Alan Alda, talks about hosting—and participating in experiments for—the three-part PBS series "The Human Spark." It looks into the question "what makes us human," from anthropological, social, and scientific viewpoints.

In addition to serving as the host, Alda also participates in experiments, including one on his brain. "The Human Spark" is airing on PBS January 6, 13, and 20, at 8:00 pm.