Hosts who want their guests to stay sober should consider their glassware since a study finds that people pour more into squat glasses than into tall ones.Researchers tested 198 college students and 86 bartenders from a large U.S. city and found that the students, even with practice, poured more 20 to 30 percent more liquor into short glasses than tall ones when asked to pour a standard shot of vodka.The bartenders had an average of six years of experience, but they also tended to overpour into short glasses.The research team suggests buying tall thin glasses for social occasions or glasses with the level marked on them. Hosts should also consider that when people are drinking from short squat glasses two drinks is actually likely to be two and one half.The study was published in the British Medical Journal.