Probability Effects on Stimulus Evaluation and Response Processes

William J. Gehring, Gabriele Gratton, Michael G.H. Coles, Emanuel Donchin

Research output: Contribution to journalArticlepeer-review


This study investigated the effects of probability information on response preparation and stimulus evaluation. Eight subjects responded with one hand to the target letter H and with the other to the target letter S. The target letter was surrounded by noise letters that were either the same as or different from the target letter. In 2 conditions, the targets were preceded by a warning stimulus unrelated to the target letter. In 2 other conditions, a warning letter predicted that the same letter or the opposite letter would appear as the imperative stimulus with.80 probability. Correct reaction times were faster and error rates were lower when imperative stimuli confirmed the predictions of the warning stimulus. Probability information affected (a) the preparation of motor responses during the foreperiod, (b) the development of expectancies for a particular target letter, and (c) a process sensitive to the identities of letter stimuli but not to their locations.

Original languageEnglish (US)
Pages (from-to)198-216
Number of pages19
JournalJournal of Experimental Psychology: Human Perception and Performance
Issue number1
StatePublished - Feb 1992
Externally publishedYes

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Arts and Humanities (miscellaneous)
  • Behavioral Neuroscience


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