Cognitive engagement and cognitive aging: is openness protective?

Abstract

The purpose of this study was to examine whether openness to experience is related to longitudinal change in cognitive performance across advancing age. Participants were 857 individuals from the Swedish Adoption/Twin Study of Aging (SATSA). Factors for 5 cognitive domains were created, including verbal ability, spatial ability, memory, processing speed, and a global score, g. Latent growth curve models were used to assess level and longitudinal trajectories of cognitive performance. It was hypothesized that individuals who endorsed higher levels of openness would have higher cognitive test scores and lesser rates of cognitive decline. As predicted, higher openness to experience was associated with significantly higher performance across all cognitive tests for both men and women even after adjusting for education, cardiovascular disease, and activities of daily living. Openness, however, was not predictive of differences in the trajectories of cognitive performance over age.

Figure 1

Linear latent growth curve with covariate openness to experience and a control covariate. The squares represent observed, or measured, variables, whereas the circles denote latent variables; single-headed arrows represent regression coefficients, and double-headed arrows denote covariation. The triangle represents a unit constant that allows for the estimation of means; the circles within squares represent data that are potentially available for an individual participant at some but not necessarily all time points. r_cso = correlation between the slope and the covariate openness; r_csc = correlation between the slope and the control covariate; M_co = mean of the covariate openness; M_cc = mean of the control covariate; M_i = mean of the intercept; M_s = mean of the slope; r_cio = correlation between the intercept and openness; r_cic = correlation between the control covariate and the intercept; r_is = correlation between the slope and the intercept; Openness* = standardized score of the covariate openness; Covariate* = standardized score of the control variable; I* = standardized score for the intercept; S* = standardized score for the slope; D_co =deviation from the covariate openness mean; D_cc = deviation from the control covariate mean; D_i = deviation from the intercept; D_s = deviation from the slope; I = intercept; S = slope; B1-B4 = age basis coefficients; IPT1-IPT6 = cognition scores at each time point; u₀-u₄ = random components from the cognition scores; u = the constant deviation from the cognition scores (Adapted from Charles, Reynolds, & Gatz, 2001).

Figure 2

Univariate dual change score model. Openness to experience is modeled independently (Y). Error variance (σ_u) is fixed to be constant at every age; α reflects constant change due to the slope factor y_s; β reflects proportional change. The model estimates a latent intercept (y_o) and slope (y_s), mean intercept (μ_o) and mean slope (μ_s), as well as variation around the mean intercept and slope (σ_o and σ_s). The y_o* and y_s* variables reflect the standardized scores of y_o and y_s. The ρ_os parameter is the correlation between initial score and rate of change.

Figure 3

Higher openness scores predicted better performance in the verbal domain for males (3a) and females (3b), controlling for education, ADLs, and CVD. Note. High Openness = 1 standard deviation above the mean, Low Openness = 1 standard deviation below the mean.

Figure 4

Higher openness scores predicted better performance in the spatial domain for males (4a) and females (4b), controlling for education, ADLs, and CVD. Note. High Openness = 1 standard deviation above the mean, Low Openness = 1 standard deviation below the mean.

Figure 5

Higher openness scores predicted better performance in the memory domain for males (5a) and females (5b), controlling for education, ADLs, and CVD. Note. High Openness = 1 standard deviation above the mean, Low Openness = 1 standard deviation below the mean.

Figure 6

Higher openness scores predicted better performance in the speed domain for males (6a) and females (6b), controlling for education, ADLs, and CVD. Note. High Openness = 1 standard deviation above the mean, Low Openness = 1 standard deviation below the mean.

Figure 7

Higher openness scores predicted better performance in global “g” performance for males (7a) and females (7b), controlling for education, ADLs, and CVD. Note. High Openness = 1 standard deviation above the mean, Low Openness = 1 standard deviation below the mean.

Figure 8

Longitudinal openness trajectories by sex.