This study tried to assess the effects of instructions on conditioned alpha blocking. To do this, an equal number of college students were first assigned to an informed group (lG) or an uninformed group (UIG) and administered the same number and sequence of pseudoconditioning, conditioning, and extinction trials, using one of three different light intensities. The reinforcing property of a light US was also assessed by measuring UR magnitude in pseudoconditioning for individual subjects; the college students were later grouped with respect to the presence of low or high URs. It was found that UR magnitude, not US intensity, was predictive of conditioned alpha blocking. Nonetheless, conditioned alpha blocking occurred only for the subjects in the UIG who had low URs. For this group, conditioI1ed alpha blocking was manifested as an increased effectiveness of the CS in blocking the alpha rhythm following a series of paired CS-US trials, and longer latencies of the alpha CR in conditioning and extinction as compared with the OR-produced responses in pseudoconditioning. The use of UR magnitUde as a measure of the effectiveness of the US in producing conditioned alpha blocking and the effects of instructions on the conditionability of the EEG response system are discussed.Following an early report by Cook and Harris (1937) showing that instructions can be as effective as paired CS-US trials in producing a GSR, there has been a revived interest in examining the role of instructions in classical conditioning (Dawson & Furedy, 1976 found that for the GSR response system, instructions influenced the magnitude of the UR, and it was through this link that CR efficacy may have been altered. Maltzman, Gould, Pendery, and Wolff (1977) reported that UR magnitude was an accurate predictor of CRs for a semantic conditioning study using the GSR response system. These investigators found better semantic conditioning in subjects showing effective UR magnitudes that were measured before the start of the conditioning trials. In a recently completed study, Braggio and Putney (1980) reported thatJor the EEG response system subjects with low UR magnitudes in pseudoconditioning demonstrated conditioned alpha blocking, while those with high UR magnitudes did not. These results suggest that the reinforcing effects of a given US may depend on one or more subject-defined factors of physiological activation that can be tapped by the UR magnitude factor prior to the start of the conditioning trials (Braggio & Putney, 1980). The purpose of the present experiment was to determine if the conditionability of the EEG response system was influenced by instructions and light intensity; and, if so, were the effect(s) mediated by the UR magnitude variable?
METHODSubjects From a presample of 34 college students, a total of 24 undergraduates with a median age of 22.4 years (range 18-28) were 0090-5046/80/030398-07$00.95/0