Watch VoirFilms. For how long have we been laughing? Are human beings the only ones to laugh? In the past, scientists tended to neglect such questions of laughter, leaving them to the philosophers. Jacques Mitsch's A NATURAL HISTORY OF LAUGHTER explores recent scientific attempts to explicate this most elusive of human faculties, undertaken by scientists who see it as a means of approaching some of the larger mysteries of neurology and human behavior.