For decades, ape experts have searched for cognitive abilities in this animal group that are similar to humans, in order to understand how our own complex abilities evolved.
Much of this research is based on the idea that if a particular ability – such as using gestures to communicate – is found only in species that are closely related to us, then it’s likely that the trait evolved relatively recently in our evolutionary history.
But a team at Leuphana University of Lüneburg argue that this is a static way of considering cognitive ability.
“There’s a lot of experiences that … contribute to the precise nature of how [an individual’s] cognition is structured and organized,” says Manuel Bohn, a developmental psychologist at the university.
“We have these, kind of, developmental and individual differences perspectives for humans. And so, we thought this was clearly missing in great apes.”
The team studied 48 apes – bonobos, chimpanzees, gorillas, and orangutans – in a series of cognitive tasks over 18 months.
The findings, published in Psychological Science, revealed that individual apes differed from one another (even among the same species) and these differences were fairly stable over time. The findings also showed that factors such as upbringing, life experiences, sex, social group and previous exposure to humans affected performance.
In other words, the study reveals that apes have individual personalities and cognitive strengths – just as humans do.
“That’s also often the way that we think about individual differences in humans, like they are stable traits or some property of an individual. And we find pretty good evidence that this is the case here in great apes as well,” explains Bohn.
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A surprising finding indicates that ape intelligence may be organised differently from human intelligence.
The researchers learned that, when it comes to apes, being good at tasks that relied on social cues (such as attention following) didn’t predict being good at other social cue-based tasks.
By contrast, the results of non-social tasks (such as reasoning) were more closely correlated.
“We do not find these clusters that we expect to be there from a human perspective, which I think is really interesting and thought-provoking,” Bohn explains.
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Further research is needed to understand how ape cognition is put together, without assuming that human cognition is the template.
“We don’t have assessment tools that have been particularly built to assess the different aspects of great ape cognition,” Bohn adds.
He noted that future research could further assess the tools that are currently used to measure ape cognition, which could allow scientists to document cognitive development in apes – and how it varies in individuals.
Read the full paper here: Individual Differences in Great Ape Cognition Across Time and Domains: Stability, Structure, and Predictability
