Tara Boyle

We just can't let go of some decisions. We replay them in our head and imagine alternate endings.

These sorts of looping mental videos are called counterfactuals. Northwestern University Professor Neal Roese says there's real value to wondering "if only."

"Counterfactual thoughts are generally useful for us in terms of providing a set of options that we might act upon in the future," he says. "This can lead to improvement. It can lead to learning from experience."

Throughout history, people have sought to create utopias. Perfect societies free of defects.

Of course, not everyone shares the same vision for a utopia. Different people have different priorities. But the wishes of those with power and prestige almost always take precedence.

On this episode of the Hidden Brain radio show, we tell the story of overzealous American scientists who believed creating a utopia for some would eventually lead to utopia for all. This is a story of people who believed they were doing the enlightened thing, even if it traumatized others.

Here's how it usually goes: You're working from home and you dial in to a conference call for the morning meeting. Everyone is cheerfully talking around the table. You can't believe what a good time everyone seems to be having, talking about nothing.

Then someone starts to laugh. And then everyone's laughing. Except for you, silently listening on the phone. You're not even cracking a smile, forget about laughing. You wonder, when did this conversation become so hilarious? What am I missing?

A while back, Jonah Berger was talking with a lawyer friend from Washington, D.C. The friend was lamenting the impact of social influence on his peers.

He was saying, "'God, you know, all D.C. lawyers are the same. They make it big, and they go out and they buy a new BMW.'

Many people start exploring their sexuality in college. The lessons they learn about intimacy and attraction during these years lay a foundation for the rest of their lives.

"I have students who have had sex many times drunk but have never held someone's hand," says Occidental University sociologist Lisa Wade.

In 2012, as a new mom, Maranda Dynda heard a story from her midwife that she couldn't get out of her head. The midwife told her that years earlier, something bad had happened after she vaccinated her son. One minute he was fine, and the next, he was autistic. It was like "the light had left his eyes," Maranda recalled her saying. The midwife implored Maranda to go online and do her own research. So she did.

She started on Google. It led her to Facebook groups, where other moms echoed what the midwife had said.

After you read this sentence, pause for a moment to think back on advertisements you first heard when you were a child.

Perhaps you recall a favorite jingle or the catchphrase of a cereal mascot. You probably can remember more than just one.

This week, we look at the shelf life of commercials. According to University of Arizona researcher Merrie Brucks, an ad we watched when we were five years old can influence our buying behavior when we're 50.

"Fake news" is a phrase that may seem specific to our particular moment and time in American history.

But Columbia University Professor Andie Tucher says fake news is deeply rooted in American journalism.

In 1690, British officials forced the first newspaper in North America to shut down after it fabricated information. Nineteenth-century newspapers often didn't agree on basic facts. In covering a lurid murder in 1836, two major papers in New York City offered wildly differing perspectives on the case.

There is great comfort in the familiar. It's one reason humans often flock to people who share the same interests, laugh at the same jokes, hold the same political views. But familiar ground may not be the best place to cultivate creativity.

Columbia Business School professor Adam Galinsky has found that people who have deep relationships with someone from another country become more creative and score higher on routine creativity tests.

Annie Duke was about to win $2 million.

It was 2004, and she was at the final hand of the World Series of Poker Tournament of Champions. Annie had beaten some of the best poker players in the world — all men — to get to this point.

But she wasn't sure she deserved to be there.

"I'm sort of thinking, if I fold and I'm wrong, everybody's going to be like, 'See, she plays like a girl, look how he pushed her around,' " said Annie.

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