Dataset Information

The Role of Social Norms in the Portion Size Effect: Reducing Normative Relevance Reduces the Effect of Portion Size on Consumption Decisions.

ABSTRACT: People typically eat more from large portions of food than from small portions. An explanation that has often been given for this so-called portion size effect is that the portion size acts as a social norm and as such communicates how much is appropriate to eat. In this paper, we tested this explanation by examining whether manipulating the relevance of the portion size as a social norm changes the portion size effect, as assessed by prospective consumption decisions. We conducted one pilot experiment and one full experiment in which participants respectively indicated how much they would eat or serve themselves from a given amount of different foods. In the pilot (N = 63), we manipulated normative relevance by allegedly basing the portion size on the behavior of either students of the own university (in-group) or of another university (out-group). In the main experiment (N = 321), we told participants that either a minority or majority of people similar to them approved of the portion size. Results show that in both experiments, participants expected to serve themselves and to eat more from larger than from smaller portions. As expected, however, the portion size effect was less pronounced when the reference portions were allegedly based on the behavior of an out-group (pilot) or approved only by a minority (main experiment). These findings suggest that the portion size indeed provides normative information, because participants were less influenced by it if it communicated the behaviors or values of a less relevant social group. In addition, in the main experiment, the relation between portion size and the expected amount served was partially mediated by the amount that was considered appropriate, suggesting that concerns about eating an appropriate amount indeed play a role in the portion size effect. However, since the portion size effect was weakened but not eliminated by the normative relevance manipulations and since mediation was only partial, other mechanisms may also play a role.

SUBMITTER: Versluis I

PROVIDER: S-EPMC4885850 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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The Role of Social Norms in the Portion Size Effect: Reducing Normative Relevance Reduces the Effect of Portion Size on Consumption Decisions.

Versluis Iris I Papies Esther K EK

Frontiers in psychology 20160531

People typically eat more from large portions of food than from small portions. An explanation that has often been given for this so-called portion size effect is that the portion size acts as a social norm and as such communicates how much is appropriate to eat. In this paper, we tested this explanation by examining whether manipulating the relevance of the portion size as a social norm changes the portion size effect, as assessed by prospective consumption decisions. We conducted one pilot exp ...[more]

PMID: 27303324

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Project description:AimsTo test whether reducing the standard serving size of alcoholic beverages would reduce voluntary alcohol consumption in a laboratory (study 1) and a real-world drinking environment (study 2). Additionally, we modelled the potential public health benefit of reducing the standard serving size of on-trade alcoholic beverages in the United Kingdom.DesignStudies 1 and 2 were cluster-randomized experiments. In the additional study, we used the Sheffield Alcohol Policy Model to estimate the number of deaths and hospital admissions that would be averted per year in the United Kingdom if a policy that reduces alcohol serving sizes in the on-trade was introduced.SettingA semi-naturalistic laboratory (study 1), a bar in Liverpool, UK (study 2).ParticipantsStudents and university staff members (study 1: n = 114, mean age = 24.8 years, 74.6% female), residents from local community (study 2: n = 164, mean age = 34.9 years, 57.3% female).Interventions and comparatorsIn study 1, participants were assigned randomly to receive standard or reduced serving sizes (by 25%) of alcohol during a laboratory drinking session. In study 2, customers at a bar were served alcohol in either standard or reduced serving sizes (by 28.6-33.3%).MeasurementsOutcome measures were units of alcohol consumed within 1 hour (study 1) and up to 3 hours (study 2). Serving size condition was the primary predictor.FindingsIn study 1, a 25% reduction in alcohol serving size led to a 20.7-22.3% reduction in alcohol consumption. In study 2, a 28.6-33.3% reduction in alcohol serving size led to a 32.4-39.6% reduction in alcohol consumption. Modelling results indicated that decreasing the serving size of on-trade alcoholic beverages by 25% could reduce the number of alcohol-related hospital admissions and deaths per year in the United Kingdom by 4.4-10.5% and 5.6-13.2%, respectively.ConclusionsReducing the serving size of alcoholic beverages in the United Kingdom appears to lead to a reduction in alcohol consumption within a single drinking occasion.

Dataset Information

The Role of Social Norms in the Portion Size Effect: Reducing Normative Relevance Reduces the Effect of Portion Size on Consumption Decisions.

Publications

The Role of Social Norms in the Portion Size Effect: Reducing Normative Relevance Reduces the Effect of Portion Size on Consumption Decisions.

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