Chimps show similar personality traits to humans

Chimpanzees have almost the same personality traits as humans, and they are structured almost identically, according to new research.
The study identified five personality factors that combine differently in each individual chimpanzee: conscientiousness, dominance, extraversion, agreeableness and intellect.
This echoes a well-known five-factor model of the human personality, although the specific factors are slightly different, researchers at Georgia State University found.
"Our work also demonstrates the promise of using chimpanzee models to investigate the neurobiology of personality processes," said assistant professor of psychology, Robert Latzman, who led the research team.
The team started with a common tool for analysing chimp personalities called the Chimpanzee Personality Questionnaire.

The questionnaire is filled out by the chimpanzees' caregivers, who rate individual chimps in 43 categories based on their observation of the animals' daily behaviour.

The researchers analysed complete questionnaires for 174 chimpanzees housed at the Yerkes National Primate Center at Emory University. They ran extensive individual analyses to find out which traits tend to go together, and which combine to make more basic, fundamental 'meta-traits'.
The analysis showed that the most fundamental personality trait for chimpanzees is dominance - that is, whether an animal is a generally dominant and undercontrolled 'Alpha', or a more playful and sociable 'Beta'.
But those two big categories can be broken down statistically into smaller personality traits in ways that echo the personality structures researchers have repeatedly found in child and adult human subjects.

Alpha personalities, for example, statistically break down into tendencies toward dominance and disinhibition. Beta personalities, on the other hand, show low dominance and positive emotionality.
Further analysis shows these lower order traits also can be statistically broken down into their constituent parts.
Researchers found that many of those chimpanzee traits statistically correlate with the function of a neuropeptide called vasopressin.
Chimps who were born with a common variant in the genes that control vasopressin behaved differently than their peers, the males showing more dominance and more disinhibition, but the females less of both.
The research shows not only a neurobiological basis for personality, but an evolutionary basis as well. The neurobiological bases of personality can vary according to the biological sex of the subject, at least in chimpanzees, researchers said.

The study appears in the journal PLOS ONE.