ESTES and SKI~]~ (1941) reported an experimental procedure to develop a state of anxiety in the experimental animal and to monitor the effects of this anxiety on the "normal behavior of the organism", (p. 391). B~ADY and Hu~T (1955) have formalized the procedure and studied it extensively as the "conditioned emotional response (CER)". "The phenomena is referred to as a 'response' because overt reactions are used as indicators ; it is referred to as 'emotional' because these overt reactions develop as a consequence of reinforcement with a mildly painful electric shock and because of the character of the reaction; and it is called 'conditioned' because the experimental procedure brings these reactions under the control of an ordinarily neutral stimulus (p. 314)." The phrase conditioned suppression has been suggested for this paradigm and will be followed here since it connotes little beyond what is observed: the cessation of ongoing behavior.
In this procedure a neutral stimulus is paired with negative reinforcement (shock to the feet). This stimulus-shock sequence is typically superimposed on operant responding for positive reinforcement. The rate of responding during the stimulus decreases considerably from the rate maintained in the absence of the stimulus. This decreased rate of responding during the stimulus possibly occurs because the response elicited by the stimulus --as a result of the pairings with the shock --interfere with the ongoing operant responses.
Because the disruption of motivated behavior during the stimulus occurs as a result of previous learning, and not as a result of the presence of the shock, the procedure has been seen as one satisfactory for the screening of ataraxics (KI~A~D et al. 1962). B~ADY (1956) has reported that reserpine, given chronically, increases responding during the shock paired stimulus, u Kt~A~D ct al. (1962) administered reserpine thirty minutes before testing and failed to find any attenuation of the behavior suppression during the stimulus period. These investigators also reported that chlorpromazine did not increase responding during the shock paired stimulus.