This study found that for a given snack duration, children consumed more in larger groups than in smaller groups, and the effect strengthened as the snack time lengthened. Snack initiation occurred more rapidly in larger groups, and eating rate was slightly greater in larger groups than in smaller groups. Therefore, we propose that the cumulative effective of beginning to eat sooner and having a marginally greater eating rate over time led to growing differences in the total amount consumed over time. To our knowledge, this study is the first to demonstrate social facilitation of quantity eaten in children.
The study also provides information about the mechanism of the group size effect in children. Our results do not support the time extension hypothesis. Larger group size was actually associated with less social interaction, and there was no difference in snack duration between the smaller and the larger groups. The pattern of our results is better explained by the arousal hypothesis. In the larger group, children initiated eating more rapidly, socialised less, and ate at a slightly faster rate than when they ate in the smaller groups.
There are several limitations to this study. Our sample size was small, and our power may therefore have been limited to detect more subtle effects. We did not have data on the prior meal children consumed at home or when it was consumed, which could have acted as a confounder. However, children's ability to tightly regulate intake in response to caloric preload is limited,34,35
and prior research has shown that social facilitation easily disrupts post‐prandial regulation of intake.21
Finally, we did not collect data regarding the volume of beverages that children consumed. Nonetheless, each child was given the same beverage in both group size conditions in which he or she participated. The fact that beverage type was held constant across group size conditions in the individual child would indicate that beverage type could not act as a confounder of the group size effect.
In summary, our study has demonstrated that when children eat in groups of nine, they eat about 30% more than when in groups of three for the same length of time. The effect seems to be mediated by increased arousal. Preschool‐aged children can be included as also responding to the social facilitation effect of group size on quantity of consumption, although the mechanism of effect seems to be different from in adults, and is open to empirical verification with physiological measures. It is not clear from our study whether large group size increased consumption to “supra‐physiological” levels, or if small group size decreased consumption compared with “typical” intake. However, given that the social facilitation effect can overwhelm satiety mechanisms,21
its potential role in contributing to overconsumption, and thereby increasing overweight risk in children, deserves consideration in future research.
From a clinical perspective, the results provide additional theory‐driven support for frequent recommendations given to families regarding children's eating behaviour. The child who eats inadequate quantities may consume more when eating in a group (eg, with the family at the table for a planned mealtime) than when eating alone, as often occurs when children graze over the course of the day. For the child who overeats, overconsumption may be driven by having meals in overstimulating busy or chaotic environments, as is often the case when eating out, particularly at fast food restaurants. Thus, the results also support recommendations to have mealtimes at home with the family, but for the purpose of providing a calm and peaceful eating environment.
What is already known on this topic
- Familiar behaviours increase when they occur in the presence of others performing the same behaviour. Adults and animals eat more when eating in the presence of a group of others also eating, although prior work has been limited by a lack of control of several important variables.
- It is unknown whether social facilitation operates on quantity of consumption in young children.
What this study adds
- Preschool‐aged children eat about 30% more when eating in a group of nine versus in a group of three.
- The results provide evidence of higher methodological quality for the effect of group size on consumption in humans, and raise questions about the potential relationship between group eating behaviour and childhood obesity.