What makes you act the way you do? A new study conducted by Colin G. DeYoung and colleagues from the University of Minnesota suggests that certain personality traits are related to certain brain structure sizes.
The study finds that extraverts have an enlarged orbitofrontal cortex, which is the part of the brain that registers rewards. These individuals are cheerful, assertive, and competitive.
However, the study could not find cause-and-effect, meaning scientists are still unsure whether the brain structure causes the personality trait or the trait causes the changes in brain structure, as personalities are (for the most part) constant, but do possess the ability to change over time.
The study used an MRI scan of over 100 people after each individual’s personality type had been determined by the Big Five: extraversion, agreeableness, conscientiousness, neuroticism, and openness/intellect.
Those identified as conscientious (hard working and self-disciplined) also had a large lateral prefrontal cortex.
Those identified as neurotic (negative and depressed) had a smaller medial prefrontal cortex, which regulates emotion.
Those identified as open (creative) actually had no drastic changes in brain structures.