On the relationship between spatial attention and semantics in the context of a Stroop paradigm

A controversial issue in the literature on single word reading concerns whether semantic activation from a printed word can be stopped. Several reports have claimed that, even when attention is directed to a single letter in a word, semantic interference persists full blown in the context of variants of Stroop's paradigm. Incidental word recognition is thus claimed to be unaffected by directed spatial attention and hence to be automatic by this criterion. In contrast, the literature examining the relation between intentional visual word recognition and spatial attention in tasks like lexical decision and reading aloud suggests that spatial attention is a necessary preliminary to lexical/semantic processing of a word. These opposing conclusions raise the question of whether there is a qualitative difference between incidental and intentional visual word recognition when spatial attention is considered. We first consider the methodology from Stroop experiments in which putatively narrowed spatial attention manipulations failed to prevent interference from semantics. We then report a new experiment that better promotes focused spatial attention. The results yield clear evidence that the effect of semantic activation can indeed be sidelined because one or more prior processes were in large measure stopped. We conclude that incidental word recognition is not automatic in the sense of occurring without any kind of attention.