Human evaluative conditioning: acquisition trials, presentation schedule, evaluative style and contingency awareness

Verbal evaluative conditioning with undetected US presentations

In evaluative conditioning research it has been shown that a neutral stimulus (CS) acquires the valence of a positive or negative stimulus (US) with which it is presented contingently. An experiment is reported in which it is examined whether evaluative shifts can also be observed in the complete absence of contingency-awareness. Neutral words were either followed by a briefly presented positive or negative word. Results showed that neutral words which were presented contingently with a positive word, were afterwards liked more than words which were paired with negative words. This result was obtained despite the fact that Ss were not aware of the presentation of the briefly presented USs.

Is evaluative conditioning a qualitatively distinct form of classical conditioning?

This paper contains a critical review of the claim that evaluative conditioning (EC) represents a theoretically distinct form of classical conditioning. A review of the evidence suggests that: (i) while it is claimed that EC can occur without awareness, EC studies have either adopted inappropriate statistical comparisons to demonstrate this or have failed to use the control conditions necessary to indicate that what is being measured is associative conditioning; (ii) there is no theoretical reason why conditioning without awareness might be observed in any conditioning paradigm if a relatively complex covariation assessment procedure such as that adopted in EC studies is used; and (iii) there are a variety of possible explanations for the relative resistance to extinction reported with EC, some of which allude to failure to use appropriate control conditions and others which point to specific details unique to the EC extinction procedure. Until these appropriate procedural and statistical comparisons are made, it is concluded that it is premature to assume that EC represents a form of conditioning that is theoretically distinct from other types of classical conditioning.

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.