Higher intraindividual variability is associated with more forgetting and dedifferentiated memory functions in old age

Abstract

a b s t r a c tIntraindividual trial-to-trial reaction time (RT) variability is commonly found to be higher in clinical populations or life periods that are associated with impaired cognition. In the present study, higher within-person trial-to-trial RT variability in a perceptual speed task is related to more forgetting and dedifferentiation of memory functions in older adults (aged 60-71 years). More specifically, our study showed that individuals in a high-variability group (n = 175) forgot more memory scenes over a 1-week retention interval than individuals in the low-variability group (n = 174). In contrast, slower RT speed was associated with poorer episodic memory in general, but unrelated to the amount of forgetting. Moreover, results from multiple group latent factor analyses showed that episodic memory and working memory functions were more highly correlated in the high-variability (r = .63) than in the low-variability (r = .25) group. Given that deficits in dopamine (DA) modulation may underlie increases in RT variability, the present findings are in line with (i) recent animal studies implicating DA in long-term episodic memory consolidation and (ii) neurocomputational work linking DA modulation of performance variability to dedifferentiation of cognitive functions in old age.

Intraindividual reaction time variability predicts prospective memory failures in older adults

“…These results both suggest that older adults who are more variable are more likely to fail to detect a target, whether this is a prospective memory cue or a visual search target. Similarly, the findings are consistent with research identifying relationships in older adults between IIV and errors on other tasks that may relate to everyday functioning (Bunce et al, 2012;Burton et al, 2009;Papenberg et al, 2011).…”

Dopaminergic Gene Polymorphisms Affect Long-term Forgetting in Old Age: Further Support for the Magnification Hypothesis

“…In a recent study, we showed that older adults who fluctuated more from trial to trial in their RTs forgot more information after 1 week (Papenberg et al, 2011). Neurocomputational simulations (Li, Naveh-Benjamin, & Lindenberger, 2005;Li & Sikström, 2002;Li, Lindenberger, & Sikström, 2001) suggest that suboptimal DA modulation results in a lower signal-to-noise ratio and less distinctive neural representations, which then lead to increased intraindividual variability and lower memory performance at the behavioral level.…”

Does within-person variability predict errors in healthy adults aged 18–90?

“…In older adults, increased variability has been associated with poorer memory performance (MacDonald, Nyberg, Sandblom, Fischer, & Backman, 2008) and forgetting rates over a one-week period (Papenberg et al, 2011). Across old and young however, increased variability was moderately associated with poorer memory in older adults, but in younger adults, the opposite was found (Vandermorris, Murphy, & Troyer, 2013).…”