In this blog post, we explore the relationship between criminal tendencies and genetic factors from the perspectives of brain science and neurocriminology.
On September 13, 1848, blasting operations were underway on a large rock in the Green Mountains of Vermont, USA. Foreman Phineas Gage was tasked with placing explosives in the drilled holes. The procedure involved pouring sand into the loaded hole, lighting the fuse, and then retreating to a safe distance. However, that day, tragically, an accident occurred: the powder ignited before sand was poured into the hole. Phineas was not paying attention at that moment, and with a ‘Bang!’ the iron rod pierced his head. Remarkably, he survived, and thanks to Dr. Hallowell’s efforts, his life was saved. This incident drew significant attention from doctors, not only because Phineas survived but also because his personality changed completely after the accident. Phineas, who had been cheerful and gentle, began exhibiting mood swings and violent tendencies. The brain injury had caused a personality change. This was considered a case demonstrating the potential connection between the biological factor of the brain and the psychological factor of personality.
The discipline that studies such research is neuroscience. Neuroscience explores the various changes resulting from brain damage, and within this field, neurocriminology specifically studies the link between brain damage and crime. This article will focus on neurocriminology.
The origins of neurocriminology trace back to the Italian criminologist Cesare Lombroso. He argued that certain criminals possessed distinct physical characteristics, enabling their identification. For instance, he claimed thieves or rapists had unique physical traits. Furthermore, he asserted criminality was hereditary, believing individuals genetically predisposed to crime were born with specific physical features. However, his claims lacked clear statistical evidence and drew criticism for its links to eugenics and fascist ideology, ultimately fading into obscurity.
While neurocriminology tackles such sensitive and controversial topics, unlike Lombroso’s era, current research focuses not on individual appearance but on the possibility that the causes of crime lie in the brain and genes. That is, it posits that the difference between those who commit crimes and those who do not stems from brain structure. According to Professor Adrian Raine, author of ‘The Anatomy of Violence’ and a leading researcher in this field, the role of biological factors in criminal causation has been underestimated compared to environmental factors.
Indeed, research shows many criminals exhibit less evolved characteristics, such as specific palm line patterns or particular genetic mutations. For instance, the Monoamine Oxidase A (MAOA) gene mutation is frequently found in the families of criminals. A deficiency in this enzyme can impair the proper production of neurotransmitters that influence aggression, potentially promoting antisocial behavior. Furthermore, individuals with damage to the frontal lobe often struggle to control impulses. The brain region damaged in Phineas Gage’s accident was also the frontal lobe. A study analyzing the brains of 41 murderers found significantly lower activity in the prefrontal cortex. Such diverse biological factors, particularly the link between brain damage and crime, present a possibility worthy of serious consideration. However, some social scientists place greater emphasis on environmental factors, such as the criminal’s family environment or upbringing, rather than biological factors in causing crime.
The majority recognize that environmental factors significantly influence crime, and indeed, they often play a substantial role. Yet, contrary to this perception, there are also cases where the environment does not exert a major influence. For example, there is the case of Jeffrey Landrigan, who was adopted into a peaceful home and received a good education, yet persistently committed crimes. He met a criminal named Darren Hill in prison who looked exactly like him; it was later revealed that Darren Hill was his biological father, making the case a topic of discussion.
So, should we place greater emphasis on environmental factors or biological factors as the cause of crime? Until now, most societies have believed environmental factors cause crime. Indeed, most psychopaths or serial killers we encounter grew up in disadvantaged family environments and often experienced traumatic events in childhood. Furthermore, acknowledging biological factors as the primary cause of crime could imply that criminals are born that way, potentially linking to human rights issues. Consequently, biological factors have often been overlooked.
However, recent studies increasingly suggest the need to focus more on biological factors. Amid rising violent crimes in modern society, prevention has become more crucial than post-crime responses, making identifying the causes of crime a key task. Prevention based solely on environmental factors has limitations, so biological factors must also be considered. This does not mean scanning everyone’s brain to isolate those with high criminal potential, but rather keeping open the possibility of introducing brain scans for crime prevention. Professor Adrian Raine argues in his book that by around 2030, a crime prediction algorithm incorporating both genetic and environmental factors could predict criminal potential with over 70% accuracy.
We must no longer view this issue solely as a matter of human rights. Sufficient research and evidence have already been accumulated, and logical studies supporting this are underway. Of course, even if biological factors increase the likelihood of criminality, it cannot be concluded that the person will commit a crime. For example, while research shows that low levels of monoamines can trigger antisocial behavior, there are also individuals who exhibit antisocial tendencies without this trait, and cases where such tendencies have been overcome through environmental factors. However, this very point must be critically considered in crime prediction and prevention. For individuals with highly measured biological factors, the possibility of improvement through environmental factors must be kept wide open.
One reason social scientists oppose crime prediction based solely on biological factors is the concern that environmental factors could be neglected. If crime prediction relies only on biological factors, important environmental factors like racism or domestic violence could be marginalized. However, even with these concerns, a balanced crime prediction algorithm that comprehensively considers both biological and environmental factors would enable a more systematic response. Rather than judging solely based on a criminal’s brain structure, predictions should utilize a comprehensive analysis that incorporates environmental factors. If a crime prediction algorithm that reflects both environmental and biological factors in a balanced manner is introduced in society, it is expected to have a preventive effect.
The brain and crime are distinct yet deeply interconnected concepts. We must systematically elucidate the relationship between these two concepts and apply it to actual crime prevention. While limitations exist, such as human rights concerns and the impossibility of 100% prediction, strengthening the correlation between crime and the brain addressed by neurocriminology could lead to a safer society. If someone in your surroundings possesses a brain with a high potential for criminality, it would be preferable to take preventive environmental measures rather than overlook it. Crucially, one must not rely entirely on this prediction. Humans are predictable beings, yet they also possess an equally unpredictable aspect. Fundamentally, it is vital to create a social environment where crime is difficult to commit, and through this, we can hope for the development of a better society.
