Ted Radio Hour: Hardwired

: How much of who we are is biology? How much is learned? And how much can we change? In this week's show, TED speakers on how genes and experience collaborate -- and compete -- to make us who we are.

Neuroscientist Robert Sapolsky says nearly all aspects of human behavior are explained by biology: from developments millions of years in the past to microscopic reactions happening in the present.

Many think genetic makeup is fixed from the moment we're born. But Moshe Szyf  says this understanding is incomplete because our experiences and environment have the power to change our basic biology.

Are you introverted or extroverted? It depends. When it comes to personality traits, Brian Little says we can actually act against our biology -- especially if we pursue a "core life project."