DOES INHIBITION OF RETURN OCCUR IN DISCRIMINATION TASKS

When attention is drawn to a location and then withdrawn, responding t o a stimulus at that location may be slower than to one at a new locat ion. This ''inhibition of return'' (IOR) has not been reliably demonst rated in tasks that require discrimination of targets from nontargets. The present experiments replicated IOR in detection and localization tasks only when target/nontarget discrimination was not also required. When discrimination was required, a consistent same-location advantag e occurred for repeated targets. Changed targets may, however, induce a bias toward opposite responses. The results cast doubt on IOR as a g eneral attentional phenomenon.