CONTROLLED AND AUTOMATIC FORMS OF MEMORY AND ATTENTION - PROCESS PURITY AND THE UNIQUENESS OF AGE-RELATED INFLUENCES

Estimates of controlled and automatic processes hypothesized to underl ie performance in a memory task and in an attention task were derived for 115 participants from 18 to 78 years of age using the process-diss ociation procedure. Participants also performed speed and neuropsychol ogical tests that were suspected to be negatively related to age. Proc ess estimates showed good reliability (from .76 to .98), and the quali tative distinction between processes was supported by the overall patt ern of correlations among measures. However, only estimated automatic processes exhibited unique variance, as they were either weakly relate d or unrelated both to performance on the other tests and to each othe r. Estimates of the control processes, in contrast, shared considerabl e variance with measures from other tests, and there were no unique, o r independent, age-related effects on these measures. The results high light the need to distinguish between process purity and the uniquenes s of age-related influences in accounting for age differences in cogni tion.