Abstract
Mounting evidence suggests that monetary reward induces an implicit selection bias toward highly rewarded features. Whether reward has similar effects on spatial attention, however, has been controversial. Here we ask whether spatial biases toward highly rewarded locations are learned implicitly, or are instead biases in choice driven by explicit knowledge of reward structure. Participants completed a hybrid search/choice task involving multiple targets among multiple distractors. Targets garnered varying magnitudes of reward, and participants were instructed to search for targets and guess and click on the one that they think will yield the highest reward on each trial. Unbeknownst to participants, one side of the display offered higher reward than the other side of the display. We measured the spatial bias for targets on the high-reward side of the screen and probed explicit awareness via a multi-question post-task interview. Participants who were aware of the reward structure (N=48) showed a selection bias for targets appearing on the high-reward side of the screen. Contrary to previous findings, unaware participants (N=24) showed only a central bias, despite spending as much time as aware participants on the task. The strong association between explicit awareness and reward-driven spatial attention distinguishes this form of attention from other kinds of implicit guidance of spatial attention, as well as implicit selection biases toward highly rewarded non-spatial features.
Acknowledgement: National Sciences Foundation Graduate NRT Program