Susan L. Goldman
MIT, Rm. 36-749, Cambridge, MA 02139
Thomas D. Carrell
Northwestern Univ., Evanston, IL 60208
Previous research has reported that because content words tend to be stressed and function words tend to be unstressed, word class (content-function word) perceptual differences are an artifact of stress differences [A. Cutler and D. Foss, Language Speech 20, 1--10 (1977)]. The present research provides evidence for the validity of word class differences for gated words in a sentence context. Subjects heard successively longer presentations of each target word. The first presentation included the sentence up to the target word onset. The second presentation included the same sentence context plus the first 50 ms of the target word. The duration of each successive presentation was 50 ms longer than the previous presentation. After each presentation, subjects were asked to identify the target word. The target words were content and function words balanced for stress. The results demonstrated that word class, independent of stress, significantly influenced the number of presentations required for identification. The results also showed that for the first presentation, subjects significantly chose words of the same word class as the target word, indicating that word class information is available before phonetic information. [Work supported by Northwestern University dissertation year grant.]