Shape of glass and amount of alcohol poured: comparative study of effect of practice and concentration.

Objective: To determine whether people pour different amounts into short, wide glasses than into tall, slender ones. Design: College students practiced pouring alcohol into a standard glass before pouring into larger glasses; bartenders poured alcohol for four mixed drinks either with no instructions or after being told to take their time. Setting: University town and large city, United States. Participants: 198 college students and 86 bartenders. Main outcome measures: Volume of alcohol poured into short, wide and tall, slender glasses. Results: Aiming to pour a "shot" of alcohol (1.5 ounces, 44.3 ml), both students and bartenders poured more into short, wide glasses than into tall slender glasses (46.1 ml v 44.7 ml and 54.6 ml v 46.4 ml, respectively). Practice reduced the tendency to overpour, but not for short, wide glasses. Despite an average of six years of experience, bartenders poured 20.5% more into short, wide glasses than tall, slender ones; paying careful attention reduced but did not eliminate the effect. Conclusions: To avoid overpouring, use tall, narrow glasses or ones on which the alcohol level is premarked. To avoid underestimating the amount of alcohol consumed, studies using self reports of standard drinks should ask about the shape of the glass. (PsycINFO Database Record (c) 2009 APA, all rights reserved) (from the journal abstract)