No evaluative conditioning effects with briefly presented stimuli.

Evaluative conditioning (EC) changes the preference towards a formerly neutral stimulus (conditioned stimulus; CS), by pairing it with a valent stimulus (unconditioned stimulus; US), in the direction of the valence of the US. When the CS is presented suboptimally (i.e., too briefly to be consciously perceived), contingency awareness between CS and US can be ruled out. Hence, EC effects with suboptimally presented CSs would support theories claiming that contingency awareness is not necessary for EC effects to occur. Recent studies reported the absence of EC with briefly presented CSs when both CS and US were presented in the visual modality, even though the CSs were identified at above-chance levels. Challenging this finding, Heycke et al. (R Soc Open Sci 4(9):160935, 2017) found some evidence for an EC effect with briefly presented visual stimuli in a cross-modal paradigm with auditory USs, but that study did not assess CS visibility. The present study realized a close replication of this study, while deviated from it using different stimuli, introducing a brief practice phase, and adding a CS visibility check. Overall EC for briefly presented stimuli was absent, and results from the visibility check show that an EC effect with briefly presented CSs was only found, when the CSs were identified at above-chance levels.