A new study has observed for the first time how chimpanzees can weigh different types of evidence – and change their beliefs in response to a more convincing argument.
How to test monkey minds? Apples help. Hannah Schleihauf and her colleagues designed five experiments with chimpanzees (Pan troglodytes) at the Ngamba Island Chimpanzee Sanctuary in Uganda. Each experiment involved hiding a piece of apple in a box and wait for the chimpanzee to choose a box based on the evidence presented.
“This is, in fact, the more demanding and rigorous testing to understand so-called second-order evidence,” Schleihauf told . “I believe we have evidence to affirm that rationality, in its fundamental form, is not exclusively human, but that we also share some basic processes with chimpanzees.”
“I went into this study with no expectations, because no one had done this before,” said Schleihauf, one of the authors of the published in Science this month.
“Animals don’t just act on instinct, their behavior follows a certain pattern and they actually follow the evidence in the world. Reflective responsiveness to reason means they are aware of why they hold certain beliefs. Showing that they changed their opinion when the reason was refuted is proof that they have this capacity”, he states.
New evidence appears to support the idea that intelligence alone is not what makes us human.
“I believe there are still huge differences between us, but also more similarities than we thought,” Schleihauf said.
