Abstract
Visual search is sometimes slowed when a previously rewarded versus unrewarded distractor is present. This so-called "value-driven attention capture" (VDAC) is widely viewed as a perceptual phenomenon; positive reward history is thought to boost a stimulus's representational strength regardless of current motivational contexts (e.g., task relevance), thus causing inappropriate attention capture (or VDAC). Alternatively, motivation could drive attention and account for VDAC via on-line computations of cost versus benefits for processing specific stimulus features. If so, then VDAC should depend on current motivational contexts, rather than on selection history alone. In this view, any concurrent secondary task, e.g., a working memory (WM) task, involving the reward-associated distractor feature should alter the cost/benefit tradeoff for this feature and consequently modulate VDAC. However, if VDAC is driven by selection history alone, then such manipulations should have no effect. To investigate, we conducted a conventional two-phase VDAC experiment, but added a concurrent visual WM task to the second, non-rewarded visual search phase in which reward-associated distractors are presented. The WM task involved maintaining either (a) colour (the reward-associated feature), or (b) shape (the target-defining feature) information during each search trial. WM tasks were matched for difficulty. We predicted that a colour WM task would increase the cost of processing the reward-associated distractor feature (colour), thus reducing motivation for processing it, and obliterating VDAC. In contrast, the shape WM task should increase shape processing costs, leaving motivation to process the distractor colour unaffected and enabling VDAC. Consistent with this motivation-driven account, VDAC was absent with a colour WM task but robust with a similarly difficult shape WM task. These effects show that selection history alone cannot account for VDAC; instead contextually determined motivational cost-benefit tradeoffs appear to drive attention and reward-association effects on processing.
Meeting abstract presented at VSS 2018