Alcohol and Complex Functioning

Twenty‐five managers participated in two parallel 6‐hour quasi‐experimental simulations. On placebo treatment days, the subjects received hourly placebo drinks. On alcohol treatment days (order counterbalanced), enough alcohol was provided prior to the fourth hour of simulation participation to attain a breath alcohol level (BAL) of near 0.10. All other drinks contained a placebo beverage. Complex task performance was assessed on five variables derived from complexity theory, comparing performance for three measurement periods: (a) prior to the fourth hour of simulation participation (placebo treatment), (b) during the fourth hour (rising BALs on alcohol treatment days), and (c) during the fifth/sixth hours (falling BALs). Alcohol diminished the participants’ breadth of approach (differentiation). Performance on indicators of strategic functioning (integration) decreased after BALs had begun to fall but not while BALs were rising. The implications for performance of complex tasks under the influence of alcohol and for the applicability of the acute tolerance phenomenon to complex task environments are considered.