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It’s a good week to be reminded of this: According to the bulk of the scientific evidence, most people are naturally kind. Over the years, study after study has concluded that selflessness is intuitive, and that when people are pressed to make snap-judgement decisions, they typically choose to be generous instead of selfish. Overthinking, on the other hand, is what tends to lead to egocentric behavior.

As Matthew Hutson explains in a thorough analysis of the literature for Nautilus, a typical study setup looks like this:

Groups of four people, either American college students or American adults participating online, were given some money. They were allowed to place some of it into a pool, which was then multiplied and distributed evenly. A participant could maximize his or her income by contributing nothing and just sharing in the gains, but people usually gave something. Despite the temptation to be selfish, most people showed selflessness.

What’s more, further tests of this finding have revealed that when people are in a time crunch, they tend to act with greater generosity. And the opposite is true, too: When given time to think it over, people tend to choose the option that serves themselves over the one that would best serve others. “Most people think we are intuitively selfish,” Yale psychologist David Rand told Nautilus, “[but] our lab experiments show that making people rely more on intuition increases cooperation.”

These studies echo the findings of one fascinating 2014 report, in which Rand and a colleague analyzed interviews with 51 winners of the Carnegie Hero Medal. Over and over, these everyday heroes told interviewers that they’d acted on instinct. Kermit Kubitz, for example, was a 60-year-old man who fought another man who had stabbed a 15-year-old girl in a bakery. “I had only two thoughts: One, I have to get him out of the door, and two, Oh my God, this guy could kill me, too,” said Kubitz, who ended up getting stabbed, too. “I think it was just instinct. Kind of like my tendency, that nobody in my platoon is going to get attacked without me doing something. If it were my daughter, you’d do it for me. You’d do it in an instant. And I’d do it for you.”