Visual exposure to large and small portion sizes and perceptions of portion size normality: Three experimental studies

Imogen Cuckson,Jeffrey M Brunstrom,Melissa Oldham,Peter J Rogers,Charlotte A Hardman,Eric Robinson

doi:10.1016/j.appet.2015.12.010

Imogen Cuckson, Jeffrey M Brunstrom + Show 4 more

Open Access

https://doi.org/10.1016/j.appet.2015.12.010

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Journal: Appetite	Publication Date: Dec 17, 2015
Citations: 52	License type: cc-by

Affiliation: University of Liverpool, University of Bristol

Abstract

Portion sizes of many foods have increased in recent times. In three studies we examined the effect that repeated visual exposure to larger versus smaller food portion sizes has on perceptions of what constitutes a normal-sized food portion and measures of portion size selection. In studies 1 and 2 participants were visually exposed to images of large or small portions of spaghetti bolognese, before making evaluations about an image of an intermediate sized portion of the same food. In study 3 participants were exposed to images of large or small portions of a snack food before selecting a portion size of snack food to consume. Across the three studies, visual exposure to larger as opposed to smaller portion sizes resulted in participants considering a normal portion of food to be larger than a reference intermediate sized portion. In studies 1 and 2 visual exposure to larger portion sizes also increased the size of self-reported ideal meal size. In study 3 visual exposure to larger portion sizes of a snack food did not affect how much of that food participants subsequently served themselves and ate. Visual exposure to larger portion sizes may adjust visual perceptions of what constitutes a ‘normal’ sized portion. However, we did not find evidence that visual exposure to larger portions altered snack food intake.

Highlights

Food portion sizes have increased for a number of food types in recent years (Nielsen & Popkin, 2003; Smiciklas-Wright, Mitchell, Mickle, Goldman, & Cook, 2003)
No participants directly guessed the aims of the study, four participants reported that they believed the study may have been related to portion size normality
Participants exposed to the large portions of spaghetti bolognese believed a normal serving of spaghetti bolognese would be larger than did participants exposed to small portions of spaghetti bolognese [t (97) 1⁄4 5.2, p < .001, d 1⁄4 1.05] and participants in the control condition [t (96) 1⁄4 2.0, p 1⁄4 .046, d 1⁄4 0.41]

Summary

Introduction

Food portion sizes have increased for a number of food types in recent years (Nielsen & Popkin, 2003; Smiciklas-Wright, Mitchell, Mickle, Goldman, & Cook, 2003). Recent work by Marchiori et al suggests that portion size may act as a cue or ‘norm’ which influences meal size (Marchiori, Papies, & Klein, 2014), such that when making evaluations about portion size, individuals anchor their decisions relative to the size of the portion size being evaluated In support of this ‘norm’ based or ‘anchoring’ account, studies have shown that portion sizes can differ significantly in size whilst still being rated as ‘normal’ or appropriate (Diliberti, Bordi, Conklin, Roe, & Rolls, 2004; Robinson, te Raa, & Hardman, 2015). Based on the visual adaptation literature, one possible consequence of increases in food portion sizes is that more frequent visual exposure to larger portion sizes recalibrates visual perceptions of what a ‘normal’

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