Anthropologist Margaret Mead said monogamy is the most difficult of marital arrangements. We'll look at how studies of “infidelity” in the animal world might give us insight into why humans stray. Laura’s guests are zoologist David Barash, Ph.D, and his wife Judith Eve Lipton, M.D. a psychiatrist. Together they've written a new book, "The Myth of Monogamy: Fidelity and Infidelity in Animals and People." Parental discretion advised.(Rebroadcast)