Nudging with Attribution Bias: Promoting Healthy Over Unhealthy Drink Preferences

The intervention aims to exogenously manipulate subjects' hunger level prior to consumption of a target snack, with the aim to vary consumption experience across treatments. Participants will be asked to fast for five hours prior to the experiment. They will then be randomly assigned to either the treatment or control group using computer-based randomization software. The treatment group will remain hungry, while the control group will receive a neutral snack (e.g., Ritz biscuits) to offset their hunger. Following hunger manipulation, both groups will be provided with a healthy food snack (e.g., Baked chips) to consume, after which they will rate their consumption experience. The treatment group is expected to report higher ratings since they consume the snack under an arousal state (hunger), resulting in a better consumption experience than subjects in the control, who are satiated before consuming the healthy snack.

2026-04-01

2026-07-01

1. Subjects' choices between the healthy and equivalent, unhealthy snack in the choice task will be compared between control and treatment.
2. Event-Related Potentials (ERPs) will be measured during the cue exposure task and key components (e.g., P1, N1, N2, P3, LPP, RewP) will be compared between control and treatment.

Age, gender, ethnicity, income, education, exercise frequency and intensity, duration since last meal, current appetite, number of meals and snacks per day, expected time until next meal, consumption experience.

The experiment is conducted across two days. On the first day, subjects will consume a healthy snack under a control or treatment condition. On day two, they will make choices between the healthy snack and an equivalent, unhealthy alternative in a choice task. Neurophysiological indicators of preferences for the healthy and unhealthy snacks will also be collected during a cue exposure task.

The experiment is conducted across two days. The first day involves the treatment manipulation, where consumption experience with a healthy snack will be exogenously varied between a control and treatment group. The manipulation will be hunger based, where all subjects will be asked to fast for 5 hours prior to arriving at their first-day session. Subjects in the control group will be provided with a neutral snack (e.g., Ritz biscuits) before starting to offset their hunger, while those in the treatment group will not. Subjects will then report their hunger levels, which will be used to confirm successful hunger manipulation, after which they will be asked to consume the healthy food snack. During consumption of the healthy product, all subjects will first consume one half, after which they will answer a very short intermediate questionnaire before consuming the second half. The intermediate questionnaire will consist of two questions about how tasty the product is and how excited they are to consume the second half. After consuming both halves of the healthy product, subjects will answer a short questionnaire to collect sociodemographic data, as well as behavioral information related to their food consumption, including how many meals they typically have per day, how many times they typically snack per day, and how often they consume fried and baked chips. The first day’s session will then conclude with measuring subjects’ weight and height to calculate BMI.

The second day’s session will start with a short questionnaire asking subjects to report how much they enjoyed consuming the healthy snack in day 1 and if they would consume the snack again if it were available to them. They will also report if they had consumed the healthy snack/unhealthy equivalent (e.g., baked and fried chips) between days 1 and 2. Subjects will then complete two tasks in a randomized order to elicit behavioral and psychophysiological indicators of their preferences for the healthy food snack consumed in day 1 compared to an equivalent unhealthy alternative. The first is a choice task where subjects will be presented with an image of the healthy and unhealthy snacks and asked to make a choice between them in an incentive compatible environment (i.e., real choices). The second is a cue exposure task, where subjects will be presented with a random sequence of 90 images, consisting of 30 non-food images (e.g., office items), 30 images of the healthy snack they consumed in day 1, and 30 images of the equivalent unhealthy alternative snack. The images will be presented in a quasi-random order that avoids more than 4 repetitions from the same category.

Participants will be assigned equally to Control and Treatment groups (60 in each). First, each of the 120 participants is labeled with a unique identifier. A random number is then generated for each ID from a uniform distribution. The numbers are ranked from lowest to highest, and the 60 IDs associated with the lowest numbers are placed in the Control group, while the remaining 60 are placed in the Treatment group. This ensures an exact 50–50 split while preserving random assignment.

Individual

No

Not clustered

120

60

Choice outcome minimum detectable effect size: 0.230 (m1=0.568, sd1=0.502, sd2=0.381)