How shape can alter a person's notion of size has been widely investigated. For instance, triangles are generally perceived to be larger than squares, and horizontal shapes are seen as smaller than vertical objects of identical volume.
Yet research examining the effects of shape on how people determine how much they consume is limited, said Brian Wansink, a professor of marketing and nutritional science at Illinois. To understand the process better, Wansink examined how shape influences teenagers, adults and bartenders who pour beverages into empty glasses.
The results of his study will be published in the December issue of the Journal of Consumer Research.
Wansink, director of the Food & Brand Lab at Illinois, conducted three tests. In the first, he looked at how much juice 97 teenagers poured for themselves during breakfast at a summer camp in New Hampshire. The male and female campers, 12 to 17, with an average age of 15, had come to the camp to learn about nutrition and lose weight. They were taught about dieting and portion control in daily lectures and demonstrations.
Upon entering the cafeteria line for breakfast on the ninth day, the campers were randomly given a tall and short glass of identical capacity in which to pour their orange juice. The tall glass was slightly less than twice the height of the small glass.
The teenagers poured 76.4 percent more orange juice in the short, wide glasses than in the tall glasses (9.7 ounces versus 5.5 ounces). Although the girls poured less juice
Contact: Mark Reutter, Business & Law Editor
University of Illinois at Urbana-Champaign