Rhaina Cohen

Many Americans find it adequate to represent their love and devotion to one person in a single ring on their left hand.

Author Briallen Hopper would need to enlist far more metal to represent her commitments. She would have to wear stacks of rings on each finger or a clanging forearm's worth of bracelets to signify each close friend, sibling, godchild, student, author, fictional character, and sentimentally-imbued object that receives her time and support.

Bababababa, dadadadada, ahgagaga. Got that?

Babies are speaking to us all the time, but most of us have no clue what they're saying. To us non-babies, it all sounds like charming, mysterious, gobbledegook. To researchers, though, babbling is knowable, predictable, and best of all, teachable. This week, we'll find out how to decipher the vocabulary, and the behavior, of the newest members of the human family.

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STEVE INSKEEP, HOST:

Companies buy back their stock from shareholders when they have excess cash lying around, and they want to hand some of it over to the owners. And they've been doing it a lot more recently: companies are on track to spend more than a trillion dollars on buybacks this year. Today on the Indicator, dueling opinions on buybacks. One economist says they're a way to get cash to companies that need it; another argues they're a brake on the economy.

Music: "Break Me"

In a way, all of us are time travelers. If we just pause and close our eyes we can wander back to our first kiss...our first breakup...that grandparent we should have visited...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?

When Paul Kugelman was a kid, he had no shortage of friends. But as he grew older and entered middle age, his social world narrowed.

"It was a very lonely time. I did go to work and I did have interactions at work, and I cherished those," he says. "But you know, at the end of the day it was just me."

Kugelman's story isn't unusual: researchers say it can be difficult for men to hold on to friendships as they age. And the problem may begin in adolescence.

Women in the Middle Ages were excluded from many realms: the law,

We take it for granted that nostalgia is an ordinary, harmless emotion. You won't get a referral for a psychologist because you've posted a childhood photo with the caption #ThrowbackThursday, or because you have a weak spot for Lucky Charms or Fruit Roll-Ups. But that's a relatively new way of thinking.

The scientist who coined the term "nostalgia" in 1688 thought of this emotion as a neurological illness caused by demons. Other scientists latched onto this conception of nostalgia as a disease. It took marketers, centuries later, to realize that nostalgia has benefits.

Olutosin Oduwole was in his dorm room at Southern Illinois University when police knocked on his door one day in 2007. They were there to arrest him.

"In my mind I'm thinking, 'Okay, maybe a warrant for a ticket.' I really didn't know what was going on," he says.

What was going on was that the police suspected that Olutosin, a college student and aspiring rapper, was on the brink of committing a Virginia Tech-style mass shooting on his campus. He was soon charged with attempting to make a terrorist threat, and was eventually convicted and sent to prison.