Here's some unsettling news: new chimpanzee and neuroscience research is reinforcing the theory that our personalities are, in no small way, dictated by the structures of our brains. That is to say, we may choose how we act, but nature (not nurture) is deciding who we are in the most fundamental way.

According to a study recently published in the journal NeuroImage, researcher Roberts Latzman and his colleagues studied 107 chimpanzees' brains using magnetic resonance image (MRI) scans and also assessed each chimpanzee's personality by using a 41-item personality questionnaire. The results showed that chimps where were more extroverted and emotionally open with their compatriots had far greater volumes of gray-matter in the anterior cingulate cortexes of the brain, compared to chimps who kept to themselves.

Unsurprisingly, the anterior cingulate cortex for both hemispheres of the brain have been associated with maternal-infant interaction, emotional expression, and social motivation/learning for decades.

Interestingly, chimpanzees who were more dominant than their companions also had larger gray-matter volumes in the left anterior cingulate cortex in particular. Unpredictable chimps had higher gray-matter volumes in the right mesial prefrontal cortex, which helps track and consider rewards.

"Our results confirm the importance of neuroscientific approaches to the study of basic personalities," Latzman, a psychology researcher at Georgia State University, explained in a recent statement.

He added that "when compared to humans many of these associations are comparable in chimpanzees" -- a testament to our remarkable similarity to these great apes.

This of course, raises some heavy existential questions to boot. Are chimps introspective enough to try to change their personality? Is trying to change our own fundamental natures fruitless -- dictated, as they are, by the shape of our brains?

We may never have concrete answers for questions such as these, but that certainly won't stop researchers like Latzman from asking.

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