Age-related elevations in intraindividual variability on associative memory tasks

ABSTRACT

Age-related elevations in cognitive intraindividual variability (IIV) have been linked to reduced executive control associated with decline in frontal lobe function. However, the theoretical conceptualization of IIV in cognitive aging may be constrained by limited study of the extent to which age-related elevations in IIV may be observed on cognitive processes sensitive to aging, but not primarily reliant on frontal systems. To address this empirical gap, the present study investigated age-related differences in IIV on two associative memory tasks. Older adults showed elevated IIV on both tasks compared to younger adults. Elevated IIV was correlated with slowed response speed across both groups and tasks; IIV-accuracy correlations were mixed. Findings suggest that IIV may reflect age-related decline in distributed neural networks, including medial temporal regions, in addition to frontal systems dysfunction.

Keywords:

• Associative memory
• Aging
• Intraindividual variability
• Within-person variability

This work was supported by a postdoctoral fellowship from the Alzheimer Society of Canada and the Alzheimer Society of British Columbia to Susan Vandermorris, by a grant from the Alzheimer’s Society of Canada (#07-89) to Angela Troyer and Kelly Murphy, and through funding from the Morris Goldenberg Medical Research Endowment. We thank Nicole Anderson for computer programming, Nicole D’Souza and Angelina Polsinelli for assistance with data collection, and Andrea Maione for assistance with data management.

Notes

¹ In this paper, IIV will be used to represent within-person, within-task, trial-to-trial variability, unless otherwise specified.