Why Humans Like to Cry

Human beings are the only species to have evolved the trait of emotional crying. We weep at tragedies in our lives and in those of others - remarkably even when they are fictional characters in film, opera, music, novels, and theatre. Why have we developed art forms - most powerfully, music - which move us to sadness and tears? This question forms the backdrop to Michael Trimble's discussion of emotional crying, its physiology, and its evolutionary implications.