent study published in Brain and Behavior has sought to explain the connection between reward centres in the brain and “appetitive” aggression in individuals who regularly engage in violent activities (i.e. martial arts).
Appetitive aggression can be described as violent behavior that’s committed for its own sake, as opposed to reactive aggression (e.g. defensive rage), or proactive or goal-oriented aggression (e.g. robbing a store). In other words, certain individuals may find violent behavior fascinating, exciting or pleasurable, and so seek it out.
In the study, 16 martial artists and 24 untrained control subjects were given a task that involved viewing images of either neutral social interactions (e.g. people having coffee) or violent scenes (e.g. people fighting). Subjects’ individual aggressiveness was inferred using a questionnaire, while brain scans performed during the task allowed researchers to determine which brain areas experienced the most activation.
Compared to the control subjects, the martial artists in question demonstrated increased activation in the left amygdala, a part of the brain suspected to play a role in reward systems. The study failed to demonstrate, however, activation of other important cerebral centres like the nucleus accumbens, whose role in reward is both fundamental and better understood.
As the authors readily admit, the study has some methodological limitations. The sample size is quite small, all male, and includes a variety of martial arts (among them Muay Thai, kung-fu and boxing).
Additionally, the study’s authors made some important assumptions that bear examination. For example, it’s explicitly assumed that martial artists are predisposed to perceiving violence as pleasurable, and thus likely to seek it out in socially acceptable forms. However, the participants themselves may hold a very different opinion of their behavior, especially considering that many martial arts prioritise inner-peace, self-awareness, and the avoidance of aggression when possible. Similarly, appetitive aspects may be more readily related to, for example, enjoyment from physical activity and competitiveness.
For the moment, much remains to be learned about what motivates individuals to participate in violent behavior. Activation of some, but not all of the brain structures involved in reward means that we’ve only seen a piece of the whole picture. The study does confirm, however, that some neural differences do exist, and that more research is needed to understand them.
The study, “Neurobiological correlates of violence perception in martial artists“, was authored by Maria Schöne, Stephanie Seidenbecher, Leonardo Tozzi, Jörn Kaufmann, Hendrik Griep, Daniela Fenker, Thomas Frodl, Bernhard Bogerts, and Kolja Schiltz.