A new study offers evidence that how much people choose to eat is in part determined by cues taken from their surroundings.
The concept is called "unit bias," the tendency to think of a single unit of food, such as a bottle, can, or plateful, as an appropriate amount, even though such units can vary greatly in size.
The idea is not a new one, and experts have previously pointed to the supersizing of fast food and restaurant portions as one explanation for the rise in obesity.
But researchers found striking evidence to support it when they left a bowl of M&M's in the lobby of an apartment building and varied the size of the scoop people could use to take some. Sometimes the scoop could hold a quarter-cup, and other times only a tablespoon. People consistently took more M&M's when the bigger scoop was provided.
A similar experiment was done with a bowl containing either 80 small Tootsie Rolls or 20 big ones. Once again, people consistently removed more, by weight, when the Tootsie Rolls were offered in the larger packages.
