Selective influence of working memory load on exceptionally slow reaction times

Nitzan Shahar, Andrei R. Teodorescu, Marius Usher, Maayan Pereg, Nachshon Meiran

Research output: Contribution to journalArticlepeer-review


The rate of exceptionally slow reaction times (RTs), described by the long tail of the RT distribution, was found to be amplified in a variety of special populations with cognitive deficits (e.g., early-stage Alzheimer's disease, attention-deficit/hyperactivity disorder, low intelligence, elderly). Previous individual differences studies found high correlations between working memory (WM) and parameters that characterize the magnitude of the long-RT tail. However, the causal direction remains unknown. In 3 choice-reaction task experiments, we examined this relationship by directly manipulating WM availability. In Experiment 1, the stimulus-response rules were either arbitrary (WM demanding) or nonarbitrary. In Experiment 2, the arbitrary rules were either novel (demanding) or practiced. In Experiment 3, WM was loaded with either declarative (stimulus-stimulus) or procedural (stimulus-response) arbitrary rules. Using an ex-Gaussian model fitting, we found across all experiments that WM demands uniquely influenced the τ parameter, mostly responsible for the long-RT distribution tail. Evidence accumulation modeling of the choice process indicated that WM load had little influence on the decision process itself and primarily affected the duration of an exponentially distributed nondecision component, assumed to reflect the process of rule retrieval. Theoretical interpretations and implications are discussed.

Original languageEnglish
Pages (from-to)1837-1860
Number of pages24
JournalJournal of Experimental Psychology: General
Issue number5
StatePublished - 2014
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2014 American Psychological Association.


  • Choice-reaction task
  • Evidence accumulation modeling
  • Ex-Gaussian distribution
  • Intraindividual variability
  • Working memory

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • General Psychology
  • Developmental Neuroscience


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