Psychology of overeating probed

Philadelphia moviegoers given large buckets of stale popcorn described as tasting “terrible” ate 31 percent more than those who received medium buckets of the same unpleasant snack, according to a study.

The study is part of a wealth of research conducted by investigators at the University of Illinois at Urbana-Champaign, which has shown that large portions or packages, proximity to food, short and wide glasses, taste expectations and descriptive names for dishes are all factors in making people eat and drink more.

The research, led by professor Brian Wansink, also determined that consumers are unaware that those factors contribute to the amount they eat and drink.

The people in the Philadelphia audience who munched on the old popcorn weren’t the only ones who proved that larger portions make people eat more.

On his Web site (www.foodpsychology.com), Mr. Wansink describes a study of 161 Chicago moviegoers who were given coupons for free popcorn and a soft drink when they purchased their tickets. They were randomly given either a large or medium container of popcorn.

Mr. Wansink could not be reached for comment, but he has an extensive interview about his research in the current issue of Nutrition Action, a newsletter published by the Center for Science in the Public Interest.

Asked if larger portions make people eat more, Mr. Wansink told CSPI, “Yes … we found out [through the Chicago moviegoers study] that the people who were given big buckets ate roughly 50 percent more than the people who were given smaller buckets.”

An abstract of the study on his Web site says moviegoers who rated the popcorn as “tasting relatively unfavorably ate 61 percent more popcorn if randomly given a large container than a smaller one.”

In a telephone interview yesterday, Jill North, a graduate student at the university who has assisted Mr. Wansink in his research, discussed another study involving secretaries and their candy consumption.

University secretaries were asked to put a dish of chocolate either on their desk or about six feet away from their desk. Each dish had 30 candies, some bowls were clear, while other bowls were opaque.

Each night for four weeks, researchers secretly counted how many chocolates each secretary ate that day and then refilled the bowl with 30 candies.

“The most significant drop [in the number of candies eaten] occurred if the candy was away from a secretary’s desk,” Miss North said.

Mr. Wansink said about nine chocolates a day were eaten if the candy bowl was clear and it was kept on the desk. Consumption dropped to 6 chocolates daily if the candy was in an opaque container.

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