Intraindividual reaction time variability is malleable: feedback- and education-related reductions in variability with age

Douglas D Garrett,Stuart W S Macdonald,Fergus I M Craik

doi:10.3389/fnhum.2012.00101

Abstract

Intraindividual variability (IIV) in trial-to-trial reaction time (RT) is a robust and stable within-person marker of aging. However, it remains unknown whether IIV can be modulated experimentally. In a sample of healthy younger and older adults, we examined the effects of motivation- and performance-based feedback, age, and education level on IIV in a choice RT task (four blocks over 15 min). We found that IIV was reduced with block-by-block feedback, particularly for highly educated older adults. Notably, the baseline difference in IIV levels between this group and the young adults was reduced by 50% by the final testing block, this advantaged older group had improved such that they were statistically indistinguishable from young adults on two of three preceding testing blocks. Our findings confirmed that response IIV is indeed modifiable, within mere minutes of feedback and testing.

Highlights

Moment-to-moment intraindividual variability (IIV) often refers to relatively rapid fluctuations in task performance
There were no significant effects in the young group, suggesting that neither Feedback nor Education had an impact on ISD scores
We were interested in differences in ISD values at, or in relation to, Block 4, as this block represented participants’ final chance at performance after the maximum amount of possible feedback exposure

Summary

Introduction

Moment-to-moment intraindividual variability (IIV) often refers to relatively rapid fluctuations in task performance (see Hultsch et al, 2008; MacDonald et al, 2009a). IIV is effectively a proxy measure representing a host of complex and dynamic influences and processes. Age-based behavioral analyses of the Ex-Gaussian RT distribution suggest that the IIV effect is caused primarily by excessively slow within-person response latencies (West et al, 2002; Williams et al, 2005), possibly a result of momentary lapses in attentional control

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Conclusion