Influence of speaking rate and lexical status on word identification

At a recent meeting of this Society, we reported that two factors which contribute to the identification of a word within a sentence, the speaking rate at which the sentence is produced, and the semantic relation between the sentence and the target word, operate quite differently: Slight changes in task demands were found to readily eliminate the semantic effect, whereas the rate effect was obtained regardless of the specific task conditions used. These results suggested that in the course of identifying a word, the processing system optionally takes into account the semantic content of the context sentence, but necessarily takes into account its rate. In the present investigation, we have been asking whether a comparable distinction holds at the level of a single word. Specifically, we are comparing how the lexical status of a syllable (whether it is a real word or a nonsense word) and its speaking rate (specified by syllable duration) influence identification. As expected under the hypothesis that rate information plays an obligatory role during processing, we have found that identification is influenced by speaking rate under the variety of task conditions tested. We have also found, however, that the lexical status of the syllable influences identification under all the conditions tested. This result, if supported by additional tests currently underway, would suggest that lexical information, unlike word-external semantic information, may necessarily be accessed during processing and, like speaking rate, obligatorily influence identification. [Research supported by NIH.]