Ostarek, M. 1 & Huettig, F. 1, 2
1 Max Planck Institute for Psycholinguistics, Nijmegen
2 Donders Institute for Brain, Cognition, and Behavior, Radboud University, Nijmegen
The notion that processing spoken (object) words involves activation of category-specific representations in visual cortex is a key prediction of modality-specific theories of representation that contrasts with theories assuming dedicated conceptual representational systems abstracted away from sensorimotor systems. In the present study, we directly tested whether low-level visual cortex is involved in spoken word processing. Using continuous flash suppression we show that spoken words activate behaviorally relevant low-level visual representations and pin down the time-course of this effect to the first hundreds of milliseconds after word onset. We investigated whether participants (N=24) can detect otherwise invisible objects (presented for 400ms) when they are presented with the corresponding spoken word 200ms before the picture appears. Our results showed facilitated detection for congruent vs. incongruent pictures in terms of hit rates (z=-2.33, p=0.02) and d'-scores (t=3.01, p<0.01). A second experiment (N=33) investigated the time-course of the effect by manipulating the timing of picture presentation relative to word onset and revealed that it arises as soon as 200-400ms after word onset and decays at around word offset. Together, these data strongly suggest that spoken words can rapidly activate low-level category-specific visual representations that affect the mere detection of a stimulus.