Goodall’s findings confirmed: chimps have stable personalities
Decades after she was told to ignore her findings, Jane Goodall’s insight into chimps has been confirmed by 40 years of data. Stephen Fleischfresser reports.
Weiss, a psychologist from the University of Edinburgh, and his collaborators have made available a vast trove of data about one of the most famous communities of non-human animals on the planet.
The Kasekela community of eastern chimpanzees (Pan troglodytes schweinfurthii) live in the Gombe National Park in Tanzania. Kasekela became famous through Jane Goodall’s pioneering primate ethology of the 1960s, and her research into animal behaviour led her to the controversial claim that chimpanzees have individual personalities, much like humans.
So challenging was this idea at the time, that when Goodall first reported it to a respected ethologist, he replied that while it might be true, it was best that it be ‘swept under the carpet.’
Weiss and colleagues decided to revisit the Kasekela community with a focus on the now increasingly respectable idea of personality. The only previous attempt to quantify chimpanzee personalities was conducted by students and post-doctoral researchers in 1973, using a tool called the Emotions Profile Index (EPI) on a set of 24 chimpanzees. It was published in 1978.
Weiss set out to provide an even more comprehensive and up to date data set.
The chimpanzees of two communities in Gombe, Kasekela and Mitumba, have been subject to frequent observation -- in the case of Kasekela, since the 1970s. They are followed from dawn to dusk by local field assistants who systematically record their behaviour.
These assistants filled out a modified Hominoid Personality Questionnaire (HPQ), a tool for investigating primate personality that was originally derived from similar tools in human psychology, for 128 individual chimpanzees.
As well as the current population of these communities, assistants were also asked to complete the HPQ for chimpanzees that had died, but who they had known well, some of which were included in the original 1973 research.
Indeed “some of the older field assistants would have known these individual animals”, says Weiss. “I am certain that there are descendants of the original community in these data.” Taken together, this provides an unprecedented snapshot of various dimensions of chimpanzee personality.
Apart from the intellectual generosity of the publication, there was one striking finding.
As Weiss says, “personality ratings made by two different groups of individuals (the students and post-docs on the one hand and Tanzanian field assistants on the other), on two different questionnaires, and at two different time periods showed some degree of consistency in similar traits.”
This, he claims, is “yet more evidence, that chimpanzee personality ratings are getting at something 'real' about the individual animals.”
Weiss hopes that this data will “lay the groundwork for the systematic study of personality in wild chimpanzees” and help to explain individual differences in further research.
For more information on the life of Jane Goodall, a new documentary has been released telling the story of a female groundbreaker.