Abstract
In visual singleton search, interference by salient singleton distractors can be more effectively overcome if they consistently appear at particular, i.e. 'frequent' – vs. 'infrequent' – display locations (Goschy et al., 2014). The present study investigated whether this "location probability cueing" effect is spatial in nature or dependent on the feature/dimension relationship of the distractor to the search target. Thirty-two observers searched for a slightly left- or right-tilted target bar among 35 vertically oriented gray bars. In half of the trials, one of the non-targets was a horizontal gray bar (i.e. same-dimension distractor). This compares with Goschy et al.'s (2014) study, in which the target was the same slightly tilted bar and the distractor a red (vertical) bar (i.e. cross-dimension distractor). The results revealed that (i) overall interference was higher with same- than with cross-dimension distractors (Cohen's d = 3.51 vs. d = 1.55); (ii) with same-dimension distractors, search was impaired for (orientation) targets appearing in the 'frequent' (orientation) distractor region, even when no distractor was actually present on a trial (d = .59) – an effect pattern not evident in the cross-dimension condition; (iii) with same-dimension distractors, although participants learn to shield search from distractors in the frequent region to some degree, the interference remains significant even after extended practice – in contrast to the cross-dimension condition where interference is effectively abolished after 8 blocks of 100 trials. This pattern of results suggests distractor shielding is critically dependent on the dimensional relationship between target and distractor: the target is spatially suppressed in the frequent distractor area only when it is defined in the same dimension as the distractor, but not when it is defined in a different dimension – consistent with the 'dimension-weighting account' of visual singleton search.
Meeting abstract presented at VSS 2016