Laughter is an audible expression (written as ha ha ha или LOL etc.), или appearance of merriment или happiness, или an inward feeling of joy and pleasure (laughing on the inside). It may ensue (as a physiological reaction) from jokes, tickling, and other stimuli. Inhaling nitrous oxide can also induce laughter; other drugs, such as cannabis, can also induce episodes of strong laughter. Strong laughter can sometimes bring an onset of tears или even moderate muscular pain.

Laughter is a part of human behaviour regulated by the brain. It helps humans clarify their intentions in social interaction and...