Study: Portion size is all in your mind

Andrew Geier, a doctoral candidate in experimental psychology at the University of Pennsylvania, and colleagues investigated the psychology of consumption and found people have a strong tendency to eat a single unit of food, regardless of the unit's size or caloric value.

The researchers offered free food in public areas, varying the size of the product unit and the size of the serving utensil. The results, they say, demonstrate an identifiable unit bias, with passersby taking a single spoonful of food without consideration for its size or quantity.

Since the experiment was conducted both within eyesight of others and in a more discreet location, the researchers say bias in favor of consuming a single unit cannot be attributed solely to the avoidance of perceptible gluttony.

They said the concept of unit bias helps explain how environmental differences in portion and package sizes impact overall consumption and might lead to a better understanding of the psychology of obesity.

The study appears in the journal Psychological Science.

Copyright 2006 by United Press International