Reactive inhibition is a phrase coined by Clark L. Hull in his 1943 book titled Principles of Behavior. He defined it as: Whenever any reaction is evoked in an organism there is left a condition or state which acts as a primary negative motivation in that it has an innate capacity to produce a cessation of the activity which produced the state. Hull goes on to further explain the decay of performance through the use of a decay formula which can estimate the rate of performance deterioration. Hull explains: I dissipates exponentially with time t: (Hull, 1951, p. 74).