Ever order a drink, and feel stiffed on the pour? Well, before you bother the bartender, take a closer look at the size of your glass. "So people will generally perceive there to be less in larger containers, than in smaller ones." Theresa Marteau, a behavioral scientist at the University of Cambridge, in England.
She and her colleagues had analyzed how larger portions—and larger plates—lure us into eating more food. And they wondered: could the same be true for alcohol?
So the researchers convinced the staff at a local bar to run an experiment: every two weeks, for four months, they'd rotate the bar's wine glasses from the standard 300 milliliter size, to either slightly larger—370 milliliters, or slightly smaller—250 milliliters. And see how the size of the glass affected patrons' drinking habits, even though the pour, the volume of alcoholic beverage, was unchanged.
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Turns out, serving wine in smaller glasses had no measurable effect. But the large glasses boosted wine sales 10 percent—even after controlling for day of the week, temperature, holidays and so on. The reason? "When the wine, the same volume, is being served in a larger glass, then people are probably perceiving they've got less in there." Which, she says, means they might drink more, assuming they haven't hit their nightly limit. Or, they might just feel less satisfied with the pour, and buy another round. The study appears in the journal BMC Public Health. [Rachel Pechey et al., Does wine glass size influence sales for on-site consumption? A multiple treatment reversal design]
Aside from altering her own habits—"I do use smaller glasses, yes"—Marteau says that, if subsequent studies confirm this effect, public health officials might consider mandating a certain average glass size. "Specifying the size, the maximum size in which wine can be sold could be a measure that's introduced to reduce the overconsumption of alcohol that seems to be cued by the glass size." Until that happens, the bar in the study now always serves its wine in the larger glasses.
—Christopher Intagliata
[The above text is a transcript of this podcast.]
