The great apes too seem human in making sophisticated decisions, based on what they know and the likelihood of success when guessing, according to a German study.
The study, led by Daniel Haun of the Max Planck Institutes for Psycholinguistics (Nijmegen) and Evolutionary Anthropology (Leipzig), investigated the behaviour of all four great ape species, comprising chimps, orangutans, gorillas and bonobos.
The apes were presented with two banana pieces: a smaller one, which was always reliably in the same place, and a larger one, which was hidden under one of the multiple cups, and therefore the riskier choice.
The researchers found that the apes’ choices were regulated by their uncertainty and the probability of success for the risky choice, suggesting sophisticated decision-making.
The apes chose the small piece more often when they where uncertain where the large piece was hidden. The lower their chances to guess correctly, the more often they chose the small piece.
Researchers also found that the apes went for the larger piece – and risked getting nothing at all – no less than 50 percent of the time.
This risky decision-making increased to nearly 100 percent when the size difference between the two banana pieces was largest.
While all four species of species demonstrated sophisticated decision-making strategies, chimpanzees and orangutans were overall more likely to make risky choices relative to gorillas and bonobos.
Haun concludes: “Our study adds to the growing evidence that the mental life of the other great apes is much more sophisticated than is often assumed.”
The findings may provide an insight into human decision-making as well.