significant or more rewarding the incentive, the more the individual is willing to do to get to the end of a task. This is one of the reasons that college students will go on to graduate school. The students may be worn out, but they are willing to go through more school for the reward of getting a higher paying job when they are out of school. Reversal Theory Reversal theory, first introduced by Dr. Michael Apter and Dr. Ken Smith in the 1970s, is a structural, phenomenological explanation of psychological states and their dynamic interplay. The theory contributes to an understanding of emotions and personality in which endogenous (cognitive) and exogenous (environmental) implications are considered. The theory proposes eight meta-motivational states arranged into four pairs that drive and respond to all human experience. When a state is interrupted or satiated, one "reverses" to the other state in the pair (domain). Unlike many theories related to personality, reversal theory proposes that human behavior is better understood by studying dynamic states than by the average of behavior over time trait theory. Another distinction of reversal theory is its direct contrast with the Hebbian version of the Yerkes–Dodson law of arousal, which can be found in many forms of psychotherapy. Optimal arousal theory proposes that the most comfortable or desirable arousal level is not too high or too low. Reversal theory proposes in its principle of bistability that any level of arousal or stimulation may be found either desirable or undesirable depending on the meta-motivational state one is in. Reversal theory has been academically supported and put to practical use in more than 30 fields (e.g., sports psychology, business, medical care, addiction, and stress) and in over 30 countries. Sources McGregor, D. (1960). The human side of enterprise. New York, 21. Notes References Motivational theories