Human eyeblink classical conditioning: Effects of manipulating awareness of the stimulus contingencies

In four groups, we either promoted or prevented a,awareness of the stimulus contingencies during trace or delay differential eyeblink classical conditioning. To reduce awareness of the stimulus contingencies, we asked two groups to engage in a secondary attention-demanding task during trace or delay conditioning. To promote awareness of the stimulus contingencies, we explained the relationships bent een the stimuli to two other groups before trace conditioning. One of these groups then engaged in the secondary task during conditioning. Following conditioning, awareness of the stimulus contingencies was assessed with a true/false questionnaire. Preventing awareness of the stimulus contingencies disrupted trace differential eyeblink conditioning but did not affect delay differential conditioning. Providing knowledge about the stimulus contingencies facilitated trace conditioning. Finally, providing knowledge about the stimulus contingencies, then having subjects engage in a distraction task disrupted trace conditioning. Results are discussed in terms of the role of declarative and nondeclarative memory systems during trace eyeblink conditioning.