Priming by “predictive” context stimuli in visual classification

Subjects participated in visual character- and word-classification-tasks-for-which-spatially contiguous context stimuli were exposed 100 or 1,000 msec prior to target onset. These context stimuli were physically identical to the target on 75% of the trials. Substantial facilitation of RT occurred for “valid” trials at both SOA levels. When the target differed from the context stimuli, evidence for priming the response category, as well as the semantic category of the target (letters vs. digits; metal names vs. furniture names), was obtained at the 100-msec SOA, but these effects were attenuated with the 1,000-msec SOA. With a full second to process a stimulus-predictive cue, subjects appear to develop a stimulus-specific expectation of the target that does-not-involve maintaining the category or response-mapping codes that are active with shorter delays