Psychomotor Performance Under Alcohol and Under Caffeine: Expectancy and Pharmacological Effects

Mark T. Fillmore, M. Vogel-Sprott

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


This experiment tested the hypothesis that Ss' expectancies about drug effects on psychomotor performance would predict their responses to drug and placebo. Forty male undergraduates were assigned to 1 of 5 treatments: alcohol (0.56 g/kg), placebo alcohol, caffeine (2.93 mg/kg), placebo caffeine, or no treatment. Groups received preliminary training on a pursuit rotor task before rating the effect that caffeine or alcohol was expected to have on their performance. Ss' performance was measured under the treatments and showed impairment under alcohol and improvement under caffeine. However, regardless of whether they received a drug or placebo, those who expected the most impairment performed the most poorly. Results indicate the importance of expectancies in understanding individual differences in response to drugs and placebos.

Original languageEnglish
Pages (from-to)319-327
Number of pages9
JournalExperimental and Clinical Psychopharmacology
Issue number4
StatePublished - Nov 1994

ASJC Scopus subject areas

  • Pharmacology
  • Psychiatry and Mental health
  • Pharmacology (medical)


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