Spatial configuration of vertically related word pairs modulates the N400 component

This study examined the effect of spatial iconicity on the N400 component. Spatial iconicity is defined as the spatial arrangement of words on a screen relative to the spatial arrangement of their referents (e.g. attic-basement). In two experiments, electroencephalograms were recorded in 32 participants while performing a semantic relatedness judgment task on pairs of words that were either related or unrelated. All of the related word pairs were parts of objects that shared a vertical spatial relationship. In Experiment 1, the words of each pair were presented simultaneously on top of one another. Results showed that related word pairs presented in a spatial arrangement that mismatched the spatial relationship of their referents were associated with increased error rates as well as larger N400 components known to index semantic/conceptual processing cost. These findings thus suggest that the words automatically activated visuospatial simulations of their referents and that semantic/conceptual processing difficulty arose when the vertical arrangement of the word pairs was inconsistent with those simulations. In line with this interpretation, these effects were not present in Experiment 2 when the words of each pair were presented in succession in the middle of the screen. Overall, these results provide evidence that perceptual simulations contribute to some of the underlying processes of the N400 component (see video abstract, Supplemental digital content 1, http://links.lww.com/WNR/A304).