Interaction of semantic and perceptual processes in repetition blindness

Two experiments examined the effect of activation of higher-level semantic representations on lower-level perceptual representations. A forced-choice discrimination paradigm was used, a method known to produce repetition blin dness (RB) for words unconfounded by memory demands or response bias. In Ex periment 1, equivalent reductions in RB (as measured by omission error rate and by d') occurred when successive word pairs were identical in: (1) form , pronunciation, and meaning (both uppercase versions of the same word); (2 ) pronunciation and meaning but not form (lowercase versus uppercase; lexic al identity); and (3) pronunciation, but not form or meaning (homonyms; pho nological identity), relative to when the words were unrelated on all dimen sions. The RB effect was markedly attenuated, but not eliminated, when the words were semantically related. Similar results were obtained in Experimen t 2 using a larger group of subjects. These findings show that higher-order semantic representations can have a top-down influence on judgements based on lower-order perceptual representations. The results are discussed withi n the framework of a cascade model of object processing in the human brain.