Does meal duration predict amount consumed in lone diners? An evaluation of the time-extension hypothesis

The time-extension hypothesis has been proposed to describe why social facilitation (the tendency for presence of co-eaters to increase the amount eaten) occurs amongst groups of diners. However, it is possible that time-extension could increase the amount eaten in the absence of social effects. Therefore, the aim of this study was to assess whether prolonged exposure to a food environment without social interaction could increase consumption. Lone diners (n = 141) were observed eating in a fast food environment. The items consumed, meal duration, estimated demographics (sex, weight status and age) and whether or not the participant was reading were recorded unobtrusively. Lone diners who were reading spent longer eating (M = 17.36; SD = 8.23) than those who were not (M = 8.88; SD = 5.47), but energy intake was less than 200 kJ greater, and not overall related to time spent eating. The fact that time-extension did not alter the amount eaten in lone diners is discussed in the context of previous studies and the theory of social facilitation.