Stimulus miscuing and dishabituation: electrodermal activity and resource allocation

The present research investigated the effects of miscuing a shock stimulus on dishabituation of the skin conductance response and on the allocation of processing resources. In both experiments, a control group received 21 S1-S2 pairings intermixed with 23 S3-alone presentations. For the experimental group, S2 was miscued on trials 11 and 22 by its presentation following S3. In Experiment 1 (N = 48), S2 was a shock that was either "clearly discernible" or "uncomfortable but not painful". The results indicated increased electrodermal responding when S2 was miscued by S3 and subsequent dishabituation when S2 again followed S1 on the next trial. Miscuing produced dishabituation with both a high- and low-shock S2. A continuous measure of S2 expectancy revealed that expectancy of S2 in the presence of S1 declined as a result of miscuing. Experiment 2 (N = 36) employed reaction time to a white noise probe stimulus as the dependent variable. The critical data came from probes presented 300 ms following S2 onset on the S1-S2 trial immediately following miscuing. They indicated that miscuing produced slowed reaction time to probes presented during S2 on the following S1-S2 trial. Thus, the miscuing of S2 by S3 appears to result in an increase in processing resources devoted to S2, even when S2 is presented in its usual position following S1. The results are discussed in terms of current theories of associative learning.