Attentional capture by reward-distractors under perceptual load

As affective influences, emotional and motivational characterization of information share common mechanisms that shape a large range of cognitive functions. In this line, reward-signaling stimuli have been repeatedly reported as particularly powerful in capturing visual spatial attention even when they are physically non-salient or irrelevant for the task at hand. This so-called value-driven attentional capture (VDAC) led to the proposal that reward-stimuli might attract our attention in an automatic way. However, only a few studies have put the VDAC automaticity to the test by investigating whether cognitive control could counteract attentional capture by reward-distractors. As a cognitive control framework, the Load Theory (Lavie, 2005) has provided converging evidences for reduced distraction by salient, but unrewarded, distractors under high perceptual load condition. We therefore investigated whether visually salient distractor stimuli associated with a monetary reward could still capture attention when the task at hand involves a high perceptual load. Participants had to report the identity of a target-letter (H or S, displayed on the side of a central fixation sign) while ignoring a peripheral irrelevant but salient distractor letter (also H or S) whose color (red or green) signaled high or low reward outcomes (in case of fast and accurate responses). The distractor-letter could either be compatible (same letter) or incompatible (different letter) with the expected target-letter response. The perceptual load was manipulated through a well-used go/nogo paradigm where the go/nogo cue was defined by simple feature detection (i.e., low perceptual load) or a feature conjunction (i.e., high perceptual load). Our results revealed that both high and low salient reward-distractors produced a significant compatibility effect under low perceptual load. However, the compatibility effect was abolished for low-reward distractors only under high perceptual load. We concluded that reward drastically weighs on stimulus priority for attentional selection, leading to automatic VDAC.