Guests: Terry Burnham and Jay Phelan.

How much of human behavior is genetically determined? We'll revisit this age-old question this morning on Focus as we talk with authors Terry Burnham and Jay Phelan. They claim that humans are well adapted to the environment in which they originated, but since we no longer live as hunter-gatherers, our basic instincts can lead to harmful behaviors. They also argue that knowing this can help us control our behavior and lead us to happier lives.