The TOT-object paradigm: Towards a greater understanding of speech disfluencies during tip-of-the-tongue states in older adults

Existing literature on speech disfluencies in healthy aging often categorizes disfluencies as word-finding difficulties. However, it is important to acknowledge the multitude of potential underlying causes that contribute to speech disfluency and a more fine-grained analysis of disfluencies is needed. To this end, the current study used an experimental paradigm that can lead to the production of disfluencies due to Tip-Of- the-Tongue (TOT) states, which reflect word-finding difficulties with a phonological origin. Twenty-seven younger (aged <25 y/o) and 26 older (aged 60 – 72 y/o) participants performed a picture naming task involving newly learnt non-existing objects (TOT-objects) which were used to evoke TOT states. This study had two objectives: a) testing the potential of this paradigm to analyze TOTs and TOT resolution, and b) performing exploratory analyses of disfluencies related to TOT states and comparing those across the two age groups. The TOT-object paradigm elicited a substantial number of TOTs, making it suitable for examining these phenomena. We found no significant effect of age group on the number of TOTs. However, TOT states manifested themselves differently in younger and older participants. Sensitivity analyses indicated that older participants produced significantly more phonological errors during TOT states than younger participants, while younger participants showed a greater tendency towards silent pauses. These findings suggest that different causes underly TOTs in both age groups in younger and older adults.