Early-life education may help bolster declarative memory in old age, especially for women

Abstract

Although declarative memory declines with age, sex and education might moderate these weaknesses. We investigated effects of sex and education on nonverbal declarative (recognition) memory in 704 older adults (aged 58-98, 0-17 years of education). Items were drawings of real and made-up objects. Age negatively impacted declarative memory, though this age effect was moderated by sex and object-type: it was steeper for males than females, but only for real objects. Education was positively associated with memory, but also interacted with sex and object-type: education benefited women more than men (countering the age effects, especially for women), and remembering real more than made-up objects. The findings suggest that nonverbal memory in older adults is associated negatively with age but positively with education; both effects are modulated by sex, and by whether learning relates to preexisting or new information. The study suggests downstream benefits from education, especially for girls.

Keywords: Aging; declarative memory; education; episodic memory; nonverbal memory; sex differences.

Figure 1:

Examples of the real and novel objects used as stimulus materials for the encoding phase (top two images, in A) and the recognition phase (bottom two images, in B). Note the reminder symbols at the bottom of the screen, which differ between the encoding and recognition phases; see Procedure.

Figure 2:

Performance at recognition memory (d’) as a function of education and sex, controlling for other predictors (i.e., controlling both for main effects and for interactions). In all figures, regression lines represent partial effects, that is, the effects of interest while holding all other continuous predictors constant at their means, and as the average of the effects of interest at different levels of other categorical variables. Shaded bands represent pointwise standard errors (95% confidence intervals are approximately twice the width of standard error bands).

Figure 3:

Performance at recognition memory (d’) as a function of education and object type, controlling for other predictors.

Figure 4:

Performance at recognition memory (d’) as a function of sex and age, controlling for other predictors separately for (A) real objects and (B) novel objects.