Feeling crowded affects how many calories we consume. Hock and Barchi determined via six studies that “crowding increases calorie consumption. These effects occur because crowding increases distraction, which hampers cognitive thinking and evokes more affective [emotional mental] processing. When consumers process information affectively, they consume more calories.” When people are processing information emotionally, if they're “given a choice between several different options, people select and eat higher-calorie items, but when presented with only one option, people eat more of the same food item.” It’s important to remember that feeling crowded is subjective; one person may feel crowded in a situation but another individual may not, even though both experience exactly the same conditions. Research is therefore necessary to determine if particular users are likely to feel crowded in an environment of interest.
Stefan Hock and Rajesh Barchi. “The Impact of Crowding on Calorie Consumption.” Journal of Consumer Research, in press.