Lulu Miller

Mike Marsella was a really competitive guy, a champion cross-country runner in high school. He got a running scholarship to college. Then a car hit him while he was riding a moped. He was left in a coma, with brain damage. And when his mind changed, his running changed, too.

Would he ever be Mike Marsella again? And would he ever run a four-minute mile?

For the past month and a half, we've been exploring the invisible forces that shape our lives in NPR's newest program, Invisibilia. Now we're ending the pilot season with a visible twist — exploring the ways computers shape our behavior, and the way we see the world.

Iggy Ignatius was born in India. Even though he moved to the States in his 20s, he still felt that India was the place he belonged. He always thought he'd retire there. But when the time approached, there was a problem.

"My daughters, my son, my grandchildren are all like chains that do not allow you to leave for India," Ignatius says.

He couldn't imagine leaving them to go to the place he belonged. He was torn. And then one day it hit him. What if he built an Indian retirement community — in Florida?

For someone who is blind, a simple click can be the sound of sight.

What would you do if you were locked in your body, your brain intact but with no way to communicate? How do you survive emotionally when you are invisible to everyone you know and love?

That's the first question asked by NPR's new program on human behavior, Invisibilia.