RESEARCH REPORT © 2005 Society for the Study of Addiction doi:10.1111/j.1360-0443.2005.01152.x Addiction, 100, 1270–1279 Blackwell Science, LtdOxford, UKADDAddiction0965-2140© 2005 Society for the Study of Addiction 100 Original Article Alcohol expectancies and peer group drinking behaviour Sander M. Bot et al. Correspondence to: Sander M. Bot Behavioural Science Institute University of Nijmegen PO Box 9104 6500 HE Nijmegen the Netherlands Tel: +31 (0) 24 361 57 87 Fax: +31 (0) 24 361 27 76 E-mail: s.bot@pwo.ru.nl Submitted 16 August 2004; initial review completed 22 October 2004; final version accepted 23 March 2005 RESEARCH REPORT The effects of alcohol expectancies on drinking behaviour in peer groups: observations in a naturalistic setting Sander M. Bot 1 , Rutger C. M. E. Engels 1 & Ronald A. Knibbe 2 Behavioural Science Institute, Radboud University Nijmegen, the Netherlands 1 and Medical Sociology, University of Maastricht, the Netherlands 2 ABSTRACT Aims To study the functionality of alcohol expectancies in predicting drinking behaviour in existing peer groups of young adults in a ‘naturalistic’ setting. Design and setting Young adults were invited to join an experiment with their peer group in a bar annex laboratory. During a ‘break’ of 50 minutes in this experiment, their activities, social behaviour and drinking behaviour were observed with digital video and audio equipment. Participants Twenty-eight peer groups were involved in this study. A peer group consisted of seven to nine people, with relationships ranging from inti- mate relations and close friendships to being acquaintances. A total of 238 par- ticipants were involved. Measurements Information of the drinking behaviour from observations and questionnaire data on alcohol expectancies provide the opportunity to look at how and which expectancies are related to actual drinking patterns. Multiple regression and multi-level analyses were applied. Findings Expectancies on the positive and arousing effects of alcohol con- sumption were related to alcohol consumption in a naturalistic, social drinking situation, in addition to group effects of drinking. Expectancies on the negative and sedative effects of drinking, however, were not related to drinking. Conclusions The findings indicate that among young adults observed in a peer group and naturalistic drinking setting, positive expectancies about the effects of alcohol and expectancies about the effects of alcohol on arousal are related positively to drinking level. KEYWORDS Alcohol expectancies, naturalistic setting, observations. INTRODUCTION Research on alcohol expectancies has become central in theoretical models explaining adolescent and adult involvement in drinking patterns, alcohol misuse and alcohol-related problems (Abrams & Niaura 1987; Leigh 1989). Since Brown et al. (1980) developed the Alcohol Expectancy Questionnaire (AEQ) assessing individual perceptions on a variety of positive alcohol related conse- quences, many studies have focused on the link between alcohol expectancies and drinking habits. In addition, researchers differentiated positive and negative expectan- cies and showed that in both social and problem drinkers, negative expectancies contributed in the prediction of less drinking (e.g. Fromme et al. 1993). An example concern- ing the increasing attention on alcohol expectancies, is a study by George et al. (1995), who tested thoroughly the psychometric properties of an instrument consisting of eight subscales on specific positively (e.g. enhancement, sexual, relaxation) and negatively (e.g. loss of power, loss of control) perceived outcomes of drinking. In line with these studies refining the measurement of alcohol expect- ancies, some others suggested distinguishing between expectancies with regard to the effects of various levels of