Electrodermal responses and subjective estimates of UCS probability in a long interstimulus interval conditioning paradigm.

Abstract

ABSTRACTIn an investigation of the relationship between subjective awareness and classical conditioning, two groups of 20 subjects each were required to state subjective estimates of shock‐UCS probabilities for 5 visual CSs differing in geometrical form and signalling objective UCS probabilities of 0, 25, 50, 75, or 100%. First‐and second‐interval anticipatory and third‐interval unconditioned and omission skin conductance responses (FARs, SARs, TURs, and TORs) were measured. One group was required to learn the different CS‐UCS contingencies, and the other was instructed about the contingencies by having the objective probability superimposed on the geometrical form. The instruction group showed over‐all steeper probability gradients for subjective expectancies and FARs, whereas SARs and TORs tended to show inverted‐U shaped relationships to probability. The TUR showed no effect of probability. The trial‐by‐trial correlations between subjective expectancy and skin conductance responses were generally significant, and for the FAR they were larger in the instruction than in the learning group. The magnitude of correlation, however, was quite low. Differentiation between the 0 and 100% CSs in subjective expectancy and FARs coincided temporally.