C. Peter Herman’s research while affiliated with University of Toronto and other places

Social modeling is a powerful influence on people's food intake: When there is a clear and consistent norm, people eat more when eating with someone who eats a lot and eat less when eating with someone who eats only a little. In three studies, the present research examined how clear versus ambiguous social-normative information influences the modeling of food-related decisions. Using a novel online decision-making paradigm, female participants (total N = 1042) were provided with information about how many cookies previous participants had supposedly selected (no information was provided in the control condition), and then decided how many cookies they would choose for a snack. When there was a clear and consistent norm, the typical social modeling effect was observed. When there was a small number of “dissenters” whose responses conflicted with the norm set by the majority, participants' cookie selection still conformed to the behaviour of the majority (Studies 1 and 2). It was only when the behaviour of the previous participants was highly ambiguous that participants behaved as if they had been given no normative information (Study 3). By demonstrating that, except in extreme cases, people use the available information to discern a social norm that influences their behaviour, these findings highlight the power of social norms related to food-related decisions.

Defining and measuring such qualities as restrained eating or dieting may require more than simply administering questionnaires and assuming that we are identifying the population that we wish to study. Different questionnaires may identify different types of restrained eaters, and even deciding what restrained eating consists of is a complicated endeavor. We discuss how to define and measure restrained eating, specifying key attributes, and acknowledging the problems inherent in relying on self-report instruments. We conclude that given the difficulties in defining such constructs as restrained eating, we need to specify more clearly exactly what our research questions are, in order to be sure that we are identifying the populations with the attributes necessary to answer those questions.

The Theory of Normal Eating suggests that how much others eat sets an upper limit for how much it is appropriate to eat. This study tested the hypothesis that restrained eaters, who typically eat less than they want to, would be more responsive to a high-intake norm than would unrestrained eaters. Data were combined from 8 experimental studies (total N = 735 female participants; 305 restrained eaters, 430 unrestrained eaters). Each study: (a) included a low-intake norm, a high-intake norm, and a no-norm control condition; (b) measured participants’ food intake; and (c) included the Restraint Scale as a measure of dietary restraint. There were no differences between restrained unrestrained eaters in the no-norm control condition or in the magnitude of the inhibition effect (i.e., the difference between the low-intake norm condition and the control condition). There was, however, a restraint difference in the magnitude of the augmentation effect (i.e., the difference between the high-intake norm condition and the control condition). Restrained eaters showed a larger augmentation effect (d = 0.58; 95% CI = 0.29, 0.87) than did unrestrained eaters (d = 0.20; 95% CI = −0.05, 0.45). Social norms provide an upper limit for acceptable food intake, with high-intake norms permitting (but not requiring) individuals to indulge themselves. The fact that restrained eaters were more responsive to the high-intake norm than were unrestrained eaters suggests that the high-intake norm gives restrained eaters permission to indulge when they typically eat less than they want to.

“Overeating” is a significant public health concern, but little is known about how lay people conceptualize overeating. This study explored participants' conceptions of overeating. Participants were 175 university students and 296 community members (56% women) who were asked to rate the extent to which several statements reflected the concept of “overeating” (1 = Does not capture the meaning at all; 7 = Captures the meaning perfectly). Results showed that eating outside of hunger was viewed as being most strongly linked to the conceptualization of overeating; mindless eating, eating more than some normative amount, and a lack of restriction were all moderately linked to the conceptualization of overeating; and the quality of the food/eating style was rated as least relevant to the conceptualization of overeating. Participants with a higher BMI, participants who perceived themselves as fat, restrained eaters, and participants with an indication of eating pathology rated all of the constructs as more relevant to the concept of overeating than did their respective counterparts, but their overall pattern of responding was the same. The present research provides some initial insights into people's thoughts on what it means to “overeat,” which is important given that simply believing that one has overeaten (regardless of the actual amount consumed) can have adverse psychological and behavioral consequences. These insights provide an avenue for future research to explore whether lay conceptions could be more adaptively reshaped to reduce the negative effects of perceived overeating.

Modeling of food intake refers to the tendency for people to adjust the amount of food they eat to approximate the amount eaten by their eating companion. People eat more when eating with someone who eats a lot, and they eat less when eating with someone who eat very little. In this chapter, we summarize the research documenting the modeling effect. We also examine the potential impact of factors such as how hungry people are, their gender, and their body weight/size. Finally, we consider potential explanations for why people model the food intake of others, including the desire to affiliate with others and the social norms that are communicated by the other person’s behavior.

Research on modeling, consumption stereotypes, and impression management is consistent with our theory emphasizing norms of appropriateness. In this chapter we turn to some bodies of research that are less obviously related to norms of appropriateness; however, we believe they are related. The basic idea is that people can figure out what and how much it is appropriate to eat in a particular situation even when there are other people are not available to tell them or show them what is appropriate. Research on portion size shows that as the size of a portion increases so does the amount that people eat. We believe that portion size is an indirect social cue; presumably, “someone” has decided that a portion of a particular size is appropriate, so we use that cue to determine how much we should eat. People’s idea of appropriateness can also come from cultural knowledge about how eating is generally structured throughout a day, in terms of meals versus snacks. Meals and snacks tend to alternate, and meals tend to be large in relation to snacks. Thus, after eating a meal, it is appropriate to eat relatively lightly on the next eating occasion; after eating a snack, it is appropriateto eat relatively heavily on the next eating occasion. Research has shown that when people are induced to interpret a set of foods they are eating as a meal, they eat less on the next eating occasion than do those who are induced to interpret exactly the same set of foods as a snack. Similarly, beliefs about the caloric content of a food or foods can serve as an appropriateness cue. If we are eating something we believe to be highly caloric, our cultural knowledge tells us that it is appropriate to eat less of it than if we believe it to be relatively low in calories—and this can be independent of its actual caloric value. And finally, simply remembering or being reminded of what we have eaten in the recent past can affect subsequent eating—again, presumably because our cultural knowledge tells us what is appropriate on that later occasion.