Kirsten E. Bevelander

Social norms in food intake among normal weight and overweight children

This experimental study investigated whether childrens food intake is influenced by a peers intake directly and over time and whether this depends upon weight status. The study consisted of two sessions taking place at Dutch primary schools. During the first (social modeling) session, the participants (N=223) were asked to solve a puzzle with a same-sex normal weight confederate who was instructed to either eat nothing, a small or large amount. In the second session (about two days later), the participants had to solve the puzzle alone while they could freely eat. The study involved a three (no, low, high confederate intake) by two (normal weight, overweight) between-participants design. An interaction effect in the first session suggested that overweight children might be triggered to (over)eat when a peer eats a high amount of snack food, whereas the food intake of normal weight children seemed to depend on whether the confederate did actually eat, regardless of the amount. The guideline set during the first session persisted over time and influenced food intake during the second session, while differences between normal- and overweight children became insignificant. Peers can set an example as to what food intake is appropriate which could affect long-term food intake.

The Role of Explicit and Implicit Self-Esteem in Peer Modeling of Palatable Food Intake: A Study on Social Media Interaction among Youngsters

Objective This experimental study investigated the impact of peers on palatable food intake of youngsters within a social media setting. To determine whether this effect was moderated by self-esteem, the present study examined the roles of global explicit self-esteem (ESE), body esteem (BE) and implicit self-esteem (ISE). Methods Participants (N = 118; 38.1% boys; M age 11.14±.79) were asked to play a computer game while they believed to interact online with a same-sex normal-weight remote confederate (i.e., instructed peer) who ate either nothing, a small or large amount of candy. Results Participants modeled the candy intake of peers via a social media interaction, but this was qualified by their self-esteem. Participants with higher ISE adjusted their candy intake to that of a peer more closely than those with lower ISE when the confederate ate nothing compared to when eating a modest (β = .26, p = .05) or considerable amount of candy (kcal) (β = .32, p = .001). In contrast, participants with lower BE modeled peer intake more than those with higher BE when eating nothing compared to a considerable amount of candy (kcal) (β = .21, p = .02); ESE did not moderate social modeling behavior. In addition, participants with higher discrepant or “damaged” self-esteem (i.e., high ISE and low ESE) modeled peer intake more when the peer ate nothing or a modest amount compared to a substantial amount of candy (kcal) (β = −.24, p = .004; β = −.26, p<.0001, respectively). Conclusion Youngsters conform to the amount of palatable food eaten by peers through social media interaction. Those with lower body esteem or damaged self-esteem may be more at risk to peer influences on food intake.

The effect of a fictitious peer on young children's choice of familiar v. unfamiliar low- and high-energy-dense foods

The present experimental study was the first to investigate the impact of a remote (non-existent) peer on childrens food choice of familiar v. unfamiliar low- and high-energy-dense food products. In a computer task, children (n 316; 50·3 % boys; mean age 7·13 (SD 0·75) years) were asked to choose between pictures of familiar and unfamiliar foods in four different choice blocks using the following pairs: (1) familiar v. unfamiliar low-energy-dense foods (fruits and vegetables), (2) familiar v. unfamiliar high-energy-dense foods (high sugar, salt and/or fat content), (3) familiar low-energy-dense v. unfamiliar high-energy-dense foods and (4) unfamiliar low-energy-dense v. familiar high-energy-dense foods. Participants who were not in the control group were exposed to the food choices (either always the familiar or always the unfamiliar food product) of a same-sex and same-age fictitious peer who was supposedly completing the same task at another school. The present study provided insights into childrens choices between (un)familiar low- and high-energy-dense foods in an everyday situation. The findings revealed that the use of fictitious peers increased childrens willingness to try unfamiliar foods, although children tended to choose high-energy-dense foods over low-energy-dense foods. Intervention programmes that use peer influence to focus on improving childrens choice of healthy foods should take into account childrens strong aversion to unfamiliar low-energy-dense foods as well as their general preference for familiar and unfamiliar high-energy-dense foods.

The effect of an intervention on schoolchildren's susceptibility to a peer's candy intake

Background/objectives:The aim of the study was to pilot test two interventions designed to reduce children’s susceptibility to peers’ candy intake and to determine if interventions had different effects on boys and girls.Subjects/methods:In the standard intervention, peer modeling was explained while communicating the importance of not following other’s food intake by means of photos, video clips and interactive tasks. A second animated intervention was similar but added a monkey puppet as a (cue) reminder. A social modeling component was conducted 1 day after the intervention to test whether the interventions affected the extent to which children model their peers’ eating. During the modeling session, the participants’ (N=141; 78% boys, mean age=7.84±0.72 years) solved a puzzle with a same-sex ‘confederate’ who was instructed to eat chocolate candy when he/she was covertly signaled. The monkey puppet was put in sight to test whether the monkey served as a cue reminder in the animated intervention. Candy intake was compared across control and intervention conditions.Results:The standard intervention reduced candy intake in boys but not girls. Nevertheless, children still remained susceptible to a peer’s eating. There was no significant effect of the animated intervention on consumption.Conclusions:There are gender differences when children are exposed to an (over)eating peer. Although interventions are effective, social norms can be powerful. Social networks should be leveraged when possible. The study is registered at the Dutch Trial Register: NTR3459.

