Seduced by Snacks? No, Not You looks at Professor Brian Wansink’s “quirky experiments in the psychology of overindulgence”:
An appalling example of our mindless approach to eating involved an experiment with tubs of five-day-old popcorn. Moviegoers in a Chicago suburb were given free stale popcorn, some in medium-size buckets, some in large buckets. What was left in the buckets was weighed at the end of the movie. The people with larger buckets ate 53 percent more than people with smaller buckets. And people didn’t eat the popcorn because they liked it, he said. They were driven by hidden persuaders: the distraction of the movie, the sound of other people eating popcorn and the Pavlovian popcorn trigger that is activated when we step into a movie theater.Dr. Wansink is particularly proud of his bottomless soup bowl, which he and some undergraduates devised with insulated tubing, plastic dinnerware and a pot of hot tomato soup rigged to keep the bowl about half full. The idea was to test which would make people stop eating: visual cues, or a feeling of fullness.
People using normal soup bowls ate about nine ounces. The typical bottomless soup bowl diner ate 15 ounces. Some of those ate more than a quart, and didn’t stop until the 20-minute experiment was over. When asked to estimate how many calories they had consumed, both groups thought they had eaten about the same amount, and 113 fewer calories on average than they actually had.