The role of CS-US contingency in human evaluative conditioning.

Recent studies suggest that in Pavlovian conditioning, two different processes may be operative: signal learning and evaluative learning, resulting in two qualitatively different associative structures. Signal-learning is hypothesized to be responsible for providing us with genuine predictors (CS) for significant events (US). This proposition logically entails that the statistical-correlational relation, i.e. the contingency between CS and US should be a crucial determinant of signal learning. Evaluative conditioning, on the other hand, refers to the observation that the mere pairing of neutral with (dis)liked stimuli changes the valence of the originally neutral stimuli in a (negative) positive direction. As argued elsewhere, evaluative conditioning is probably based on the CS acquiring a mere referential value to the US, without any genuine CS-US expectancy being involved. From this, it was hypothesized that evaluative conditioning might not be dependent on CS-US contingency. Using the standard evaluative conditioning paradigm, four different levels of CS-US contingency were created on a between-subject base. The overall effect of evaluative conditioning was strongly significant, and was not mediated by awareness of the CS-US relation. Of crucial importance, this conditioning effect did not interact with the level of contingency, supporting the hypothesis that CS-US contingency is not a crucial determinant of evaluative conditioning. Moreover, this effect was obtained in a situation in which Ss simultaneously evidence to have consciously registered quite accurately the different levels of CS-US contingency.