A new study has shown that psychopathic people have a larger striatum area in their brains.
Using MRI scans, neuroscientists discovered that psychopathic people have a 10% larger striatum than normal people—a cluster of neurons in the subcortical basal ganglia of the forebrain. This represents a clear biological distinction between psychopaths and non-psychopathic people.
Neuroscientists from Nanyang Technological University (NTU Singapore), the University of Pennsylvania, and California State University have discovered a biological distinction between psychopaths and non-psychopaths.
The researchers used Magnetic resonance imaging (MRI) scans in their study.
It turned out that the striatum, an area in the forebrain, was 10% larger in psychopathic subjects compared to a control group with low or no psychopathic features.
Psychopaths, or those with psychopathic qualities, are known to have a selfish and antisocial disposition.
This is often characterized by a lack of guilt for their actions, a lack of empathy for others, and in some cases, criminal tendencies.
The striatum, a subcortical region of the brain that is part of the forebrain and encompasses the entire cerebrum, coordinates numerous elements of cognition, including motor and action planning, decision making, motivation, reinforcement, and reward perception.
Previous research had shown that psychopaths have an overactive striatum, but the effect of its size on behavior has yet to be confirmed.
The new research shows that there is a significant biological difference between people who exhibit psychopathic tendencies and those who do not.
While not all people with psychopathic qualities eventually break the law, there is a correlation between crime and the criteria they have. We can even call this relationship a strong one.
It is thought that understanding the role of biology in antisocial and criminal behavior will contribute to the processes experienced.
To conduct their study, neuroscientists scanned the brains of 120 participants in the United States.
He interviewed individuals using the Psychopathy Checklist-Revised, a psychological assessment tool, to identify the presence of psychopathic traits.
Assistant Professor Olivia Choy, a neurocriminologist at NTU's School of Social Sciences, said: "The results of our study help improve our knowledge of what underlies antisocial behaviors such as psychopathy.
"In addition to social environmental influences, we found it important to consider that there may be differences in biology, in this case, in the size of their brain structures, between antisocial and non-antisocial individuals."
Professor Adrian Raine from the University of Pennsylvania Department of Criminology, Psychiatry and Psychology explains as follows;
“Since biological traits such as the size of a person's striatum can be inherited from a parent, these findings provide additional support to neurodevelopmental perspectives of psychopathy.
The brains of these criminals do not develop normally during childhood and adolescence”.
Professor Robert Schug, co-author of the study, from the School of Criminology, Criminal Justice and Emergency Management at California State University in Long Beach added:
“The use of the Revised Psychopathy Checklist in a community sample remains a new scientific approach:
It helps us understand the psychopathic traits of individuals who are not in prisons and prisons, but rather walk among us every day.”
The explanations of an associate professor from the Department of Psychology at the University of Alabama, who was not involved in the research, are as follows;
“This is because psychopathy is associated with structural differences in the striatum, a brain region in various processes important to cognitive and social functioning.
Future studies will be needed to understand the factors that may contribute to these structural differences.”
The results of the study were recently published in a peer-reviewed academic publication. Journal of Psychiatric ResearchPublished in .
Greater Striatum Means Greater Desire for Stimulation
Various results were obtained from the analyzes of MRI scans and interviews for psychopathy screening.
Thanks to these results, the researchers linked having a larger striatum to an increased need for stimulation through excitement and excitement, and a higher probability of impulsive behavior.
The striatum is part of the basal ganglia, which consists of clusters of neurons deep in the center of the brain. The basal ganglia receive signals from the cerebral cortex that distinguish cognition, social behavior, and what sensory information requires attention.
However, in the last two decades, understanding of the striatum has expanded, providing clues that the area is linked to difficulties in social behavior. Previous studies have not addressed whether striatal enlargement is observed in adult women with psychopathic features.
In a study of 120 individuals, neuroscientists say they examined 12 women and observed for the first time that psychopathy is linked to an enlarged striatum in women as well as men.
In human development, the striatum typically shrinks as a child matures, suggesting that psychopathy may be related to differences in how the brain develops.
Assist. Prof Choy said, “There is still a need for a better understanding of the development of the striatum. Many factors are likely at play as to why one individual is more likely to have psychopathic traits than another individual.
The Importance of Environmental Factors in Psychopathy
Psychopathy may be linked to a structural abnormality in the brain, which may be developmental. At the same time, it is important to recognize that the environment can also have effects on the structure of the striatum.”
Prof Raine added: “We've always known that psychopaths go to extreme lengths to seek reward, including criminal activities involving property, sex and drugs.
We now find a neurobiological basis for this impulsive and arousing behavior in the form of enlargement of the striatum, a key brain area associated with rewards.
The researchers hope to conduct further research to find the causes of enlargement of the striatum in individuals with psychopathic traits.
Ref: “Larger striatal volume is associated with increased adult psychopathy” by Olivia Choy, Adrian Raine and Robert Schug, 6 March 2022, Journal of Psychiatric Research.