In this blog post, we’ll examine what a biological approach to crime entails by focusing on cases of brain damage, and we’ll explore the causes of crime by looking at the relationship between frontal lobe damage and violent behavior.
A Biological Approach to Crime: A Look at Brain Injury Cases
Every day, we are constantly exposed to countless news reports online about crimes such as robberies and murders. So, what drives the criminals at the center of these crimes to commit such horrific acts? It is generally believed that social and environmental factors—such as a disadvantaged family background or upbringing—account for a significant portion of the motivation behind criminal behavior. However, there are limitations to explaining a criminal’s motives solely through these social factors.
Until the 20th century, there was a strong tendency to understand most criminal behavior through a sociological approach. However, neurocriminologists, including Adrian Raine, have argued that biological factors are also crucial for understanding violence and that a biological approach is necessary to understand the issue of crime more fundamentally. With the advancement of modern science, research on the human brain and genes has also progressed rapidly, and today these topics have become familiar to the general public. Consequently, the argument that human biological factors may be linked to the occurrence of crime is gradually gaining attention.
Looking at the 2014 Paldalsan dismemberment murder case in Suwon, the perpetrator was ultimately sentenced to life imprisonment. Although both the first and second instance courts sentenced him to life imprisonment, there was a difference in the courts’ assessments of the crime. The first instance court deemed it a premeditated crime, whereas the second instance court also considered the possibility that damage to the frontal lobe caused by a past fall had increased the defendant’s impulsivity. The court reviewed the criminal’s brain imaging data as a reference, thereby demonstrating the need to examine the causes of crime from various perspectives. Of course, even today, the view that brain damage alone can determine the cause of a crime is not widely accepted; it is generally understood that crime results from a complex interplay of biological and environmental factors. Let us, then, examine which functions of the human brain are related to such behavior.
Frontal Lobe Damage and Personality Changes
In the 19th century, Phineas Gage was a railroad construction supervisor in the United States who was highly responsible and had good interpersonal skills. While working on a railroad project, he had just finished setting explosives and was turning away when a sudden explosion occurred. A steel rod weighing approximately 6 kg and measuring about 1 m in length pierced his head from the lower left to the upper right. The rod passed through his upper jaw and left eye, penetrated his frontal lobe, and then pierced his skull before falling about 25 m away.
Remarkably, he did not lose consciousness and had recovered enough to return to work two months later. However, his personality changed significantly after the accident. Although there were no major changes in his language skills, intelligence, or sensory abilities, he—who had previously been highly responsible and cautious—began to exhibit impulsive, rough behavior and a tendency to disregard social norms. The case of Phineas Gage is a classic example illustrating how damage to the prefrontal cortex can affect a person’s behavior and personality, and it remains a subject of significant research in the fields of neuropsychology and neuroscience to this day.
Another example is Herbert Weinstein, the head of an advertising agency, who committed murder in 1991 during an argument with his wife. His defense attorney, questioning why he—who had no history of violence—had suddenly committed such a crime, ordered MRI and PET scans. The results revealed significant structural abnormalities in the prefrontal cortex. Researchers suggested that this structural damage may have affected his judgment and impulse control. However, this case is also interpreted as one of several contributing factors rather than as evidence that solely explains the cause of the crime.
The cases of Phineas Gage and Herbert Weinstein both demonstrate that extreme and antisocial behavioral traits can emerge following damage to the frontal lobe. So, what role does the frontal lobe play in the brain that allows it to exert such a significant influence on behavior and personality?
Frontal Lobe Function and Crime Research
The prefrontal cortex is a region located at the front of the brain, near the forehead, and is a critical area responsible for executive functions such as judgment, planning, impulse control, and social behavior. Through the prefrontal cortex, humans can synthesize various types of information, predict the consequences of their actions, and make decisions that align with social norms.
Long-term research has consistently reported an association between prefrontal cortex damage and antisocial behavior. Clinical case studies show that patients with frontal lobe damage resulting from accidents sometimes exhibit callous or irresponsible tendencies and increased aggression.
A study analyzing the brains of individuals who consistently exhibit antisocial behavior using MRI reported that, while there was no significant difference in overall brain size compared to the general population, the volume of gray matter in certain areas of the prefrontal cortex was, on average, lower. Gray matter consists of densely packed nerve cells, and the prefrontal cortex plays a particularly important role in judgment and impulse control.
In a study that conducted a detailed analysis, these differences were even more pronounced in the orbitofrontal and medial prefrontal regions. These areas are similar to the regions damaged in Phineas Gage’s accident. Furthermore, some studies have suggested that structural abnormalities in the ventral regions of the prefrontal cortex may be associated with antisocial behavior.
However, these findings merely indicate a statistical trend; they do not imply that individuals with prefrontal lobe damage will necessarily become criminals or engage in violent behavior. Currently, neuroscience and criminology understand that crime results from the combined influence of various factors—including biological factors, upbringing, education, social experiences, and mental health.
There are various approaches to explaining violence. This article has examined the causes of crime primarily from a biological perspective, focusing in particular on how frontal lobe damage can affect behavior and impulse control through several case studies. In the future, neurocriminology research has the potential to lead to a more accurate understanding of the causes of crime and to be applied in various fields, such as mental health management, early intervention, and risk factor assessment. However, based on current scientific evidence alone, it is insufficient to conclusively determine or predict an individual’s likelihood of committing a crime based solely on specific biological characteristics; a comprehensive approach that considers social and environmental factors alongside biological ones is essential.