Imitation of snack food intake among normal-weight and overweight children

This study investigated whether social modeling of palatable food intake might partially be explained by the direct imitation of a peer reaching for snack food and further, assessed the role of the childrens own weight status on their likelihood of imitation during the social interaction. Real-time observations during a 10-min play situation in which 68 participants (27.9% overweight) interacted with normal-weight confederates (instructed peers) were conducted. Childrens imitated and non-imitated responses to the confederates food picking movements were compared using a paired sample t-test. In addition, the pattern of likelihood of imitation was tested using multilevel proportional hazard models in a survival analysis framework. Children were more likely to eat after observing a peer reaching for snack food than without such a cue [t(67) = 5.69, P < 0.0001]. Moreover, findings suggest that children may display different imitation responses during a social interaction based on their weight status (HR = 2.6, P = 0.03, 95% CI = 1.09–6.20). Overweight children were almost twice as likely to imitate, whereas normal-weight children had a smaller chance to imitate at the end of the interaction. Further, the mean difference in the likelihood of imitation suggest that overweight children might be less likely to imitate in the beginning of the interaction than normal-weight children. The findings provide preliminary evidence that childrens imitation food picking movements may partly contribute to social modeling effects on palatable food intake. That is, a peer reaching for food is likely to trigger childrens snack intake. However, the influence of others on food intake is a complex process that might be explained by different theoretical perspectives.

Methodological and reporting quality in laboratory studies of human eating behavior

The methodological quality and reporting practices of laboratory studies of human eating behavior determine the validity and replicability of nutrition science. The aim of this research was to examine basic methodology and reporting practices in recent representative laboratory studies of human eating behavior. We examined laboratory studies of human eating behavior (N = 140 studies) published during 2016. Basic methodology (e.g., sample size, use of participant blinding) and reporting practices (e.g., information on participant characteristics) were assessed for each study. Some information relating to participant characteristics (e.g., age, gender) and study methodology (e.g., length of washout periods in within-subjects studies) were reported in the majority of studies. However, other aspects of study reporting, including participant eligibility criteria and how sample size was determined were frequently not reported. Studies often did not appear to standardize pre-test meal appetite or attempt to blind participants to study aims. The average sample size of studies was small (between-subjects design studies in particular) and the primary statistical analyses in a number of studies (24%) were reliant on very small sample sizes that would be likely to produce unreliable results. There are basic methodology and reporting practices in the laboratory study of human eating behavior that are sub-optimal and this is likely to be affecting the validity and replicability of research. Recommendations to address these issues are discussed.

Television watching and the emotional impact on social modeling of food intake among children

The main goal of this study was to test whether exposure to happy, neutral, or sad media content influences social modeling effects of (snack) food intake in young children. The study was conducted at 14 Dutch urban and suburban primary schools. The participants (N=112) were asked to watch a movie with a same-sex normal-weight confederate who was instructed to eat either nothing or a standardized amount of snack food (10 chocolate-coated peanuts). The study involved a 3 (movie clips: happy, neutral, and sad)×2 (peers food intake: no intake versus a standardized intake) between-participants design. A significant interaction between the movie clip condition and intake condition was found (F(2,102)=3.30, P=.04, Cohens f(2)=.20). Positive as well as negative emotions were found to lead to adjustment to the intake of a peer, as compared to that of children in the neutral movie condition. The findings suggest that children eat more mindlessly when watching an emotional movie and, therefore, respond more automatically to a peers food intake, whereas children may be less susceptible to a peers intake while watching a neutral movie. As young children are not in the position to choose their food consumption environment yet, parents and schools should provide consumption settings that limit eating in front of the television.

An integrated model of fruit, vegetable, and water intake in young adolescents.

