Word production within sentence contexts: the role of cognitive ageing

Although the process of word production is seemingly effortless for most healthy adults, word retrieval declines with age (e.g., Condret-Santi et al., 2013). Words are usually produced within sentences of ongoing speech produced by speakers and their conversational partner(s). Sentence contexts can influence word retrieval in younger adults during production, causing facilitation when they predict the word to retrieve, but potential interference when speakers must retrieve an unexpected word instead. In this thesis, I studied these sentence-context effects, and the mechanisms underlying them, in healthy younger and older adults. Furthermore, I studied how potential age-related changes in word production might relate to other cognitive mechanisms argued to change with ageing, focusing on semantic control.
Through the empirical work in this thesis, I firstly examined how word production is influenced by sentence contexts predicting different types of target words in both younger and older adults (Chapter 2). I also examined the cognitive mechanisms that might relate to word production in ageing (Chapter 3). In Chapter 4, I further explored how the position of critical information (predicting the target word) in a sentence affects word production. In the final empirical chapter, I explored the effects of degree of unexpectedness on word production, while also manipulating the role of semantic competition.
Collectively, the findings suggest older adults’ word production continues to benefit from sentence context. Preserved semantic networks might allow older adults to keep using priming and/or prediction in sentence contexts to aid their word retrieval. Although some declines in older adults’ semantic and general cognitive control were observed, older adults did not show greater difficulties with unexpected or otherwise highly demanding sentence contexts than their younger counterparts. The assimilation of the traditional picture-naming paradigm within sentence contexts was an important step towards understanding how older adults’ language changes within daily-life speech contexts.