Alix Spiegel

This week, the podcast and show Invisibilia examines the nature of reality, with a Silicon Valley techie who created apps to randomize his life, a psychologist who trains herself to experience the world like dogs do and

Welcome to Invisibilia Season 3! The NPR program and podcast explores the invisible forces that shape human behavior, and we here at Shots are joining in to probe the often tenuous line between perception and reality. Here's an excerpt from Episode 1.

Editor's note: This is an excerpt from the latest episode of the Invisibilia podcast and program, which is broadcast on participating public radio stations.

Until she was 54 years old, Kim was totally unaware that there were things in the world she couldn't see.

"This was the whole problem," Kim says. "I had no clue what the problem was."