The Neurobiology of Personality

by Rabiya S. Tuma

November, 2006

The structure of a person’s brain predicts core qualities of his or her early personality, new research suggests.

Researchers led by Nick Allen, an associate professor of psychology at the University of Melbourne, Australia, tested 153 12- and 13-year-olds in two ways. First they asked the volunteers to answer a questionnaire that explores four traits thought to be integral to an individual’s personality: frustration when interrupted or blocked from completing a task, ability to voluntarily regulate their behavior and attention, strong interest in novel or intense activities, and desire for intimate relationships. The researchers then used magnetic resonance imaging to take detailed pictures of each subject’s brain.

Comparing the two measures, Allen’s team found that the size of specific brain regions correlated with some aspects of temperament based on the questionnaire. For example, those who had a larger dorsal anterior cingulate cortex tended to have better control of their behavior regulation and attention and less tendency for frustration. 

The data suggest that some aspect of personality is encoded in the brain structure, Allen said, though much of it will be generated by an individual’s environment and experiences. “The fact these differences in people are observable in the brain fairly early in life … suggests that this is one of the ways in which personality is inherited,” he said. 

Additionally, scientists know that the brains of people with mental illnesses are often different from those who are healthy. By following these volunteers through adolescence and into young adulthood, Allen’s team hopes to learn whether the brain structure differences precede mental illness or occur as a consequence of it. Either way, future findings may help guide treatment and prevention.