Measuring the spread of spreading suppression: A time-course analysis of spreading suppression and its impact on attentional selection

We report three experiments investigating the time course of spreading suppression in visual search using preview conditions. A novel color-change procedure was employed in which a target letter changed into a new (singleton) color at various intervals after the onset of the search display. Performance when the singleton was unique across both preview and search displays was compared with that when the singleton carried the color of the preview display. Relative to the unique singleton baseline there were no costs to targets carrying the preview color when the singleton onset occurred shortly (80 ms) after the onset of the new, search display; however, costs emerged as the SOA increased before subsequently decreasing again. In addition, relative to when all the items appeared together (the full-set search baseline), there were benefits when the singleton replaced a target carrying the same color as the distractors in a search display, with the facilitation effect showing a marginal effect at an earlier time than the cost found when the change was to the preview color. The data suggest that there are contrasting time courses to attentional guidance to targets and the suppressive rejection of distractors in visual search. (C) 2009 Elsevier Ltd. All rights reserved.