EXTROVERSION AND ALCOHOL - EYSENCKS DRUG POSTULATE REVISITED

Within the framework of Eysenck's drug postulate alcohol is frequently used as an example for a depressant drug that should shift a person's position on the extraversion-introversion axis in the direction of lo wer arousability. However, only little experimental evidence for diffe rential effects of alcohol on extraverts and introverts appears to exi st. Therefore, a placebo-controlled study was designed to investigate the effects of 0.65 g/kg alcohol on temporal discrimination, time esti mation, reaction time, movement time, critical flicker fusion frequenc y (CFF), as well as feelings of activity, alertness, drowsiness, joyfu lness, and relaxation in introverts and extraverts. While a main effec t of alcohol could be shown for temporal discrimination (p < 0.05), re action time (p < 0.05), CFF (p = 0.01), and feelings of alertness (p < 0.001) and joyfulness (p < 0.01), significant interactive effects of alcohol and extraversion were only found for time estimation (p < 0.00 1) and feelings of relaxation (p < 0.01). Extraversion-related differe nces in movement time (p = 0.05) proved to be insensitive to alcohol. Results are discussed with regard to the pharmacological profile of al cohol and the validity of the drug postulate.