Trajectories of episodic memory in midlife: Historical change from a cross-country perspective.

According to the Flynn effect, performance on cognitive ability tests has improved over the past decades. However, we know very little about whether such historical improvements generalize to middle-aged adults (aged 45-65) and differ across nations. We used harmonized data on episodic memory from nationally representative longitudinal panel surveys across a total of 16 countries (United States, Mexico, China, England, and countries in Continental, Mediterranean, and Nordic Europe). We compared historical change in age-related trajectories of episodic memory among middle-aged adults. Our sample included 117,231 participants who provided 330,390 observations. Longitudinal multilevel regression models revealed that today's middle-aged adults in the United States perform worse on episodic memory tests than their peers in the past. By contrast, today's middle-aged adults in most other countries perform better on these tests than their peers in the past. However, later-born cohorts of U.S. and Chinese middle-aged adults experienced less steep within-person decrements-or even increments-in episodic memory than earlier born cohorts. Historical change trends persisted when controlling for sociodemographic factors, as well as for indicators of physical and mental health. Differences in episodic memory by gender and education became smaller over historical time across all nations. Our findings suggest that countries differ considerably in episodic memory performance, by more than half a standard deviation, and in the direction and size of how midlife episodic memory trajectories have changed over historical time. Further factors related to historical changes in midlife episodic memory need to be identified by future research. (PsycInfo Database Record (c) 2024 APA, all rights reserved).