Abstract
The search template is a specific type of visual working memory (VWM) representation that facilitates search by guiding attention toward matching features when they appear in view. In a series of experiments we tested whether the pupil response and microsaccades can be used to track attentional guidance by the search template and differentiate this process from recognition of other VWM contents. Participants memorized either one or two colored circles to be searched for later on. When two circles were presented, a retro-cue indicated which one of the two was relevant for the upcoming search task (the template). Crucially, before the search display appeared, we briefly presented one or two colored probe stimuli. These probes could match the color of either the relevant-template color, the irrelevant color, or it could be a new color unrelated to the items in memory. We measured the pupil response to the probe display and the amount of microsaccades to the template matching probe as a signature of attentional guidance. Overall, the pupil showed significantly more constriction in response to memory matching probes than for unrelated colors. However, this effect seems to be driven by the recognition of the memory items in the probe display rather than by the relevance of each item. In contrast, microsaccades were consistently directed towards probes matching the relevant color. Taken together, both the pupil and microsaccades were sensitive to when information was previously presented but only microsaccades could distinguish the search template from other VWM representations.
Meeting abstract presented at VSS 2016