any stimulus or inhibitory reaction that decreases the degree of arousal of an individual after it has reached an uncomfortably high level. According to Daniel E. Berlyne, a sharp increase in arousal can have unpleasant or aversive effects, but an arousal-reduction mechanism can produce positive hedonic value by lowering the arousal curve. The mechanism may have a natural inhibitory effect on central nervous system circuits, or it may result from a stimulus that conveys a sense of harmony or concinnity. Compare arousal-boost mechanism.