Enhanced early visual processing after evaluative conditioning

Abstract

The emotional significance of a stimulus is known to influence attentional selection leading to prioritization even at early stages of visual perception (e.g., selection from iconic memory). However, as the emotional meaning can be confounded with physical stimulus properties, it is possible that the prioritization is not driven by emotional factors alone. Here we use evaluative conditioning to manipulate the emotional meaning of arbitrary visual stimuli by repeatedly pairing each stimulus with either positive, negative, or neutral pictures. The subjective liking of conditioned stimuli (CSs) revealed reliable evaluative conditioning effects. Sensory processing advantages were measured by presenting the CSs in an iconic memory task asking participants to identify a target in a display of briefly presented stimuli. An adaptive variation of exposure durations revealed that shorter durations were required for the recognition of targets that were previously paired with negative or positive images than for neutral targets, indicating prioritized selection of affective CSs from iconic memory. Two additional experiments investigated the subsequent decay of information that was initially available in iconic memory by manipulated the delay of the recognition cue. Results show that positive CSs were more likely to be selected from iconic memory than neutral CSs, whereas negative CSs were prioritized in terms of prolonged availability in iconic memory. Taken together, the findings suggest that the affective learning history leads to prioritization at the level of iconic memory.