The Shape of Your Glass Determines How Fast You Drink

You’re at a bar or pub, and you look down and notice that your glass is half full. Or half empty, depending on how you see the world. Would it surprise you to know that this perception of the beer being at the halfway mark in the glass determines to some extent how quickly you finish it and decide to order another round? Would it further surprise you to learn that the very shape of the glass may determine how fast you finish the beer, and how much you drink in an evening?

Those were the conclusions arrived at by a team of researchers at Bristol University’s School of Experimental Psychology, in England. They were studying how fast people drink alcohol, and with good reason; the United Kingdom has one of the highest incidences of binge drinking in the world. One in four Britons are now classified as binge drinkers, a situation that is viewed as a crisis by health authorities and doctors, who point at not only at the damage done to their own health by binge drinkers of alcohol, but the alarming number of fist fights, assaults, rapes, and auto accidents that binge drinkers inflict upon others.

So a research study on the factors that encourage people to drink faster, and thus drink more, is not really the contender for an Ig Nobel Prize that it may appear to be at first glance.

The research

In the study, 160 social drinkers aged 18 to 40 with no known history of alcoholism were monitored as they drank from either a curved glass or a straight-sided glass. The results of the study showed that people drinking from a curved glass tended to consume the contents almost twice as fast as people drinking from a glass with straight sides. Interestingly, this tendency held true whether the liquid in the glasses was beer, or some non-alcoholic drink.

In follow-up research, the same scientists asked the same subjects to look at photographs of glasses of different shapes containing different volumes of liquid. Again, the participants in the study were less able to tell whether the glass was half full when viewing the liquid in a curved glass. The degree of error in assessing when a glass of liquid had reached the halfway point was strongly correlated to the participants’ speed of drinking in the first part of the study. The less accurate their ability to tell when the glass was half full, the faster they drank.

Truths and myths about alcohol and how they’re affected by this research

Many people believe that consuming one or more alcoholic drinks quickly is somehow safer and less intoxicating than drinking them slowly. This is a myth. The thing that determines how intoxicated you become – and thus whether you are sober enough to drive or make sensible decisions, such as whether to go home with the person sitting next to you – is determined by the volume of alcohol you consume, not by the time you take to drink it. Alcohol is metabolized in the system in a “time release” fashion, over a period of time. Thus if you consume four beers in thirty minutes (as binge drinkers tend to do), you’ll still be just as legally drunk at the end of the evening as you would be if you had consumed them over a period of two hours. Intoxication is just what happens when you drink more than one standard unit of alcohol per hour.

That said, drinking the four beers quickly will make you intoxicated more quickly, and thus less capable of handling yourself in a responsible manner more quickly. Here’s where other common myths about alcohol come into play. Coffee, tea, “getting some air,” or even taking a cold shower will not sober you up. Nor will any of these things make you less sleepy, and thus less likely to fall asleep while driving home. Alcohol, although it may feel like a stimulant, is actually the opposite, a depressant; it will slow down your reaction time and make you sleepy.

Other common myths have to do with what is actually in the glass, curved or straight-sided. On average, white wine does not contain less alcohol than red wine. An average pint of beer, a large glass of wine, and a double shot of vodka all contain the same 2.8 units of alcohol, and will make you equally drunk if you consume too many of them. They will also all make you equally fat.

So whether you are concerned with moderating how much alcohol you consume for dietary reasons (trying to lose weight), for social reasons (trying not to embarrass yourself in front of others), or for social responsibility reasons (trying not to injure others as a result of becoming intoxicated), it looks as if you might be better served by ordering your drinks in a straight-sided glass rather than in a curved one. The bartender or waiter may look at you a little funny when you do this, but you’ll end up drinking less, and that’s probably a good thing all around.

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Juliette Siegfried, MPH

Juliette Siegfried, MPH, has been involved in health communications since 1991. Shortly after obtaining her Master of Public Health degree, she began her career at the National Institutes of Health in Bethesda, Maryland. Juliette now lives in Europe, where she launched ServingMed(.)com, a small medical writing and editing business for health professionals all over the world.

Juliette's resume, facebook: juliette.siegfriedmph, linkedin: juliettes, (+31) 683 673 767

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