Abstract:

The tip-of-the-tongue (TOT) refers to when a speaker seems to have accessed a word’s meaning adequately but is unable to complete the sound form or phonological label of the word. Both diary studies that document TOT episodes and experimental methods designed to generate TOT have demonstrated that older adults experience more TOT than young or middle-aged adults. With regard to the aging mechanism, the inhibition deficit theory supposed that older adults are more likely than young adults to fail to retrieve the words due to the activation the irrelevant information, which interfere with the retrieval of the target name. The contents of inhibition include limiting access to irrelevant information (access), deleting information that is no longer relevant (deletion), and restraining the production of dominant responses (restrain). This study consisted of two experimental tasks, which were designed to explore the roles of access and deletion functions respectively in TOT among the elderly.

In experiment 1, a 2 (age group: old and young) × 2 (interferential condition: with/without interference) mixed design was adopted to examine the role of access function in TOT among the old adults. In order to investigate the impact of deletion function, 30 young people (aged 18 to 33 years) and 30 older adults (aged 60 to 79 years) were recruited. Participants in interference condition were asked to not pay attention to the interferential stimuli when performing the TOT task. To examine the role of deletion function in TOT among the elderly, a 2 (age group: old and young) × 2 (activating condition: activate interferential stimuli or not) mixed design was adopted in experiment 2. Thirty young people (aged 19 to 27 years) and 30 older adults (aged 61 to 78 years) were recruited for experiment 2 and they were presented the interferential stimuli before the TOT task in the condition of activating interferential stimuli.

A two-way repeated measures ANOVA was used to analyze the data. In experiment 1, the interaction between age and interference condition were significant. Only the old group had significantly higher rates of TOT in the condition with interference than that of those without interference. In order to analyze the role of access function further, we compared the age difference between the 2 conditions, and the age difference in the interference condition was significantly larger. This result indicated that the access function influences the rates of TOT among the old people. In experiment 2, the interaction between age and activating condition was significant. The old group had higher rates of TOT in the condition of activating interferential stimuli, rather than the young group.

The results demonstrated that the deficits in access and deletion functions of older adults may be responsible for the higher rates of TOT, which provided supportive evidence for the inhibition deficit theory. The study implied that intervention on inhibition may be useful in improving the TOT of old adults.

Key words: tip-of-the-tongue, the elderly, inhibition, access, deletion