Aging, Gesture Production, and Disfluency in Speech: A Comparison of Younger and Older Adults.

Abstract

Age-related changes are observed in the speech and gestures of neurotypical individuals. Older adults are more disfluent in speech and use fewer representational gestures (e.g., holding two hands close to each other to mean small), compared to younger adults. Using gestures, especially representational gestures, is common in difficult tasks to aid the conceptualization process and to facilitate lexical access. This study investigates how aging can affect gesture production and the co-occurrence between gesture and speech disfluency. We elicited speech and gesture samples from younger and older adults (N = 60) by using a painting description task that provided concrete and abstract contexts. Results indicated that albeit the two age groups revealed comparable overall speech disfluency and gesture rates, they differed in terms of how their disfluencies and gestures were distributed across specific categories. Moreover, the proportion of speech disfluencies that occur with a gesture was significantly higher for younger than older adults. However, the two age groups were comparable in terms of the proportion of gestures that were accompanied by a speech disfluency. These findings suggest that younger adults' language production system might be better at benefiting from other modalities, that is, gesture, to resolve temporary problems in speech planning. However, from a gesture perspective, it might be difficult to differentiate between gestures' self-oriented and communicative functions and understand their role in speech facilitation. Focusing on specific cases where speech disfluency and gestures co-occur and considering individual differences might bring insight into multimodal communication.