A Matter of Memory? Sentence Comprehension in Healthy Aging

The study of sentence processing in aging has generally resulted in theories that suggest age related declines and deficits. However, most studies of sentence processing in older adults have conflated cognitive function and memory demands with processing itself. The current project aimed to use implicit, non-declarative methods to investigate whether sentence processing declines with age. Additionally, this project examined memory and processing speed dynamics during sentence processing by recording and manipulating memory demands and taking tests of processing speed. Three studies of syntactic priming (Studies 1, 3, and 4) and one study of relative clause disambiguation (Study 2) with older and younger adults are presented. In Studies 1 and 3,reliable syntactic priming was recorded in older and younger adults, suggesting sensitivity to syntax remains stable in older adulthood. Intact syntactic priming in older adults further suggests a non-declarative basis for syntactic priming in general, and similar mechanisms underlying syntactic and lexical effects. Study 4 reports a further analysis of syntactic priming patterns across intervening fillers, the persistence of which has important implications for theories of syntactic priming. Study 2 reports similar patterns of relative clause disambiguation in older and younger adults, and equal susceptibility to memory interference manipulations. Effects of Working Memory and Processing Speed were generally minor and did not relate to implicit processing measures. Taken together, the presented Studies contradict traditional accounts of sentence processing and aging which have described processing impairments. Instead, this project suggests sentence processing itself remains intact with age, and observed deficits in the past are likely the result of explicit memory demands. All studies stress the value of implicit, non-declarative measures of sentence processing to research with older adults, and provide evidence for implicit causes underlying syntactic priming effects.