The effect of midazolam on the modality-match effect in implicit memory.

Prominent theories of implicit memory claim that perceptual processes play a central role in implicit memory. The modality-match effect, the finding that priming is greater when the modality of stimulus presentation matches at study and test, provides the central evidence for these approaches. In this paper we use the benzodiazepine, midazolam, to explore the nature of the modality-match effect in implicit memory. We compared the modality-match effect in a midazolam and a saline (i.e., a placebo) condition. Our experimental results demonstrate that the modality-match effect is diminished substantially in a midazolam condition even though components of priming are preserved. Given the empirically-validated assumption that midazolam minimizes explicit memory, these results suggest that there exist components of implicit memory that are not mediated by perceptual processes and raise questions about the generality of prominent theories of implicit memory.