Human behavior can be common, unusual, acceptable, or unacceptable. Behavior can be conscious or unconscious, overt or covert, and voluntary or involuntary. In sociology, behavior is considered to be the most basic human action. Behavior should not be mistaken with social behavior, as social behavior is behavior specifically directed at other people. The acceptability of behavior is evaluated relative to social norms and regulated by various means of social control. The behavior of people is studied by the academic disciplines of psychology, sociology, economics, and anthropology.