Stimulus compounding in classical fear conditioning

The effect of stimulus compounding in classical conditioning was investigated by conditioning one group of rats to a compound CS consisting of a buzzer and light and then conditioning separate groups of rats to the individual elements of the compound CS. On hurdle-jump test trials, the group of Ss conditioned to the compound CS performed better than Ss conditioned to the elements of the compound. Strength of conditioning to each of the elements of the compound CS was about equal. There was some evidence of a summation effect resulting from conditioning to the compound CS. Strength of conditioning to the compound CS was somewhat greater than the sum of the response strengths conditioned to the elements of the compound CS.