The monitoring theory of language perception proposes that competing representations that are caused by strong expectancy violations can trigger a conflict which elicits reprocessing of the input to check for possible processing errors. This monitoring process is thought to be reflected by the P600 component in the EEG. The present study further investigated this monitoring process by comparing syntactic and spelling violations in an EEG and an fMRI experiment. To assess the effect of conflict strength, misspellings were embedded in sentences that were weakly or strongly predictive of a critical word. In support of the monitoring theory, syntactic and spelling violations elicited similarly distributed P600 effects. Furthermore, the P600 effect was larger to misspellings in the strongly compared to the weakly predictive sentences. The fMRI results showed that both syntactic and spelling violations increased activation in the left inferior frontal gyrus (lIFG), while only the misspellings activated additional areas. Conflict strength did not affect the hemodynamic response to spelling violations. These results extend the idea that the lIFG is involved in implementing cognitive control in the presence of representational conflicts in general to the processing of errors in language perception. © 2010 Elsevier Inc. All rights reserved.
General introduction"Mistakes are a fact of life. It is the response to error that counts" (Nikki Giovanni). This quote nicely illustrates that we are bound to make mistakes but that we can also use the thereby obtained information to adjust our behaviour. To learn from our mistakes, however, we must be able to detect them. The detection of errors and the adjustments in behaviour require cognitive control. Cognitive control processes manage and guide other cognitive processes according to internal goals. One aspect of cognitive control is monitoring, which deals with the detection and repair of errors. Errors occur when there is a mismatch between what we intend or expect and what we do or observe. When such a mismatch is detected, compensatory adjustments are triggered in the processing pathways that are involved, leading to a repair.Mistakes, of course, occur in various domains, and here we are interested in the language domain. In this field, the main focus has been on error monitoring in language production. For language production, researchers have been interested in speech errors and their repairs (for a review see Levelt, 1983). However, in language perception error monitoring takes place as well. For example, sometimes we mishear what another person is saying and ask for a clarification: "Did I understand you correctly…?". Another type of perceptual language errors are mistakes that are made while reading a text. Kaufman and Obler (1995) call these 'slips of the eye', and showed that normal adult readers make various kinds of these errors. For instance, sometimes words are inserted, omitted or exchanged, the parsing of a word or sentence can be erroneous (e.g., reading posts as...