The authors conducted experiments with offering free food in public areas, varying the size of the product unit and the size of the serving utensil. In one experiment, researchers observed a mixing bowl of M&M's in the lobby of an apartment building, setting the serving spoon size at variance. The results demonstrate an identifiable unit bias, as passersby tended to take a single unit or spoonful of food without consideration for its size or quantity. As tests were conducted both within eyesight of others and in a more discreet location, the bias in favor of consuming a single unit cannot be attributed solely to the avoidance of perceptible gluttony.
"It is more than just people being afraid of appearing greedy," state the authors. "We have a culturally enforced 'consumption norm,' which promotes both the tendency to complete eating a unit and the idea that a single unit is the proper amount to eat." The concept of unit bias helps explain how environmental differences in portions and package sizes impact overall consumption and may provide a foundation for a better understanding of the psychology of obesity.
This study is published in the June issue of Psychological Science. Media wishing to receive a PDF of this article please contact JournalNews@bos.blackwellpublishing.net
The flagship journal of the Association for Psychological Science (previously the American Psychological Society), Psychological Science publishes authoritative articles of interest across all of psychological science, including brain and behavior, clinical science, cognition, learning and memory, social psychology, and developmental psychology.
Andrew Geier is a Doctoral Candidate in experimental psychology at the University of Pennsylvania. He is available for media questions.
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Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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