Brainwaves are stethoscopes: ERP correlates of novel metaphor comprehension

The processing of unfamiliar metaphors was examined using event related potentials (ERPs). We compared the patterns of brain electrical activity elicited by processing two-word expressions denoting literal, conventional metaphoric, and novel metaphoric meaning, as well as unrelated word pairs. Participants performed a semantic judgment task in which they decided whether each word pair conveyed a meaningful expression. N400 amplitude to the second word of the pair varied as a function of expression type in a graded manner increasing from literal expressions to conventional metaphors, to novel metaphors and to unrelated pairs. N400s elicited by novel metaphors showed a right-biased scalp distribution as compared to those elicited by conventional metaphors. Novel metaphors also elicited a right-sided late negativity suggesting further attempts to integrate meaning in a non-literal fashion, a result that supports the sequential view of novel metaphor comprehension. These findings are consistent with recent brain imaging studies and complement them by adding the temporal dynamics dimension. (C) 2007 Elsevier B.V. All rights reserved.