FIGURE 20-4 Mean meal duration (solid line) in minutes and the rate of intake (dashed line) in kcal/min, as a function of the number of people present at the meal.

social meals and may in fact decrease with large groups (de Castro and Brewer, 1992). Hence, an aroused state hypothesis cannot explain social facilitation of intake.

Social facilitation might operate by inducing an emotional response, such as increased anxiety or elation, which may produce an increase in intake (Harlow, 1932; Harlow and Yudin, 1933). This hypothesis would predict an increase in self-reported anxiety or elation with meals eaten socially. Indeed, Harlow (1932) observed greater emotionality in rats fed with others than when fed alone. However, this hypothesis, like the increased arousal hypothesis, predicts an increase in the rate of intake. Also, this hypothesis predicts that when eating with a companion, the more emotionally arousing the companion, the more will be eaten. Hence, eating with people well known to the subject and with whom the subject is comfortable, such as family and friends, should produce the least effect on intake. Analyses of the diet diary data again fail to support this hypothesis. Meals were separated according to the type of companion present with the subject: friend, family, spouse, work associate, or other. Average meal sizes for meals eaten with and without each of these companion types and meals eaten alone are presented in Figure 20-5. As shown, contrary to the hypothesis, family and friends had the greatest impact