Buffering stress in cognitive aging: the moderating role of positive emotions on trait-level stress reactivity and negative emotions in middle-aged and older adults

Introduction This study examined the moderating role of positive emotion in the relationship between trait-like stress reactivity and negative emotion, and whether this moderating effect varies by cognitive performance and cognitive decline across nine years. Methods Using data from 2,041 participants in the Midlife in the United States (MIDUS) study (mean age = 65.52 years), hierarchical regression models were conducted to predict negative emotion from trait-like stress reactivity, positive emotion, and their interaction, controlling for age, gender, years of education, depressed mood, and neuroticism. Simple slope analyses were conducted to test the direction of significant interactions. Analyses were repeated within subgroups of cognitive performance and cognitive decline across 9 years. Results The interaction between positive emotion and trait-like stress reactivity was significant, with higher positive emotion associated with a weaker relationship between stress reactivity and negative emotion. This moderating effect was observed across low, moderate, and high cognitive performance groups; a three-way interaction further indicated that the moderating effect becomes stronger as cognitive performance increases. For cognitive decline, the moderating effect was significant only among individuals with relatively greater cognitive decline, although the three-way interaction was not significant. Conclusion Positive emotion may buffer the relationship between trait-level stress reactivity and negative emotion across the cognitive performance range, although this moderating effect appears weaker at lower cognitive performance. Findings for cognitive decline were less conclusive, as a subgroup-specific association among participants with greater decline was not confirmed when cognitive decline was analyzed as a continuous moderator.