"Age-Related Differences in Language Production and Semantic Memory Networks"
Michele Diaz, Ph.D
Professor of Psychology, Linguistics, & Neuroscience
Director of Human Imaging: SLEIC of Psychology
Although age is often associated with cognitive change, language abilities show complex patterns of both spared and impaired performance. In this talk, she will discuss two areas of their lab’s research: age-related differences in language production and age-related differences in semantic memory networks. Language production is often associated with age-related differences such as speaking more slowly, having more frequent slips of the tongue, and experiencing more pauses and fillers during speech. While these phenomena are often observed, the underlying mechanism is less clear. To explore these issues, recent work from their lab has examined the neural and behavioral effects of word characteristics such as lexical frequency and neighborhoods (phonological and semantic) in a broad sample of individuals across adulthood. While we observe typical age-related slowing, increases in errors, and increases in functional activation during picture naming, neural and behavioral sensitivity to word characteristics is largely stable across the lifespan. In contrast to language production, semantic memory is generally thought to remain largely stable as we age. Older adults generally have larger and more diverse vocabularies; and demonstrate comparable performance to younger adults when making semantic judgments and during semantic priming tasks. However, the additional information that arises from larger vocabularies and richer experiences incur storage needs. Using a graph theory approach, recent findings from their lab have demonstrated that older adults’ semantic memory networks differ from younger adults. We find that older adults’ semantic networks are less flexible and break down faster than younger adults. Collectively, these findings suggest that while older adults’ sensitivity to phonological and semantic characteristics is stable across the lifespan, the underlying representation and access to that information may decline with age.