Laughter is often called the most human sound. It carries joy, relief, connection, and sometimes even healing. For centuries, we believed that laughter belonged only to us, a special emotional ...

Human laughter may trace its evolutionary beginnings to vocalizations made during play. This type of "laughing" is found in many mammals and even in some birds.

For many years, psychologists and behavioral biologists agreed that laughter was a unique emotional expression found only in humans. However, as the study of animal emotions expanded this idea was ...