K. Warner Schaie, Sherry L. Willis and Sara Pennak The Pennsylvania State University

1. Cohort Differences in Level And Rate of Change in Cognition for Third Age Elders: Seattle Longitudinal Study K. Warner Schaie, Sherry L. Willis and Sara Pennak The Pennsylvania State University

2. Research in the Seattle Longitudinal Study, Data from Which Are Reported here, has been Supported by Grants from:

3. Overview: • Cohort Differences in Cognitive Level and Slope over the Third Age (60 to 74 years) • Prior Research has focused on Cohort differences in Level • Studied for Cohorts born in 1896, 1903, 1910, 1917 and 1924 (Total N = 455) • Implications for Retirement Decisions

4. Variables • Verbal Ability (Comprehension of Oral and Written Information • Spatial Orientation (Ability to Mentally Rotate Objects in Two Dimensions) • Word Fluency (Recall of Words for Oral or Written Communication)

5. Examples of Test Items Verbal Ability OLD a. Good b. Ancient c. Wise d. Respected Spatial Orientation

6. Examples of Test Items Word Fluency Study participants write words beginning with a specific letter for a 5 minute period Example: Letter ‘P” “pretty” “pursue” “partition”

7. Age Changes from 60 to 74 by Cohortfor Verbal Ability

8. Age Changes from 60 to 74 by Cohortfor Spatial Orientation

9. Age Changes from 60 to 74 by Cohortfor Word Fluency

10. Summary of Cohort Differences in Level and Slope • Verbal Ability • Level Increases across all Cohorts • Slope Decreases for Recent Cohorts • Spatial Orientation • Level Increases across all Cohorts • Slope Decreases from Age 60 to 67 for Three Most Recent Cohorts • Word Fluency • Minimal Cohort differences in Level at Age 60 • Slope Decreases Dramatically across Cohorts

11. Patterns of Change Across Cohorts • Categorization of Individuals by Change Status: • Stable across 14 years • Reliable Decline across 14 years • Reliable Gain across 14 years • Baseline Performance Level • Cohort Differences in Change Status & Baseline Level

12. Proportions Declining, Gaining and Remaining Stable from Age 60 to 74 for Verbal Ability

13. Proportions Declining, Gaining and Remaining Stable from Age 60 to 74 for Spatial Orientation

14. Proportions Declining, Gaining and Remaining Stable from Age 60 to 74 for Word Fluency

15. Summary of Cohort Differences in Cognitive Change Patterns • Verbal Ability • Both High and Low Baseline Groups Decrease in Decliners and Increase in Stables across Cohorts • Spatial Orientation • Only High Baseline Group Decreases in Decliners and Increases in Stables across Cohorts • Word Fluency • No Cohort Differences in Change Patterns

16. Conclusions and Implications • Marked Increases across Cohorts in Performance Level During Third Age (60 to 74 Years) • Recent Cohorts Function at Higher Cognitive Levels during the Third Age • Cohort Differences in Slope Vary by Ability • Decrease in slope across cohorts is most systematic for Crystallized Intelligence (Verbal) and Executive Functioning (Fluency) • Only the High Function Group within Recent Cohorts Decreased in Slope for Fluid Intelligence (Spatial Orientation) • Maintenance of Crystallized and Executive Abilities Supports Established Life Tasks and Occupational Pursuits • Maintenance of Fluid Intelligence Supports Learning New Information

17. Implications for Public Policy on Retirement • Increases in Cognitive Level across Cohorts Persist to Age 74 • Recent Cohorts have Cognitive Capacity to Continue Occupational Pursuits to Later Ages • Decreases across Cohorts in Slope of Cognitive Decline • The Slowing of Decline in Crystallized Intelligence and Executive Functioning Supports Possibility of Maintaining Occupational Pursuits Across the Third Age • These Cohort Findings Support the Progressive Delay in Eligibility Age of Retirement Benefits