Rhaina Cohen

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?

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.