Expectancy effects in caffeine research.
The impact of expectancy on the experience of caffeine-related symptoms was investigated by randomly assigning subjects to an expectancy or nonexpectancy instructional condition. Subjects were administered the State-Trait Anxiety Inventory and a Symptom Questionnaire prior to and 45 minutes after receiving their designated instructional set and ingesting a cellulose-filled gelatin capsule which ostensibly was filled with caffeine. Results revealed that a significant expectancy effect existed on five Symptom Questionnaire items.
Christensen
L
L
College of Liberal Arts, Texas A & M University, College Station 77843-4235.
White
B
B
Krietsch
K
K
Steele
G
G
D000328:Adult; D001143:Arousal / Q000187:drug effects*; D002110:Caffeine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D010555:Personality Inventory; D012718:Set, Psychology
D002110:Caffeine