The associative factor in eyelid conditioning.

Abstract

The two experiments reported in this paper studied the development of the associative process in eyelid conditioning. The technique was that of giving initial training in trials where the CS (a dim light) and the UCS (an air puff) were paired, and then presenting the UCS alone for a series of trials. The strength of conditioning was measured in extinction in Exp. 1, and in a series of further conditioning trials in Exp. n. In Exp. I, five groups of 6 Ss each received 3,5,10,20 or 30 conditioning trials, 35 UCS trials, and 30 extinction trials. Resistance to extinction was found to increase with the number of initial conditioning trials up to 20. A more detailed analysis indicated that the number of CRs in the initial trials was the important determiner of resistance to extinction. In Exp. n, 6 different groups of Ss received trials in which the CS and UCS were paired until they produced 0,1,2,3,5, or 10 CRs, followed by 20 air-puff trials to bring the total to 60, and 30 extinction trials. The 0-CR group received the 20 air-puff trials before 60 CS-UCS trials and 30 extinction trials. A seventh, control, group received 60 CS-UCS trials and 30 extinction trials without any UCS trials. A comparison of this latter group with the 0-CR group showed that, under these circumstances, the UCS trials interfere with conditioning. For all other groups, the UCS trials were facilitating. Performance in the first 10 trials after the UCS trials increased with the number of previous CRs up to a limit reached with the occurrence of 3 CRs. The results are treated as supporting an S-R view of classical conditioning.