Disfluency across the lifespan: An individual differences investigation.

Abstract

In this study, we had two main research objectives. The first was to examine age-related differences in the fluency of speech outputs, as prior research is filled with conflicting findings concerning whether older adults produce more disfluency compared to younger adults. The second objective was to examine several cognitive individual differences, and the relationship between them and the production of disfluency. One hundred and fifty-four adults completed a story re-telling task, and a battery of cognitive measures. Results showed that younger adults produced more um’s and fewer repetitions. With respect to individual differences, results showed that inhibition and set shifting were related to the tendency to produce repetitions, and inhibition and working memory were related to rates of uh production. Our results provide some clarification about mixed findings with respect to age and disfluency production. The individual differences results provide some clarification on theoretical arguments for disfluent speech in aging (e.g., Inhibition Deficit Hypothesis), and also for the role of executive functions in models of language production.