The long term objective of this research is to contribute to understanding about the nature and causes of cognitive change that occur during normal adulthood. The more immediate objective of this project is to fill the gap in knowledge about cognition in one specific age group, those over 80. The research is designed 1) to describe cognitive functioning in the very old and 2) to identify key variables that may contribute to growth, decline, and stability of cognitive performance in late adulthood. Males and females from two age groups (60-70 and 80-90) and four educational backgrounds (less than HS; HS; BA and equal to MS) will be included in the study. Subjects will be assessed on a variety of measures designed to comprehensively examine cognitive function and factors hypothesized to mediate cognitive performance. In addition, subjects will be interviewed about their cognitive life histories.