Working memory in the oldest-old: evidence from output serial position curves.

In the present study, we examined adult age differences in short-term and working memory performance in middle-aged (45-64 years), young-old (65-74 years), old-old (75-89 years), and oldest-old adults (90 years and over) in the Louisiana Healthy Aging Study. Previous research suggests that measures of working memory are more sensitive to age effects than are simple tests of short-term memory Bopp and Verhaeghen (Journal of Gerontology: Psychological Sciences 60:223-233, 2005), Myerson, Emery, White, and Hale, (Aging, Neuropsychology, and Cognition 10:20-27, 2003). To test this hypothesis, we examined output serial position curves of recall data from three span tasks: forward and backward digit span and size judgment span. Participants' recall patterns in the size judgment span task revealed that the two oldest groups of adults showed the largest decreases in recall performance across output serial positions, but did not differ significantly from each other. Correlation analyses indicated the strongest negative correlation with age occurred with the size judgment span task. Implications of these findings for understanding strategic processing abilities in late life are discussed.