In 1963, John Stacey Adams put forth an "equity theory" of this phenomenon, which focuses on creating a balance between inputs and outputs. Philip Zimbardo's book on the "cognitive control" of this factor, discusses consequences of choice and dissonance. A formula that includes valence and instrumentality is known as Victor Vroom's expectancy theory of this trait. Another 
In 1963, John Stacey Adams put forth an "equity theory" of this phenomenon, which focuses on creating a balance between inputs and outputs. Philip Zimbardo's book on the "cognitive control" of this factor, discusses consequences of choice and dissonance. A formula that includes valence and instrumentality is known as Victor Vroom's expectancy theory of this trait. Another theory states that "hygiene factors" will not increase this value, but can decrease it if they are absent, unlike "intrinsic factors" - that is Frederick Herzberg's two-factor theory of this trait. Clark Hull posited that it arises in humans as a result of tension or arousal caused by unfulfilled biological needs; that is known as the "drive reduction theory" of this quality. Its "deficiency" or "D" type is said to occur when one must satisfy a need, according to Abraham Maslow's book about it "and personality." For 10 points, name this impetus that pushes a person toward completing a task.