4 Comparing Learning Process Variables to Memory Performance and Salivary Cortisol: Is Gender a Moderator of Relationships?

Abstract

Objective:Learning process variables such as the serial position effect and learning ratio (LR) are predictive of cognitive decline and dementia. Gender differences on memory measures are well documented, but there is inconsistent evidence for gender effects on learning process variables. In the present study, we examined the relationship of serial position and LR to memory performance and to cortisol levels, considering gender as a potential moderator.Participants and Methods:Data were taken from a deidentified dataset of a study on stress and aging in which 123 healthy community-dwelling adults over age 50 completed various assessments. Our analyses included 100 participants (56% female, 93% white, Mage 60.65, Meducation 15.22 years) who completed all measures of interest. LR, primacy effect, and recency effect were calculated from the learning trials of the Auditory Verbal Learning Test (AVLT). Additional memory measures included recall measures from the AVLT and from the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). AUC cortisol was calculated from salivary cortisol samples taken across 6 time points in the study.Results:Women performed better than men on LR, primacy, and traditional memory measures (ps=<.001 to .018) but not on recency (p=.40). LR was moderately correlated with primacy (r=.481, p<.001) and weakly correlated with recency (r=.271, p=.008), after controlling for age, gender, and education. After controlling for age, gender, and education, better LR was related to better memory performance across all measures (rs=.276-.693, ps= <.001-.007) and better recency was related to better performance on all memory measures (rs=.212-.396, ps=<.001-.038). Better primacy was related to better AVLT immediate and delayed recall and RBANS Immediate Memory Index (rs=.326-.532, p<.001) but not RBANS delayed (r=.115, p=.263).Hierarchical linear regressions were conducted to examine gender as a moderator of relationships between learning process variables and memory performance, after accounting for age, gender, and education. There were no gender by LR (ps=.349-.830) or gender by primacy interactions (ps=.124-.671). There was an interaction between gender and recency on AVLT memory measures (ps=.006-.022), but not on RBANS measures (ps=.076-.745). For men, higher recency was related to higher AVLT immediate and delayed recall (rs=.501-.541, ps<.001), but not for women (rs=.-.029-.020, ps=.839-.888), after controlling for age and education. The relationship of AUC salivary cortisol to learning process measures was also moderated by gender (LR/gender interaction p=.055; primacy/gender interaction p=.047; but not recency/gender p=.79). Interestingly, for women, higher cortisol was related to higher LR (r=.16) and higher primacy (r=.36), while for men, it was related to lower LR (r=-.22) and not to primacy (r=-.05). Cortisol was not related to recency (rs=-.04 to -.07).Conclusions:Women performed better on LR and primacy, as well as on other traditional memory variables, but gender did not appear to differentially impact the relationship of LR or primacy to memory outcomes. Findings suggest some differential relationships of recency to memory outcomes by gender. Results also suggested potential gender differences in the relationship of cortisol to learning process variables, but further study is necessary, especially with samples of individuals with memory impairment.