A BEHAVIORAL PREPARATION FOR THE STUDY OF HUMAN PAVLOVIAN CONDITIONING

Conditioned suppression is a useful technique for assessing whether su bjects have learned a CS-US association, but it is difficult to use in humans because of the need for an aversive US. The purpose of this re search was to develop a non-aversive procedure that would produce supp ression. Subjects learned to press the space bar of a computer as part of a video game, but they had to stop pressing whenever a visual US a ppeared, or they would lose points. In Experiment 1, we used an A+/B- discrimination design: The US always followed Stimulus A and never fol lowed Stimulus B. Although no information about the existence of CSs w as given to the subjects, suppression ratio results showed a discrimin ation learning curve-that is, subjects learned to suppress responding in anticipation of the US when Stimulus A was present but not during t he presentations of Stimulus B. Experiment 2 explored the potential of this preparation by using two different instruction sets and assessin g post-experimental judgements of CS A and CS B in addition to suppres sion ratios. The results of these experiments suggest that conditioned suppression can be reliably and conveniently used in the human labora tory, providing a bridge between experiments on animal conditioning an d experiments on human judgements of causality.