Shankar Vedantam

All of us are time travelers. If we just pause and close our eyes we can wander back to our first kiss, or the summer that went on forever. This week, we explore two emotions that pull us into the past: regret and nostalgia. How can we make these feelings work for us, and what can we learn from them?

After a disaster happens, we want to know, could something have been done to avoid it? Did anyone see this coming?

Many times, the answer is yes. There was a person — or many people — who spotted a looming crisis and tried to warn those in power. So why didn't the warnings lead to action?

Many people think of the economy as following a set of fairly scientific principles.

We buy more if things are cheap. We buy less if they're expensive. Companies hire more people if it looks like the economy is growing. They cut back if it looks like things are going to tank. Or say you're in charge of the Federal Reserve. Economic indicators help decide whether to raise or lower interest rates.

All of this seems very rational, very mathematical.

Writers and filmmakers hoping to hoodwink their fans with plot twists have long known what cognitive scientists know: All of us have blind spots in the way we assess the world. We get distracted. We forget how we know things. We see patterns that aren't there. Because these blind spots are wired into the brain, they act in ways that are predictable — so predictable that storytellers from Sophocles to M. Night Shyamalan have used them to lead us astray.

NOEL KING, HOST:

This is one of those debates that has been going on for a long time. Does being part of an organized religion improve your mental health? The host of NPR's Hidden Brain, Shankar Vedantam, joins us to share some new research on this subject. Hey, Shankar.

SHANKAR VEDANTAM, BYLINE: Hey, Noel.

KING: So I feel like I've read reports before that say if you're religious, it does benefit your mental health in some ways.

Why do you work? Popular wisdom says your answer depends on what your job is.

But psychologist Amy Wrzesniewski at Yale University finds it may have more to do with how we think about our work.

"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.

RACHEL MARTIN, HOST:

Some time ago, a couple of psychologists were having lunch together at a cafe in Harvard Square in Cambridge, Mass. They did what millions of us do as we chat with other people. They put down their smartphones on the table next to them. The host of NPR's Hidden Brain podcast Shankar Vedantam is here to explain what happened next. Shankar, welcome.

SHANKAR VEDANTAM, BYLINE: Hi, Rachel.

MARTIN: I am dying with suspense.

VEDANTAM: (Laughter).

MARTIN: Tell me what happened. Did the phones start ringing?

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."

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?

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.

In 2006, Derek Amato suffered a major concussion from diving into a shallow swimming pool. When he woke up in the hospital, he was different. He discovered he was really good a playing piano.

Paul Rozin has been studying the psychology and culture of food for more than 40 years. And he's come to appreciate that food fills many of our needs, but hunger is just one.

"Food is not just nutrition that goes in your mouth or even pleasant sensations that go with it," he says. "It connects to your whole life, and it's really a very important part of performing your culture and experiencing your culture."