Objective: In this study, we tested an integrated model for why young adolescents consume fruit, vegetables, and water. The model was based on evidence from studies applying three dominant theoretical approaches, including planned behavior, social norms, and intrinsic motivation. Method: The integrated model was tested with structural equation modeling using four data-collection waves of the MyMovez Project (MyMovez, 2017) in which 953 young adolescents (53.9% girls; Mage = 11.19, SDage = 1.36) participated. Self-reported measures were used to assess young adolescents’ fruit, vegetable, and water consumption, self-efficacy, attitude, social norms of parents and peers, behavioral intentions, and intrinsic motivation. Results: The analyses revealed that young adolescents’ intrinsic motivation to eat fruits and vegetables or drink water predicted changes in their fruit, vegetable, and water consumption. Furthermore, adolescents’ perceived descriptive norm of parents (i.e., perception of the prevalence of their parents’ water consumption) also predicted changes, but only for water consumption. Conclusion: The current findings show that young adolescents’ intrinsic motivation (and, to some extent, parental social norms) is the strongest predictor of their consumption of fruit, vegetables, and water. It is important to note, behavioral intentions do not predict their actual behavior over time. Consequently, interventions should focus on increasing young adolescents’ intrinsic motivation to perform the targeted behavior while incorporating the influence of the social context.

Eating for two? Protocol of an exploratory survey and experimental study on social norms and norm-based messages influencing European pregnant and non-pregnant women's eating behavior

The social context is an important factor underlying unhealthy eating behavior and the development of inappropriate weight gain. Evidence is accumulating that powerful social influences can also be used as a tool to impact people’s eating behavior in a positive manner. Social norm-based messages have potential to steer people in making healthier food choices. The research field on nutritional social norms is still emerging and more research is needed to gain insights into why some people adhere to social norms whereas others do not. There are indications stemming from empirical studies on social eating behavior that this may be due to ingratiation purposes and uncertainty reduction. That is, people match their eating behavior to that of the norm set by their eating companion(s) in order to blend in and be part of the group. In this project, we explore nutritional social norms among pregnant women. This population is particularly interesting because they are often subject to unsolicited advice and experience social pressure from their environment. In addition, their pregnancy affects their body composition, eating pattern, and psychosocial status. Pregnancy provides an important window of opportunity to impact health of pregnant women and their child. Nevertheless, the field of nutritional social norms among pregnant women is understudied and more knowledge is needed on whether pregnant women use guidelines from their social environment for their own eating behavior. In this project we aim to fill this research gap by means of an exploratory survey (Study 1) assessing information about social expectations, (mis)perceived social norms and the role of different reference groups such as other pregnant women, family, and friends. In addition, we conduct an online experiment (Study 2) testing to what extent pregnant women are susceptible to social norm-based messages compared to non-pregnant women. Moreover, possible moderators are explored which might impact women’s susceptibility to social norms as well as cultural aspects that co-determine which social norms and guidelines exist. The project’s findings could help design effective intervention messages in promoting healthy eating behavior specifically targeted to European pregnant women.

Youth's social network structures and peer influences: Study protocol MyMovez project - Phase I

BackgroundYouth are an important target group for social network interventions, because they are particularly susceptible to the adaptation of healthy and unhealthy habits and behaviors of others. They are surrounded by ‘social influence agents’ (i.e., role models such as family, friends and peers) that co-determine their dietary intake and physical activity. However, there is a lack of systematic and comprehensive research on the implementation of a social network approach in health campaigns. The MyMovez research project aims to fill this gap by developing a method for effective social network campaign implementation. This protocol paper describes the design and methods of Phase I of the MyMovez project, aiming to unravel youth’s social network structures in combination with individual, psychosocial, and environmental factors related to energy intake and expenditure. In addition, the Wearable Lab is developed to enable an attractive and state-of-the-art way of collecting data and online campaign implementation via social networks.MethodsPhase I of the MyMovez project consists of a large-scale cross-sequential cohort study (N = 953; 8-12 and 12-15 y/o). In five waves during a 3-year period (2016-2018), data are collected about youth’s social network exposure, media consumption, socialization experiences, psychological determinants of behavior, physical environment, dietary intake (snacking and drinking behavior) and physical activity using the Wearable Lab. The Wearable Lab exists of a smartphone-based research application (app) connected to an activity tracking bracelet, that is developed throughout the duration of the project. It generates peer- and self-reported (e.g., sociometric data and surveys) and experience sampling data, social network beacon data, real-time physical activity data (i.e., steps and cycling), location information, photos and chat conversation data from the app’s social media platform Social Buzz.DiscussionThe MyMovez project - Phase I is an innovative cross-sequential research project that investigates how social influences co-determine youth’s energy intake and expenditure. This project utilizes advanced research technologies (Wearable Lab) that provide unique opportunities to better understand the underlying processes that impact youths’ health-related behaviors. The project is theoretically and methodologically pioneering and produces a unique and useful method for successfully implementing and improving health campaigns.