Global/local processing and negative priming: the influence of selection difficulty and stimulus exposure

Negative priming is a decrement in performance observed when a previously i gnored stimulus is re-presented as a target. The present study examined the relation between selection difficulty and negative priming in five experim ents that used hierarchical stimuli (large letters made up by small letters ). The results show that negative priming is greater when subjects direct a ttention to the local level (more difficult selection) than when they direc t attention to the global level (less difficult selection). However, that o ccurs only when exposure of prime and probe is sufficiently long. With shor ter presentations, negative priming is still observed but is no longer modu lated by selection difficulty. These results suggest that both anticipatory and reactive mechanisms are responsible for the occurrence of negative pri ming and that instantiation of the reactive mechanism depends on the time a vailable for prime and probe selection.