Chimpanzee personality linked to anatomy of brain structures, study finds

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Chimpanzees' personality traits are linked to the anatomy of specific brain structures, according to researchers at Georgia State University, The University of Texas MD Anderson Cancer Center and University of Copenhagen.

The findings, published online in the journal NeuroImage in August, reveal that both gray- matter volumes of various frontal regions and gray-matter volume asymmetries (larger right versus left or vice versa) are associated with various . The results suggest the frontal cortex and asymmetries in this region of the brain play an important role in the neurobiological foundation of broad personality traits.

"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," said Robert Latzman, assistant professor in the Department of Psychology at Georgia State.

The researchers studied 107 chimpanzees' brains using magnetic resonance image (MRI) scans and also assessed each chimpanzee's personality by using a 41-item personality questionnaire. They found chimpanzees who were rated as higher for the personality traits of openness and extraversion had greater gray-matter volumes in the in both hemispheres of the brain. Chimpanzees who were rated as higher on dominance had larger gray-matter volumes in the left anterior cingulate cortex and right . Chimpanzees who rated higher on reactivity/unpredictability had higher gray-matter volumes in the right mesial prefrontal cortex.

All chimpanzees received MRI scans during their annual physical examination. For the personality questionnaire, the chimpanzees were rated by staff members who had worked with the animals for an extended period and felt they had enough experience for an accurate rating. Each item consisted of a single trait with a behavioral definition and a scale ranging from "least descriptive of the chimpanzee" to "most descriptive of the chimpanzee." The instrument consisted of five dimensions: extraversion, openness, agreeableness, dominance (opposite to the human trait of neuroticism) and reactivity/undependability (a dimension that includes content from the opposite side of the human traits of conscientiousness, agreeableness and extraversion).

Previous studies by this group suggest the existence of largely similar personality traits in humans and , but until this study, researchers had not explored the neuroanatomical basis of these traits in nonhuman primates.

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Chimpanzees show similar personality traits to humans, researchers say

Journal information: NeuroImage

Citation: Chimpanzee personality linked to anatomy of brain structures, study finds (2015, September 29) retrieved 20 July 2019 from
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Sep 30, 2015
The 5 factor model of personality tracks only those components of personality that are least likely to change over time, that is, those that are a result of genetic and physical properties.

One's actual personality is made up of four components or sources:
1) Genetic or 'behavioural phenotype' as measured by, for instance, the five factor model;
2) One's interaction with the environment through life (including operant and respondent conditioning);
3) the cultural environment in which one matures, lives and adheres to;
4) The current conditions (eg a passive or introverted person may become extroverted and controlling under some local condition, eg an emergency or where their children are in danger).

Thus the personality distinguishes you and your friends and the personality you have right now draws upon these four general areas, but (4), for instance, can change 100 times a day whereas (1) is stable through life although may not be in evidence unless 2,3&4 are controlled for.

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