Chimps Can Change Their Minds. Why Can’t We?

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HHumans are not always the rational creatures we like to think they are. If a belief makes us feel good, we often cling to it, even in the face of evidence to the contrary. Sometimes we even find a way to present new information in a way that supports that belief rather than changing our mind. Just watch any episode of Seinfeld: This human weakness is one of the main drivers of comic relief.

But the ability to change one’s mind may be more widespread in the animal kingdom than previously thought. Even chimpanzees, our closest relatives, can do it, according to a new study published in Comparative cognition. Researchers from the United States, Europe and Uganda tested whether chimpanzees were able to evaluate different types of evidence about where they would find a piece of food. What they found was that the chimpanzees could rationally weigh new and old evidence and modify their hypotheses. In that case, perhaps humans should take a cue from their cousins.

Thinking and revising one’s beliefs are forms of metacognition – thinking about thinking – and whether other animals can do this without language is a long-standing debate. It’s a question that dates back at least to Charles Darwin, who in his revolutionary speech The descendants of man warned that for the theory of evolution to hold, non-human apes would have to possess some forms of intelligence.

Read more: »Reason will not save us»

In a series of five experiments, the scientists behind the new paper presented pieces of food to groups of 15 to 23 chimpanzees living in Uganda’s Ngamba Island Chimpanzee Sanctuary, then hid the food in different locations in identical containers. The chimpanzees were given sequential cues about where this food was hidden (some stronger than others) and prompted to make choices. For example, in the first experiment, actually seeing food in a container was considered strong, while hearing food shaking in a container was weak. Once the chimpanzees made their first choice, they were presented with new evidence (weak or strong, new or redundant) and were allowed to revise their choice or stick with the initial decision.

They found that the chimpanzees made rational choices two to three times more often than non-rational choices in all treat-seeking scenarios. The results show that chimpanzees tended to evaluate the quality of evidence, were sensitive not only to the type but also the quantity of evidence, and were able to learn to avoid misleading evidence. “The chimpanzees did not assign a fixed value to each type of evidence; rather, they assessed the relative strength of the evidence,” the authors write.

Are these chimpanzees more rational than George Costanza? Most likely. If nothing else, the results serve as a reminder that changing your mind may not be so difficult.

More than Nautilus about chimpanzee cognition:

“Chimpanzees and the Zen of waterfalls”

“Empathy, morality, community, culture: chimpanzees have it all” Primatologist Frans de Waal opposes human exceptionalism.

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Main image: KensCanning / Shutterstock

• Kristen French

  Published on November 4, 2025

  Kristen French is an associate editor at Nautilus. She has worked in science journalism since 2013, reporting and writing articles and news for publications such as Wired, Backchannel, The Verge, And New York Review. She holds a master’s degree in science journalism from Columbia University.