Repetition proportion affects masked priming in nonspeeded tasks

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.