Stop being neutral: Simon takes control!

Daniela Aisenberg, Avishai Henik

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


The Simon task is one of the well known tasks that recruit cognitive control. The Simon effect, the reaction time (RT) difference between congruent and incongruent stimuli, has been commonly discussed as interference based. Nevertheless, in recent years some studies have referred to the facilitation component of the task. In the current research we measured effects of cognitive control by conducting sequential analysis and adding neutral conditions. Two neutral stimuli were employed in order to examine their effect and their validity as neutrals. It was found that presentation of Simon stimuli on the central meridian at the top or bottom of a screen (but not at the centre of the screen) created a valid neutral condition. Facilitation as well as interference effects were found. Adding a nonconflict condition modulated cognitive control independently of sequential effects. Namely, the Simon effect increased by adding both types of neutrals, but the decrease in the effect after incongruent trials was only present for the vertical neutral block, in which the Simon effect appeared after congruent but not after incongruent trials. We suggest the possibility of two different mechanisms of cognitive control.

Original languageEnglish
Pages (from-to)295-304
Number of pages10
JournalQuarterly Journal of Experimental Psychology
Issue number2
StatePublished - 1 Feb 2012


  • Cognitive control
  • Neutrals
  • Sequential analysis
  • Simon effect

ASJC Scopus subject areas

  • Physiology
  • Neuropsychology and Physiological Psychology
  • Experimental and Cognitive Psychology
  • General Psychology
  • Physiology (medical)


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