The conditional emotional response as a model of Pavlovian conditioning

Many investigators have assumed that the conditional emotional response (CER) with its attendant response measure, response suppression, can be used as a model for Pavlovian conditioning; that is, that the experimental results obtained with the CER will yield findings similar to those obtained with the direct conditional stimulus (CS)-conditional response (CR) paradigm, e.g., conditioning of the eyeblink, electrodermal (EDR), finger withdrawal, etc. Several problems, however, have emerged with this assumption. The first is a methodologic-statistical one. Measurement of response suppression using the familiar ratio measure assumes that different base rates of responding should play no role in determining the size of the suppression ratio, and operant responding from one pre-CS period to another will remain stable. These assumptions have been found to be in error. In addition, the statistical assumptions of normally distributed data and homogeneous variances of the experimental and control groups also have been called to question. Some experimenters, however, have taken the position that if CER and direct CS-CR experimental findings are in general agreement when a particular conditioning variable has been manipulated, the methodologic-statistical problems that we have identified can be ignored. The experimental evidence suggests that although such comparisons frequently indicate an identity of findings, there are sufficient exceptions in which caution is urged in assuming that the two paradigms are measuring the same learning correlate.