Repetition proportion affects masked priming in nonspeeded tasks

*Research article by Glen E. Bodner & Jeremy C.S. Johnson, University of Calgary, Calgary, Alberta, Canada

Abstract

Masked repetition priming is often greater when a larger proportion of trials involve repetition primes, suggesting that a context-sensitive unconscious process may be operating. Two recent studies have failed to obtain an effect of prime proportion in the perceptual identification (PI) task, suggesting that the effect may not occur in nonspeeded tasks. Contrary to this possibility, we report proportion effects with masked repetition primes in two nonspeeded tasks: PI and fragment completion (FC). A proportion effect occurred in the accuracy measure only in the FC task, but it occurred in the reaction time measure in both tasks. Prior failures to find proportion effects in the PI task thus may have been due, in part, to the dependent measure used. We interpret our findings in light of several recent accounts of prime proportion effects with brief primes.

Executive Summary

The masked priming paradigm is commonly used to evaluate how unconscious stimuli affect responses to consciously perceived targets. A short-duration prime (e.g., horse for 45 msec) is preceded by a premask (e.g., XXXXX for 495 msec) and is followed by a target (e.g., HORSE) to which the subject responds. Using this arrangement, Forster and Davis (1984) found that masked repetition primes (e.g., horse–HORSE) facilitated lexical decisions to word targets, relative to an unrelated-prime control condition (e.g., stair–HORSE). They suggested that this paradigm is useful for isolating the effects of “low-level” lexical processes from those of context-sensitive “high-level” processes (see also Forster, Mohan, & Hector, 2003).

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