Simultaneous-successive processing across the life-span: a cross-sectional examination of stability and proficiency.

A cross-sectional comparison of elderly (n = 70, M = 71.55 years) and young adults (n = 157, M = 22.85) was performed employing a battery of tests sensitive to simultaneous-successive cognitive processing as described by the Luria-Das model. Factor analytic data were supportive of the basic stability and generalizability of this model over the life-span, i.e., a two-factor solution for the various cognitive tasks was obtained for both groups. Differences in the salient factor loadings across the groups are discussed, as are quantitative deficits in performance by the elderly. Covarying age and education, analyses of placement differences within the elderly sample suggested a greater deficit in simultaneous processing scores as a function of restrictiveness of placement.