an increase of activation followed by a sudden decrease, often accompanied by laughter to signify a release of tension. The abrupt drop from elevated levels of arousal to a lower, more appropriate level of arousal is thought to produce a pleasurable response, which is what causes the laughing. Common experiences that can produce this response include a rollercoaster ride. [introduced in 1970 by British-born Canadian psychologist Daniel E. Berlyne (1924-1976))