Theoretical approaches to language and aging

Abstract Research on cognition and aging has developed rapidly over the past several decades, moving beyond its early focus on psychometric intelligence tests to encompass new experimental paradigms and theoretical frameworks from cognitive psychology and the neurosciences. Although the accumulation of empirical findings has overshadowed the development of theories for explaining the patterns of cognitive change in old age, specification of theories of cognitive aging has undergone recent progress (e.g. Bowles 1994; Byrne 1998; Hasher and Zacks 1988; MacKay and Burke 1990; Myerson et al. 1990; Salthouse 1996). In this chapter, we describe a detailed theory of cognitive aging, the Transmission Deficit hypothesis, comparing it to other theories and demonstrating its account of evidence relating aging and language. We start with evidence indicating that effects of aging on language comprehension versus production are asymmetric, a phenomenon that sets a boundary condition for theories of cognitive aging. Although theories of cognitive aging have in general focused on cognitive decrements, these asymmetries indicate that they must also account for domains of performance that are preserved in old age, such as language comprehension. We compare two classes of cognitive aging theories for explaining asymmetric effects of aging on language: infonnation-universal and information-specific theories. Then we provide a detailed account within the Transmission Deficit model of how aging impacts three aspects of language production: tip-of-the-tongue experiences (TOTs), proper name recall, and retrieval of orthographic knowledge.