Whether humans are inherently evil or conditioned to be evil has been debated by philosophers for centuries. However, biological psychology - the study of how the structures of human biological systems and their functions influence humans’ behavior and mental processes - can provide insight into this debate. Based on numerous case studies and brain scans, researchers found that incarcerated men who attempted or committed homicide had brain activity that differed from the average human brain.
Adrian Raine, a British psychologist and professor of criminology at Richard Perry University scanned the brains of 22 murders who had been judged incompetent to stand trial using positron emission tomography (PET). PET detects photons emitted by a radionuclide in the
organ or tissue being examined (in this case, the brain). He found that their brains had deficits in their prefrontal cortex. Reduced prefrontal cortex functioning can cause a loss of control over brain structures such as the amygdala, which is responsible for aggressive and fear responses. In addition, prefrontal cortex damage has been linked with emotional and aggressive outbursts, loss of self-control, poor social judgment, and the failure of intellectual flexibility. These associations between poor prefrontal cortex function and violence could be enhanced or diminished by environmental and social factors such as childhood devoid of attention and love.
In addition, neuroscientists at the University of Chicago observed reduced Gray matter and functioning of the corpus callosum. Gray matter enables individuals to control movement, memory, and emotions. The corpus callosum is a band of white nerve fibers that allows communication between the left and right cerebral hemispheres. Reductions of gray matter in regions of the brain associated with emotional processing, behavioral control, and social cognition means fewer cells, neurons, and glia to process information such as empathyPoor connection between hemispheres may mean that the right hemisphere, which is involved in the generation of negative emotion, may be less regulated and controlled than the left hemisphere.
With the rise of mass shootings in the United States, it is evident that brain imaging research on serial killers would benefit traditional mental health care institutions, whose preventive-to-aggressive-behavior methods were ineffective against famous mass shooters, including Nikolas Cruz of the Stoneman Douglas High School shooting and Eric Harris of the Columbine High School shooting. For instance, selective serotonin reuptake inhibitors (SSRIs) are widely used antidepressants in such institutions. However, they can cause increased activity in brain areas like the amygdala, which, as stated before, is responsible for aggressive responses. Thus, psychiatrists in the future should consider studies such as the ones conducted by the University of Chicago when prescribing medicines for people with violent behavior.
In conclusion, there is a fine line between criminals’ behavior due to poverty, unemployment, child abuse, and their brains’ dysfunctional structures, such as the prefrontal cortex. However, brain-imaging research on violence proves the correlation between specific brain abnormalities and violence, which could profoundly challenge society’s way of conceptualizing crime as deviant behavior that violates prevailing norms. What if, in their brains, it is the normal thing to do?