Laura Smarandescu of Iowa State and Brian Wansink of Cornell University in Ithaca, N.Y., said they recruited 73 students of legal drinking age, who drank at least one glass of wine a week.
The students were brought to several stations and were asked to pour themselves a normal serving of wine. At each of these stations, the researchers manipulated environmental cues to measure their effects such as supplying different sizes and widths of wine glasses.
To examine the visual effects of color contrast, there was either low contrast between the wine and the glass -- white wine in a clear glass -- or high contrast such as red wine in a clear glass.
The study, published in Substance Use and Misuse, found when glasses were wider, participants poured 11.9 percent more wine. They poured 12.2 percent more wine when holding their glasses, compared with pouring into glasses placed on a table. When there was low contrast between the glass and the wine such as white wine in a clear glass, participants poured 9.2 percent more wine than when there was high contrast such as red wine in a clear glass.