Abstract:
In classical aversive conditioning,.responses to the noxious stimulus tend to decline in magnitude over trials (Grings, i960; Hilgard, 1933; H.D. Kimmel, 1966). Responses to the stimulus which precedes the noxious stimulus initially increase in magnitude, then attenuate (Meryman, 1953; Kimmel, 1959). If the noxious stimulus is subsequently presented in absence of the preceding signal stimulus, response magnitude immediately increases (Kimble and Dufort, 1956; H.D.Kimmel, 1966). Two major attempts to explain these effects may be loosely termed the associative and the cognitive hypotheses.
The associative hypothesis has been developed from Pavlov's theory of classical conditioning (Pavlov, 1927). Accordingly, classical conditioning terminology will be used in discussion. Under this hypothesis, attenuation of the conditioned response (CR) and of the unconditioned response (UCR) is attributed to conditioned inhibition which accrues to the conditioned stimulus (CS) as a result of repeated pairing with the unconditioned stimulus (UCS). The increase in UCR magnitude when the UCS is subsequently presented alone is attributed to the release of the response from inhibition (H.D. Kimmel, 1966; M.E.Kimmel, 1967).
