Concepts are not represented by conscious imagery.

According to theories of grounded cognition, conceptual representation and perception share processing mechanisms. We investigated whether this overlap is due to conscious perceptual imagery. Participants filled out questionnaires to assess the vividness of their imagery (Questionnaire on Mental Imagery) and the extent to which their imagery was object oriented and spatially oriented (Object-Spatial Imagery Questionnaire), and they performed a mental rotation task. One week later, they performed a verbal property verification task. In this task, involvement of modality-specific systems is evidenced by the modality-switch effect, the finding that performance on a target trial (e.g., apple-green) is better after a same-modality trial (e.g., diamond-sparkle) than after a different-modality trial (e.g., airplane-noisy). Results showed a modality-switch effect, but there was no systematic relation between imagery scores and modality switch. We conclude that conscious mental imagery is not fundamental to conceptual representation.