According to a recent study in the Journal of Consumer Research, both the size and consumption habits of our eating companions can influence our food intake. And contrary to existing research that says you should avoid eating with heavier people who order large portions（份）, it’s the beanpoles with big appetites you really need to avoid.

To test the effect of social influence on eating habits, the researchers conducted two experiments. In the first, 95 undergraduate women were individually invited into a lab to ostensibly（表面上）participate in a study about movie viewership. Before the film began, each woman was asked to help herself to a snack. An actor hired by the researchers grabbed her food first. In her natural state, the actor weighed 105 pounds. But in half the cases she wore a specially designed fat suit which increased her weight to 180 pounds.

Both the fat and thin versions of the actor took a large amount of food. The participants followed suit, taking more food than they normally would have. However, they took significantly more when the actor was thin.

For the second test, in one case the thin actor took two pieces of candy from the snack bowls. In the other case, she took 30 pieces. The results were similar to the first test: the participants followed suit but took significantly more candy when the thin actor took 30 pieces.

The tests show that the social environment is extremely influential when we’re making decisions. If this fellow participant is going to eat more, so will I. Call it the “I’ll have what she’s having” effect. However, we’ll adjust the influence. If an overweight person is having a large portion, I’ll hold back a bit because I see the results of his eating habits. But if a thin person eats a lot, I’ll follow suit. If he can eat much and keep slim, why can’t I?