Eyelid conditioning and intellectual level: effects of repeated acquisition and extinction.

Groups of college students and moderately retarded persons averaging approximately equal age received eight alternating phases of acquisition and extinction trials with an electric pulse as the unconditioned stimulus for classical eyelid conditioning. The two conditioning groups did not differ significantly in attaining the acquisition criterion during any phase and showed systematic improvement in approaching the maximal rate of acquisition. However, the college students exhibited abrupt extinction in every phase, in contrast to retarded subjects. "Learning to learn" in the retarded group was more marked across acquisition than across extinction phases. Random control groups of the two subject classes displayed equal relative frequencies of nonconditioned blinks. Some of the findings clearly contradict a stimulus-context hypothesis of differences in learning rate associated with IQ level.