Depth of conceptual knowledge modulates visual processes during word reading.

Recent evidence suggests that conceptual knowledge modulates early visual stages of object recognition. The present study investigated whether similar modulations can be observed also for the recognition of object names, that is, for symbolic representations with only arbitrary relationships between their visual features and the corresponding conceptual knowledge. In a learning paradigm, we manipulated the amount of information provided about initially unfamiliar visual objects while controlling for perceptual stimulus properties and exposure. In a subsequent test session with electroencephalographic recordings, participants performed several tasks on either the objects or their written names. For objects as well as names, knowledge effects were observed as early as about 120 msec in the P1 component of the ERP, reflecting perceptual processing in extrastriate visual cortex. These knowledge-dependent modulations of early stages of visual word recognition suggest that information about word meanings may modulate the perception of arbitrarily related visual features surprisingly early.