Impact of altering the available food options on selection: Potential mediation by social norms

Abstract

Increasing the availability of lower-energy foods increases their selection. The current studies examine the extent to which this effect could be mediated by social norms – assessed by perceived popularity of foods – which may be implied by their relative availability. Study 1 (Online): 2340 UK adults estimated the perceived popularity of products. Participants were randomised to see photos of cafeteria shelves varying in the availability of lower-energy options ( 1 / 4 lower-energy; 1 / 2 lower-energy; 3 / 4 lower-energy) and fullness of shelves (fuller; emptier). Study 2 (Laboratory): 139 English adults were asked to select a snack. Participants were randomised to select from trays varying in the availability of the lower-energy option ( 1 / 3 lower-energy; 2 / 3 lower-energy) and fullness of tray (fuller; emptier). In Study 1, evidence for an interaction was found, such that when shelves were fuller, a higher proportion of lower-energy options led to greater perceived popularity of lower-energy products ( 1 / 4 lower-energy: 40.9% (95%CIs: 40.1,41.8); 3 / 4 lower-energy: 47.2% (46.3,48.0)), whereas when shelves were emptier, a higher proportion of lower-energy options led to lower perceived popularity ( 1 / 4 lower-energy: 48.4% (47.5,49.2); 3 / 4 lower-energy: 39.2% (38.3,40.0)). In Study 2, when the tray was fuller, participants were more likely – albeit non-significantly – to select a lower-energy snack when 2 / 3 of the available snacks were lower-energy (35.7% (18.5,52.9)) than when 1 / 3 were lower-energy (15.4% (4.2,26.5)). For emptier trays, lower-energy selections decreased as the relative availability of lower-energy snacks increased ( 1 / 3 lower-energy snacks: 36.0% (17.9,54.1); 2 / 3 lower-energy snacks: 27.8% (13.9,41.7)). These studies provide novel evidence that social norms may mediate the impact of availability on food selection. In addition, they suggest that the effect of availability may be moderated by display layout through its impact on perceived product popularity.

Changing the assortment of available food and drink for leaner, greener diets

“…This pattern is replicated in a systematic review of the effect of diet based interventions on people with intellectual disabilities 38. In addition, a mega-analysis that pooled data from four studies conducted online394041 and two laboratory studies with experimental designs4240 (21 360 observations from 7375 participants) assessing the effect of availability interventions on healthier food selection in general populations indicated minimal differences in effect by socioeconomic position 43…”

Impact on alcohol selection and online purchasing of changing the proportion of available non-alcoholic versus alcoholic drinks: A randomised controlled trial

“…Further studies are needed to disentangle this and investigate potential mechanisms more broadly; noting that there is some preliminary exploration of possible mechanisms in food contexts. 6,25,26 Importantly, the overall number of drinks that participants selected and purchased remained similar between groups, suggesting that effects were a result of shifting, rather than necessarily restricting, choices. This implies overall drink sales and potentially revenues may be relatively unchanged if such an intervention were to be implemented, albeit dependent on non-alcoholic drink pricing.…”

Explaining the effect on food selection of altering availability: two experimental studies on the role of relative preferences

“…One of these potential pathways suggests that the effects of availability could be explained in terms of individuals tending to choose their most-preferred option in each instance – based on a mixture of their taste preferences from prior exposures [ 6 ] alongside their current needs and context [ 7 , 8 ]. Other mechanisms, such as social norms regarding selection of different foods, may also act in parallel [ 9 ].…”