Where does our individuality come from?

We all have characteristics unique to ourselves, from our intelligence and sexual orientation to our height, weight and food preferences. Where do these traits come from? Are we genetically pre-programmed? What can we learn from studying twins? Why do they display so many similar characteristics even when raised apart? Beyond hereditary and experience, is there also something else in the mix that makes us who we are?  

KCRW's Life Examined is a one-hour weekly show exploring science, philosophy, faith — and finding meaning in the modern world. The show is hosted by Jonathan Bastian. Please tune in Sundays at 9 a.m., or find it as a podcast.