Effects of verb complexity on speech errors.

Two experiments examined whether semantically related verbs that contrast with respect to the absence versus the presence of an additional semantic feature differentially compete for selection during the encoding of a sentence for production. In both experiments, a speech error induction task was used to elicit contextual (misordering) errors involving semantically related verbs that contrasted only in their semantic complexity or in both their semantic and morphophonological complexity. The prediction was that an asymmetry in contextual errors would be observed in which the more complex verbs would replace the simpler verbs more often than the reverse. This prediction was confirmed in both experiments, with more perseverations and anticipations involving the semantically more complex verb of antonym pairs in Experiment 1, and more perseverations and anticipations involving the semantically more-specified verb of a heavy-light pair in Experiment 2. The implications of the results for spreading-activation theories of language production are discussed.