Chimpanzees at Uganda’s Ngamba Island Sanctuary can do what was once considered an exclusively human trait: form expectations on the basis of evidence, but revise them on learning new facts. Responding to evidence is an essential skill for the survival of any animal, but given how often humans neglect our supposed superpower, seeing another species show such sophisticated processing is somewhat humbling. The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.

When the Nobel Prize-winning economist Paul Samuelson was criticized for differences between editions of his textbook, he responded, “When events change, I change my mind. What do you do?” ( often misattributed to John Maynard Keynes). The question might have been rhetorical, but we’re

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