The time course of grammaticality judgement

The results of three experiments which investigated the time course of grammaticality judgement are presented. We used sentences that varied in error type (agreement, transposition, omission of function words), part of speech (auxiliaries vs determiners) and location (early vs late error placement). Experiment 1 was a word-by word doze experiment in which subjects were presented with successively longer fragments of a sentence and instructed to complete the sentence grammatically, if possible. Experiment 2 was a self-paced, word-by-word grammaticality judgement experiment. The results of both experiments are quite similar, showing that some error types elicit a broad and variable ''decision region'' instead of a more punctate ''decision point''. To explore the implications of this finding, Experiment 3 looked at on-line judgements of the same stimuli in an RSVP paradigm, with a single response (and reaction time): Correlations among the three experiments were extremely high and all significant, suggesting that the incremental tasks were tapping into the same decision-making process as is found on-line. The implications of these findings for the error types that do and do not appear in aphasia are discussed.