Sequential and simultaneous feature positive discriminations: Occasion setting and configural learning in human Pavlovian conditioning

Using a conditioned suppression preparation, the authors investigated seque ntial (X --> A+/A-) versus simultaneous (XA+/A-) feature positive (FP) disc rimination learning in humans. The sequential discrimination was expected t o be resolved by means of a Feature X Modulated Target A-US association and the simultaneous discrimination by a feature X-US association. After seque ntial FP training, extinction of Feature X did not affect discriminative X --> A/A responding (Experiment 1), and X transferred its modulatory ability only to new targets, B, that had also been modulated (Experiment 2). This suggests that the sequential FP discrimination indeed resulted in occasion setting. Unlike expected, Feature X Extinction did not affect discriminativ e XA/A responding after simultaneous FP training (Experiment 3), while at t he same time Feature X did show the predicted nonselective transfer to new targets, B (Experiment 4). J. M. Pearce's (1987) configural learning theory can account for most but not all findings of Experiments 3 and 4.