Effects of Repeated Pre-Testing with Conditioned Stimulus upon Extinction of the Conditioned Eyelid Response to Light

Abstract

The present experiment was designed to investigate the effects of repeated pre-testing with the conditioned stimulus (CS) upon the extinction of the conditioned eyelid response to light in human Ss. Resistance to extinction has frequently been used as a measure of strength of conditioning. It is often superior to measures of the magnitude of the CR, for these often reflect 'response strength' rather than strength of conditioning.' Resistance to extinction as a measure of the strength of an associative bond seems to break down under partial reinforcement.2 A departure from 100% reinforcement apparently introduces new factors in the learning situation, and these new factors usually prolong or delay the extinction process. Pre-testing with the CS is a common procedure in conditioning experiments. Pre-testing represents a departure from 100% reinforcement and may be expected to have special effects on extinction. Such a special effect appeared in a previous experiment where an inversion of the extinction curve was observed following a single pre-test with the CS.3 Since inversion turned out not to be statistically significant, more extended investigation of the phenomena seems to be desirable. Instead of a single pre-test in a two-day experiment, however, three pre-tests were given on the first three days of a four-day experiment, with extinction on the fourth day. Instead of using only zero and five-trial pre-tests as before, the effects of zero, five-trial, and 10-trial pre-tests were investigated.