Low and variable correlation between reaction time costs and accuracy costs explained by accumulation models: Meta-analysis and simulations.

C Hedge, G Powell, A Bompas, S Vivian-Griffiths, P Sumner

Research output: Contribution to journalArticlepeer-review


The underpinning assumption of much research on cognitive individual differences (or group differences) is that task performance indexes cognitive ability in that domain. In many tasks performance is measured by differences (costs) between conditions, which are widely assumed to index a psychological process of interest rather than extraneous factors such as speed–accuracy trade-offs (e.g., Stroop, implicit association task, lexical decision, antisaccade, Simon, Navon, flanker, and task switching). Relatedly, reaction time (RT) costs or error costs are interpreted similarly and used interchangeably in the literature. All of this assumes a strong correlation between RT-costs and error-costs from the same psychological effect. We conducted a meta-analysis to test this, with 114 effects across a range of well-known tasks. Counterintuitively, we found a general pattern of weak, and often no, association between RT and error costs (mean r = .17, range −.45 to .78). This general problem is accounted for by the theoretical framework of evidence accumulation models, which capture individual differences in (at least) 2 distinct ways. Differences affecting accumulation rate produce positive correlation. But this is cancelled out if individuals also differ in response threshold, which produces negative correlations. In the models, subtractions between conditions do not isolate processing costs from caution. To demonstrate the explanatory power of synthesizing the traditional subtraction method within a broader decision model framework, we confirm 2 predictions with new data. Thus, using error costs or RT costs is more than a pragmatic choice; the decision carries theoretical consequence that can be understood through the accumulation model framework.
Original languageEnglish
Pages (from-to)1200-1227
JournalPsychological Bulletin
Issue number11
Publication statusPublished - 27 Sept 2018

Bibliographical note

This article has been published under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/),which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Copyright for this article is retained by the author(s). Author(s) grant(s) the American Psychological Association the exclusive right to publish the article and identify itself as the original publisher

Funding: This work was supported by a grant from the ESRC (ES/K002325/1);and by the Wellcome Trust (104943/Z/14/Z).


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