Evaluative context and conditioning effects among same and different objects.

We address an apparent discrepancy in the literature on how context stimuli influence evaluations of target stimuli. While a rich literature suggests that target evaluations are often contrasted away from the valence of context stimuli, reported effects of evaluative conditioning (EC) are almost exclusively assimilative. Specifically, when a neutral conditioned stimulus (CS) repeatedly co-occurs with a positive unconditioned stimulus (US), the CS is later evaluated more positively. Contrast effects from mere co-occurrences are absent in the EC literature. We hypothesized that this can be explained by the stimulus composition in EC tasks, which usually depict different objects as target (CS) and context (US). In 10 experiments, we confirmed that when target and context stimuli depict different objects, assimilation clearly dominates. Yet, when target and context depict stimuli from the same object class, contrast effects become dominant. These contrast effects are invisible in standard EC tasks because CSs are contrasted with all positive and negative USs of a given stimulus set. The present work thereby identifies a central determinant of the direction that evaluative context and conditioning effects take. While different-object contexts evoke assimilation, same-object contexts increase the likelihood of contrastive evaluations. We discuss the various theoretical and practical implications of our findings. (PsycInfo Database Record (c) 2023 APA, all rights reserved).