Do social norms play a role in explaining the impact on food selection of increasing the proportion of healthier food available?

INTERVENTION: The online and lab parts of the study will be conducted simultaneously. Online Study: Mixed design, with 3x2 between‐subjects conditions (3 availability conditions x 2 shelf fullness conditions), and one within‐subjects condition (manipulation level) Online Study: Participants are asked to estimate the percentage of sales – as a measure of perceived popularity – accounted for by healthier (over less‐healthy) products displayed in a series of photos. For each set of food and drink options, participants will be randomised to one of six groups to see displays that contain: Group 1: 75% healthier & 25% less‐healthy options, fuller shelves; Group 2: 50% healthier & 50% less‐healthy options, fuller shelves; Group 3: 25% healthier & 75% less‐healthy options, fuller shelves; Group 4: 75% healthier & 25% less‐healthy options, emptier shelves; Group 5: 50% healthier & 50% less‐healthy options, emptier shelves; Group 6: 25% healthier & 75% less‐healthy options, emptier shelves The primary endpoint is the perceived percentage of sales accounted for by healthier (over less‐healthy) options. Randomisation for the online study will be conducted via the inbuilt randomisation procedures on the Qualtrics platform. Lab Study: Between‐subjects design, with 4 groups (2 availability x 2 tray fullness conditions) Lab Study: Participants are offered a snack food at the end of a different study. They are randomly allocated to one of four conditions, which vary in terms of the mix of healthier and less healthy foods offered and the fullness of the tray on w CONDITION: Unhealthy diet ; Not Applicable PRIMARY OUTCOME: ; Online Study:; Perceived percentage of sales of healthier (over less‐healthy) products measured using the slider questions on the Qualtrics platform; ; Lab Study:; Food selection, measured by observing the selection of food (healthier or less healthy) from the tray during the study; SECONDARY OUTCOME: ; Online study:; Selection of products during the study; INCLUSION CRITERIA: 1. Adults aged over 18 years 2. Currently residing within the UK