Recent work suggests that monitoring in
speech production may occur via domain-general mechanisms responsible for detecting response conflict. To test this hypothesis, we measured EEG as people engaged in both non-verbal (flanker) and verbal (tongue twisters) tasks designed to elicit response conflict and errors. In the
flanker task, people pressed a button corresponding to whether a center arrow
was facing left or right, and response
conflict was induced with flanking arrows pointing in the same (congruent; >>>>>) or a different (incongruent >><>>) direction. In the tongue twister task, people read sequences of four nonwords three times in which rhymes alternated in an ABAB pattern while onset speech sounds alternated in an ABBA (tongue twister) or
an ABAB (non-tongue twister) pattern (e.g., tif deev dif teev vs. tif teev dif deef). Results in the fl anker task showed standard markers of response conflict in the form of an increased N2 for incongruent relative to congruent trials as well as an error-related negativity (ERN) for incorrect trials. Behaviourally, more errors were elicited for tongue twisters relative to nontongue twister trials, and an ERN was observed on incorrect responses.
Correlations between the magnitude of the N2 and ERN in the fl anker task with the magnitude of the ERN and error rates in the tongue twister task are consistent with a common underlying locus. Adaptation effects preceding and following erroneous trials in production are also presented. These results are consistent with response confl ict serving as a cue to monitoring
in speech production.