Behav. Res. Ther. Vol. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA 30,No. 2, pp. 133-142, 1992 Printed in GreatBritain. All rights reserved 0005-7967/92 $5.00 + 0.00 Copyright 0 1992 Pergamon Press plc HUMAN EVALUATIVE CONDITIONING: ACQUISITION TRIALS, PRESENTATION SCHEDULE, EVALUATIVE STYLE AND CONTINGENCY AWARENESS FRANK BAFwNs,*t PAUL EELEN, GEERT CROMBEZ and OMIZR VAN DEN BERGH Department of Psychology, University of Leuven, Tiensestraat 102, B-3000 Leuven, Belgium (Received 6 July 1991) Summary-Two different processes may be operative in human Pavlovian conditioning: signal learning and evaluative learning. Whereas most studies on evaluative conditioning focused on a mere demon- stration of the phenomenon or on a theoretical analysis of the underlying processes, some basic parameters of evaluative learning are still unexplored. Hence, using the standard neutral picture-(dis)liked picture pairing paradigm (Baeyens, Eelen & Van den Bergh, 1990) in this study the effect of two parameters of evaluative conditioning was assessed on a between-subjects base, namely the Number of Acquisition Trials (2/S/10/20) and the Presentation Schedule of the stimulus pairs (blockwise or random). Additionally, the study included an exploratory analysis of the potential effects of the Evaluative Style of subjects (Feelers vs Thinkers, operationalized in terms of speed of emitting evaluations). Finally, the relationship between contingency awareness and evaluative learning was reassessed. Neutral-liked conditioning was found to be quadratically related to the number of acquisition trials (increase in effect up to 10 trials, decrease from 10 to 20 trials), whereas neutral-disliked conditioning linearly increased with increasing numbers of trials. Randomized vs blockwise presentation schedules of the stimulus pairs did differentially affect the overall pattern of conditioning, but in a way which was both unexpected and difficult to account for theoretically. Both the Evaluative Style of subjects and contingency awareness were demonstrated to be generally orthogonal to conditioned shifts in CS valence. Based on these findings, some practical suggestions are provided for the application of evaluating conditioning based therapeutical interventions to affective- behavioral disorders which are centred around inappropriate (dis)likes. In the standard human evaluative conditioning experiment it can be demonstrated that the mere paired presentation of a subjectively neutral (N) stimulus (CS) with a subjectively liked (L) or disliked (D) stimulus (US) results in the neutral stimulus acquiring positive or negative valence [e.g. Baeyens, Eelen, Van den Bergh & Crombez (1989a, b, 1992); Martin & Levey, 1987; Stuart, Shimp & Engle, 19871. Typically, evaluative responses are measured by means of Semantic Differential or visual analog rating scales. This phenomenon has been documented in forward, backward and simultaneous conditioning preparations, using (nonverbal) CS and US of visual, auditory and gustatory-olfactory sensory modalities (Bierley, McSweeney & Vannieuwkerk, 1985; Stuart et al., 1987; Zellner, Rozin, Aron & Kulish, 1983). Although phrased in different theoretical concepts, additional evidence for evaluative conditioning is provided by the numerous language/semantic/meaning conditioning studies, originating in the Staats and Staats (1957) paradigm (for a review, see Jaanus, Defares & Zwaan, 1990). Even though the procedural similarities with human Pavlovian autonomic conditioning prep- arations are obvious, evidence is accumulating indicating that the processes and the represen- tational structure underlying evaluative conditioning are different from those involved in the prototypical tone-shock conditioning paradigm, measuring autonomic responses (heart rate or skin conductance) as indices of learning (e.g. Dawson & Shell, 1987). As argued elsewhere (Baeyens et zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA al., 1990), this last type of learning paradigm may be properly conceived of as an instance of signal-learning referring to the process by which a CS acquires the capacity to generate the expectation of a US-going-to-occur-here-and-now. This type of learning (at least in humans) depends on Ss’ awareness of the crucial CS-US relation; it is sensitive to extinction manipulations, and it is determined by the objective statistical nature of the CS-US contingency (Dawson & Shell, 1987). The separate identity of the type of learning studied in evaluative conditioning paradigms is inferred from the following findings. First, it has been demonstrated that evaluative learning does *Research Assistant of the National Fund for Scientific Research, Belgium. tAuthor for correspondence. 133