Virtual delivery app
HAND PRESENTATION, SHOP
A virtual delivery app (Supplementary material II) was created using the program Inquisit 6, and modelled on a popular UK-based food delivery platform. Three large chain food outlets in the UK (a coffee shop, a sandwich shop, and a fast food outlet) were simulated as they each typically offer products at a larger size with value pricing, and cover a range of food types ordered through delivery apps (i.e., beverages, sandwiches, meals). After completing baseline questionnaires, participants were informed they would be completing hypothetical food and drink orders, and asked to imagine they were going to pay for and receive the items ordered. On the following page, participants were asked to imagine they were ordering a drink from a coffee shop chain at whichever time of day they would usually purchase a drink from a café. There were 21 possible beverages for participants to order. Once participants had chosen their drink, they were asked to select a size (medium or large, except for n = 4 beverages where only a medium was available). Finally, participants specified addition of milk, sugar or sweetener, and other preferences.For the sandwich outlet order, participants were asked to imagine they were ordering a sandwich for lunch. There were 21 possible filling options. Once a choice was made, participants were required to select a size (6-inch or 12-inch) and then make various specifications (bread type, additional fillings, sauce). Participants were then asked if they wanted to see the sides menu. If they selected yes, they were shown the 15 available sides which they could add to their order or continue, before being asked if they wanted to see the drinks menu. If they selected yes, participants were shown the 15 available drinks which they could add to their order or complete their order.For the fast food outlet, participants were asked to imagine they were ordering an evening meal. There were 21 possible main meal component options (e.g. burgers, wraps, chicken dishes). Once participants made their choice, they were asked to specify a meal size (medium or large; for an example screen shot see Fig. Prices, calorie content and presentation of menu items were obtained in 2022 from a major UK food delivery platform. In calorie labelling conditions, each food option had calorie information in the description, and a statement of calorie guidelines visible on the page (“Adults need around 2000kcals a day”). For proportional pricing conditions, prices were calculated for any items with multiple size options. Prices for larger sizes were determined by calculating the percentage increase in kilocalories (herein: kcals) between the smaller and larger size options and translating that into the same percentage increase in price (see supplementary material III for an example).
Example of virtual delivery app