Is evidence for late selection due to automatic or attentional processing of stimulus identities?
This study determined whether evidence for late selection is due to attention processing or to processing by an automatic system that is separate from attention (two systems framework; Eriksen, Webb, & Fournier, 1990). The task was a two-choice discrimination of a target that appeared in one of two sequentially cued locations in an eight-letter visual display. Attention was directed to the first cued location (cue 1), and whether identification processing occurred at a different location before the second cue (cue 2) directed attention there was determined. Cue validity varied across two experiments, and critical trials were those in which the target appeared at cue 2. For these trials, the target was preceded by a letter (either identical, neutral, or incompatible) that changed to the target at various time intervals following cue 2. Automatic identification was assumed if the incompatible letter interfered with response to the target when it appeared only before cue 2 onset and independent of cue validity. The incompatible letter appearing only before cue 2 onset interfered with the target when the target occurred equally often at cue 1 and cue 2, but not when the target occurred at cue 1 70% and at cue 2 30% of the time. This disconfirms the two systems framework and suggests that attention is required for spatial form processing and response competition.
Fournier
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LR
Department of Psychology, Washington State University, Pullman 99164-4820, USA. fournier@wsunix.wsu.edu
Shorter
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D000328:Adult; D001288:Attention; D004193:Discrimination Learning; D005260:Female; D006801:Humans; D008297:Male; D009949:Orientation; D010364:Pattern Recognition, Visual; D011601:Psychophysics; D011930:Reaction Time