Ratings taken nearly 40 years apart of the chimpanzees of the Gombe National Park in Tanzania, made famous by Jane Goodall, show evidence of personality stability, reports a paper published online in Scientific Data this week. The study compares recent personality trait data to previous data recorded in the 1970s and, it is hoped, will lead to better understanding of the evolution of personality in chimpanzees and other primates, including humans.
Our understanding of personality variation and its evolutionary significance among primates is limited, because only a small number of species have been studied in the wild. Jane Goodall’s vivid depictions of the personalities of the eastern chimpanzees (Pan troglodytes schweinfurthii) at Gombe National Park drew the attention of a global audience, yet only one attempt has been made to systematically quantify their personality traits. This 1973 study involved researchers rating 24 chimpanzees, who had known the researchers for several months to several years, on a personality questionnaire.
Here, Alexander Weiss and colleagues present ratings data that describes the personalities of 128 wild eastern chimpanzees from the same National Park. The personalities of the chimpanzees were rated by Tanzanian field assistants who followed individual chimpanzees for years and collected detailed behavioural observations using 24 different measures (such as excitable, sensitive, helpful, curious) from a well-recognised chimpanzee personality questionnaire. The authors suggest that the correlations between ratings from their study and the personality measures assessed nearly 40 years earlier indicate the existence of stable personality traits in the animals (where there is some change in personality traits over time, but that the traits remain relatively stable, in a similar way that tall children grow over time, but they tend to grow into tall adults).