Abstract
The concept of a "template for rejection", or the activation of distractor visual information to benefit subsequent target detection, has been hotly contested in recent years. Is a distractor enhanced like a target with an additional "tag" that it should be rejected once it has been detected during search? Or is it already inhibited during the preparatory period, biasing attention towards other features (including the target) of the upcoming search display? Here, subjects were required to detect a target in an array containing four items of one color and four items of a second color, while undergoing fMRI. One of the two colors was cued beforehand as positive ("the target will appear in this color"), negative ("only distractors will appear in this color"), or neutral ("this color will not appear in the search display"). We used representational similarity analysis within different regions of visual cortex to investigate how distinctly these colors are represented in preparation for search, given the advanced knowledge that they provide information on targets, distractors, or neither. Results revealed more distinct patterns following positive cues compared to negative and neutral cues, whereas negative and neutral cues did not show significantly different levels of color representation distinctiveness. This study is the first to provide evidence that visual features of distractors are represented less distinctly in visual cortex compared to targets during preparation for search, supporting the hypothesis that searchers can strategically use a template for rejection that is functionally distinct from a target template.
Meeting abstract presented at VSS 2018