Single and multiple object naming in healthy ageing

Abstract

We compared the performance of young (college-aged) and older (50+years) speakers in a single object and a multiple object naming task and assessed their susceptibility to semantic and phonological context effects when producing words amidst semantically or phonologically similar or dissimilar words. In single object naming, there were no performance differences between the age groups. In multiple object naming, we observed significant age-related slowing, expressed in longer gazes to the objects and slower speech. In addition, the direction of the phonological context effects differed for the two groups. The results of a supplementary experiment showed that young speakers, when adopting a slow speech rate, coordinated their eye movements and speech differently from the older speakers. Our results imply that age-related slowing in connected speech is not a direct consequence of a slowing of lexical retrieval processes. Instead, older speakers might allocate more processing capacity to speech monitoring processes, which would slow down their concurrent speech planning processes.

Acknowledgements

This research was funded by a postdoctoral scholarship from the German Academic Exchange Service (DAAD D/02/00789) and a grant from the German Research Foundation (BE-3176/2-1) to the first author. We thank Debra Malpass for her assistance in conducting this research.

Notes

¹Griffin (2003) found a similar pattern of results when she tested participants from different student populations (from Stanford University and Georgia Institute of Technology) in two parallel experiments. The groups did not differ in speech onset times, but Georgia Tech students were slower to articulate the first object name. This was accompanied by longer pre-speech gaze durations to the first object.

²In addition, there was a main effect of position, F ₁(2, 60) = 17.97, p = .001, CI = 23 ms; F ₂(2, 62) = 127.77, p = .001, CI = 26 ms, with the gazes to the first (leftmost) object being significantly longer than the gazes to the second and third object. There were no interactions between object position and semantic or phonological relatedness.