Cross-posted at Family Inequality. People don’t know how much
they’re eating. A recent experiment found that people eat more
when the container is larger, even when the portion size is not.
They gave Belgian college students a container of M&Ms and
parked them in front of a TV, with some cover story. The
students were randomly assigned to three groups, medium-
portion/small-container, medium-portion/large-container, and
large-portion/large-container. These were the results: The ones
who got the large container ate more, whether it was full or not
(the difference between the two wasn’t significant). These kinds
of experiments continuously suggest that distractions,
distortions and other apparently irrelevant information and
events routinely have large effects on people’s eating practices
(here’s an extensive review). One infamous study showed that
even people served 14-day-stale popcorn at the movies ate 34%
more when it was served in a large container. In an earlier
popcorn study, researchers found that people