Abstract
In visual search, a working memory representation of the search target guides attention to similar items, and is used to verify whether an inspected item is the target. Research comparing picture to text-based search cues finds that picture cues produce better guidance (reduced time to first fixate the target) and shorter verification times (reduced time between fixating the target and response). These findings suggest that a high fidelity working memory representation benefits both search guidance and target verification. Here we investigated the source of this picture cue benefit to determine how the cue's visual form and/or color information differentially impact guidance and verification times. Given that visual acuity drops precipitously with eccentricity, visual form information may be unlikely to influence guidance to the periphery, but may benefit verification. By contrast, color information is likely to influence guidance but may have little influence on verification times. To test the impact of color and visual form information, subjects searched colored arrays of photo-realistic objects while we manipulated the cue type. Cues were gray-scaled pictures, color pictures, text labels, or text-labels with color information (e.g., "blue shoe"). Tracking eye movements allowed us to parse reaction times into guidance and target verification phases. Results show that color information improved guidance, and did so to a similar extent for both picture and text cues. To our surprise, form information also improved guidance and this improvement was additive with the color benefit, and of about the same magnitude. In terms of verification times, form information reduced verification times, but color information did not reduce verification times for text-based cues. Finally, during guidance, color's impact occurred within the first fixation while the benefit of form information was slightly delayed. These results suggest unique impacts of form and color information on search guidance and target verification processes.
Meeting abstract presented at VSS 2017