The fact that chimpanzees are extremely intelligent should no longer surprise anyone. Most people also know that they have their own social cues and are very sensitive to them, but even so, they usually refuse to conform to what the majority of group members are doing, preferring to stick with their personal preferences. However, now, a new study has shown that they do change their strategy when they can obtain greater rewards.

© Max Planck Institute for Psycholinguistics

Chimps are curious by nature, showing a rich palette of interests, both intellectually and socially. But they are also rather hesitant to abandon their personal preferences, even when it becomes ineffective; many researchers suggested that they are slaves to routine, doing the same things over and over again almost mindlessly, regardless of the results. But Edwin van Leeuwen from the Max Planck Institutes for Psycholinguistics and Evolutionary Anthropology conducted a series of experiments in Germany and Zambia to see under what circumstances the chimps are willing to change their behaviors.

The researchers studied 16 captive chimpanzees at the Wolfgang Kohler Primate Research Center in Germany (Leipzig) and 12 semi-wild chimpanzees at the Chimfunshi Wildlife Orphanage Trust, a sanctuary that houses more than a hundred chimpanzees under nearly natural conditions in the north-western part of Zambia. The chimps were trained to operate two different vending machines. A minority of the group was made familiar with one machine and the majority of group members with the other machine. Basically, wooden balls were thrown into their living space. The chimps could insert the ball in the vending machines and they got a nut in exchange.

Then, the team wanted to see if the chimpanzees in the minority group would change their behaviour toward using the vending machine that the majority used. The benefits the two machines provided were identical, so they wanted to see if the minority would cave to the social majority pressure; they didn’t.

Peanuts over popularity

But in the second experiment, they changed the way the vending machines worked – so the one that the minority used now gave 5 nuts instead of one. Over time, most of the chimps switched to using the minority one, showing that they recognized the advantage and showed rationality, not conformism.

“Where chimpanzees do not readily change their behaviour under majority influences, they do change their behaviour when they can maximise their payoffs,” Van Leeuwen says. “We conclude that chimpanzees may prefer persevering in successful and familiar strategies over adopting the equally effective strategy of the majority, but that chimpanzees find sufficient incentive in changing their behaviour when they can obtain higher rewards somewhere else.” “So, it’s peanuts over popularity” he jokingly adds.

Via Max Planck Institutes for Psycholinguistics and Evolutionary Anthropology.

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