A new study suggests that the personality traits of the chimpanzees depend on specific brain structures. Earlier studies on humans have linked brain structures to personality traits, but this recent study is the first to test the theory on animals.
Researchers at Georgia State University, the University of Texas M.D. Anderson Cancer Center and the University of Copenhagen studied the brain scans of 107 chimpanzees and assessed them using a 41-item personality questionnaire that was answered by their handlers. The questions aimed to measure five personality traits including extraversion, openness, agreeableness, dominance, and reactivity or undependability.
The analysis showed that the chimpanzees that rated high in openness and extroversion had greater gray matter volume in the anterior cingulate cortex (ACC) in both hemispheres of the brain. The ACC plays a role in rationality, such as reward anticipation, decision-making, empathy, impulse control and emotion.
The dominant chimpanzees showed greater gray matter volume in the left hemisphere of the brain. Those who have greater gray matter volume in the right hemisphere, on the other hand, are more likely to become reactive or unpredictable.
"Our results confirm the importance of neuroscientific approaches to the study of basic personalities and suggest that when compared to humans many of these associations are comparable in chimpanzees," Robert Latzman, assistant professor of psychology at Georgia State, said in a university news release.
The study was published in the journal NeuroImage.
