Research on the biology of parent-child attachment has yielded intriguing findings–for example, the complex role that the hormone oxytocin plays in activating feelings of trust and emotional commitment. The winter 2011 Parents & Science program featured Thomas R. Insel, a leading behavioral neurobiologist who heads the National Institute of Mental Health, and Myron Hofer, a psychobiologist who has pioneered the study of the infant-mother relationship and its long-term impact.