What makes us the people we are? For thousands of years, the "nature versus nurture" debate has raged on. We'll see how we can actually measure the effects of heritability and environment, and begin to address how our genes interact with experience to produce mind, brain and behavior. We'll look at cool studies comparing identical and fraternal twins, talk about the evolution of human cognition, ask what innateness and heritability really mean, and discuss the philosophical questions that these issues bring up.