Reinstatement of prior processing and repetition priming

Two principal accounts of repetition priming describe either reinstatement of prior processing demands or activation of item-specific representations used in stimulus recognition as mechanisms by which the effect occurs. The former type of account predicts maximal priming when the same task is performed at first and second encounter (i.e. at training and test). The latter type of account predicts priming in any test task that requires access to item-specific representations as long as those items have been recognised earlier, regardless of the training task. An experiment was performed to test these contrasting predictions, in which subjects matched pairs of object pictures on the basis of either the colour of a segment of each object or on the basis of each object's identity. No repetition priming was observed when subjects performed colour matching at both first and second encounter. Priming was observed when responses were made on the basis of identity at both first and second encounter, and there was equivalent priming when colour matching was performed at the first encounter and identity matching at the second encounter. These results pose problems for theories of repetition priming based on reinstatement of prior processing demands, as colour matching did not prime subsequent colour matching (exact reinstatement of processing demands), whereas it did prime subsequent identity matching as much as did prior identity matching (a change in processing demands). These results are consistent with repetition priming occurring within a system that represents the identities of items.