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Word retrieval in ageing: An exploration of the task constraint hypothesis

Gordon, Jean K. and Kindred, Nicole K.
Word retrieval in ageing: An exploration of the task constraint hypothesis. Aphasiology, 25(6-7), 2011, pages 774-788.

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Abstract

Background: Among the factors that influence word retrieval are characteristics of the stimulus (e.g., length, frequency), characteristics of the individual (e.g., age, education), and characteristics of the task itself. Task factors have not been studied as thoroughly as stimulus and individual factors; in fact, it is often implicitly assumed that groups should be expected to perform similarly in any task involving lexical retrieval.

Aims: This assumption was explicitly investigated in the current study by comparing word retrieval in healthy younger, middle-aged and older adults using three tasks with different stimulus and response characteristics. We hypothesised that the degree of constraint of the task would negatively affect word-retrieval performance in normally ageing participants.

Methods & Procedures: Word retrieval was examined in three tasks: picture naming, vocabulary definition, and verbal fluency. The relationship of performance to age and education within each task, and the relationships of performance across tasks, were examined in order to clarify the nature of age-related word-retrieval decline.

Outcomes & Results: Age-related declines in word retrieval were found in picture naming and verbal fluency tasks, whereas an age advantage was found for vocabulary definition.

Conclusions: The task constraint hypothesis was partly supported. Unanticipated results require a revision of the hypothesis to take into account the nature of the constraints in each task, relative to the mechanisms underlying age-related declines in lexical retrieval.

EPrint Type:Journal (Paginated)
Keywords:Ageing, Lexical access, Task factors
Subjects:UNSPECIFIED
ID Code:2234
Conference:Clinical Aphasiology Conference: Clinical Aphasiology Conference (2010 : 40th : Isle of Palms, SC : May 23-27, 2010)
Publication:Aphasiology
Volume:25
Number:6-7
Pages:774-788
Alternative Locations:http://dx.doi.org/10.1080/02687038.2010.539699
DOI or Unique Handle:10.1080/02687038.2010.539699
Additional Information:This article is based on a paper originally presented at the CAC2010 Conference. Permission to view the full-text article is subject to the publisher's access restrictions.

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