Behavior, Human, the reaction, or response, of a person to a given situation. Some kinds of behavior are inborn, or native —for example, the reflex of swallowing or grasping. Most, such as typing or riding a bicycle, are learned (acquired through experience or training).

Some psychologists classify reactions as follows:

  • Gross behavior—reactions that an observer can see. Examples: grasping and laughing.
  • Internal physiological activity—reactions that can be studied only by special apparatus. Example: change in blood sugar during fright.
  • Conscious experience—thinking and other activities that can be described only by the person being studied.

A variety of motives arouse or stimulate behavior. Some are physiological needs or drives, such as hunger and thirst. Other motives arise out of a person's experiences. Among such motives are his interests, goals, and attitudes, and his desire for recognition and companionship. Many forms of behavior are controlled by force of habit. A person is often unaware of the motives that lead to his own behavior. Psychiatrists trace many abnormalities of adult behavior to childhood experiences that seemingly have been forgotten.