Empirically grounding grounded cognition: the case of color.

Grounded cognition theories hold that the neural states involved in experiencing objects play a direct functional role in representing and accessing object knowledge from memory. However, extant data marshaled to support this view are also consistent with an opposing view that perceptuo-motor activations occur only following access to knowledge from amodal memory systems. We provide novel discriminating evidence for the functional involvement of visuo-perceptual states specifically in accessing knowledge about an object's color. We recorded event-related brain potentials (ERPs) while manipulating the visual contrast of monochromatic words ("lime") in a semantic decision task: responses were made for valid colors ("green") and locations ("kitchen") and withheld for invalid colors and locations. Low contrast delayed perceptual processing for both color and location. Critically, low contrast slowed access to color knowledge only. This finding reveals that the visual system plays a functional role in accessing object knowledge and uniquely supports grounded views of cognition.