Changing the availability and positioning of more vs. less environmentally sustainable products: A randomised controlled trial in an online experimental supermarket.

Food purchasing behaviours are shaped by the choices available to shoppers and the way they are offered for sale. This study tested whether prominent positioning of more sustainable food items online and increasing their relative availability might reduce the environmental impact of foods selected in a 2x2 (availability x position) factorial randomised controlled trial. Participants (n = 1179) selected items in a shopping task in an experimental online supermarket. The availability intervention added lower-impact products to the regular range. The positioning intervention biased product order to give prominence to lower-impact products. The primary outcome was the environmental impact score (ranging from 1 "least impact" to 5 "most impact", of each item in shopping baskets) analysed using Welch's ANOVA. Secondary outcomes included interactions (analysed via linear regression) by gender, age group, education, income and meat consumption and we assessed intervention acceptability (using different frames) in a post-experiment questionnaire. Compared to control (mean = 21.6), mean eco quintile score was significantly reduced when availability & order was altered (-2.30; 95%CI: 3.04; -1.56) and when order only was changed (-1.67; 95%CI: 2.42; -0.92). No significant difference between availability only (-0.02; 95%CI: 0.73; 0.69) and control was found. There were no significant interactions between interventions or by demographic characteristics. Both interventions were acceptable under certain frames (positioning emphasising lower-impact products: 70.3% support; increasing lower-impact items: 74.3% support). Prominent positioning of more sustainable products may be an effective strategy to encourage more sustainable food purchasing. Increasing availability of more sustainable products alone did not significantly alter the environment impact of products selected.

Testing the impact of overt and covert ordering interventions on sustainable consumption choices: A randomised controlled trial.

Food products have significant impacts on the environment over their life cycle. We investigated whether displaying products in ascending order of carbon footprint in an online supermarket environment can shift consumer choices towards more sustainable options. We examined whether the effect of the ordering intervention differs when the ordering is overt (information about the ordering is explicit), compared to when it is covert (participants not told about the ordering). We conducted a three-arm parallel-group randomised trial using 1842 online participants from England, Wales, and Northern Ireland. Participants shopped for a meal, choosing one product from each of six product categories in a simulated online supermarket. Six products were listed vertically on each product-category page. Products were randomly ordered for the control arm but ordered by carbon footprint in the covert and overt ordering arms. In the overt ordering arm, a statement was displayed at the top of each product page about the ordering of products. The primary outcome was whether one of the three most sustainable products was chosen in each product category. There was no effect of the covert ordering on the probability of choosing more sustainable products compared with the control arm (OR = 0.97, 95% CI 0.88-1.07, p = 0.533). Furthermore, we did not find evidence that the effects of the covert ordering and overt ordering differed (p = 0.594). Within the control condition, products in different positions were chosen with similar frequencies, suggesting that product positioning does not have an impact on choices. This may explain why re-ordering products had no effect. In the overt condition, only 19.5% of people correctly answered that the products were ordered according to sustainability in a follow-up question, suggesting that they didn't notice the statement. Results suggest that choices for grocery products might be too ingrained to be changed by subtle rearrangements of choice architecture like the ordering interventions, and highlight the difficulty of conveying information effectively to consumers in the online grocery shopping environment.

The nature and persistence of the effects of posthypnotic suggestions on food preferences: The final report of an online study.

The persistence of food preferences, which are crucial for diet-related decisions, is a significant obstacle to changing unhealthy eating behavior. To overcome this obstacle, the current study investigates whether posthypnotic suggestions (PHSs) can enhance food-related decisions by measuring food choices and subjective ratings. After assessing hypnotic susceptibility in Session 1, at the beginning of Session 2, a PHS was delivered aiming to increase the desirability of healthy food items (e.g., vegetables and fruit). After the termination of hypnosis, a set of two tasks was administrated twice, once when the PHS was activated and once deactivated in counterbalanced order. The task set consisted of rating 170 pictures of food items, followed by an online supermarket where participants were instructed to select enough food from the same item pool for a fictitious week of quarantine. After 1 week, Session 3 mimicked Session 2 without renewed hypnosis induction to assess the persistence of the PHS effects. The Bayesian hierarchical modeling results indicate that the PHS increased preferences and choices of healthy food items without altering the influence of preferences in choices. In contrast, for unhealthy food items, not only both preferences and choices were decreased due to the PHS, but also their relationship was modified. That is, although choices became negatively biased against unhealthy items, preferences played a more dominant role in unhealthy choices when the PHS was activated. Importantly, all effects persisted over 1 week, qualitatively and quantitatively. Our results indicate that although the PHS affected healthy choices through resolve, i.e., preferred more and chosen more, unhealthy items were probably chosen less impulsively through effortful suppression. Together, besides the translational importance of the current results for helping the obesity epidemic in modern societies, our results contribute theoretically to the understanding of hypnosis and food choices.

The Nature and Persistence of Posthypnotic Suggestions' Effects on Food Preferences: An Online Study.

Food preferences are crucial for diet-related decisions, which substantially impact individual health and global climate. However, the persistence of unfavorable food preferences is a significant obstacle to changing eating behavior. Here we explored the effects of posthypnotic suggestions (PHS) on food-related decisions by measuring food choices, subjective ratings, and indifference points. In Session 1, demographic data and hypnotic susceptibility of participants were assessed. In Session 2, following hypnosis induction, PHS aiming to increase the desirability of healthy food was delivered. Afterward, a task set was administrated twice, once when PHS was activated and once deactivated. The order of PHS activation was counterbalanced across participants. The task set included a liking-rating task for 170 pictures of different food items, followed by an online supermarket where participants were instructed to select enough food for a fictitious week of quarantining from the same item pool. After 1 week, Session 3 repeated Session 2 without hypnosis induction in order to assess the persistence of PHS. The crucial dependent measures were food choices, subjective ratings, and the indifference points as a function of time and PHS condition.

High BMI Predicts Attention to Less Healthy Product Sets: Can a Prompt Lead to Consideration of Healthier Sets of Products?

While the food environment has been implicated in diet-related health disparities, individuals' ability to shape the food environment by limiting attention to a subset of products has not been studied. We examine the relationship between BMI category and consideration set-the products the individual considers before making a final choice-in an online hypothetical shopping experiment. Specifically, we focus on the healthiness of the consideration set the individual selected. Secondly, we examined the interaction of a health prompt (versus a no-prompt control) with BMI category on the healthiness of the consideration set. We used linear probability models to document the relationship between weight status and consideration set, between prompt and consideration set, and the effect of the interaction between prompt and weight status on consideration set. We found that (1) obese individuals are 10% less likely to shop from a consideration set that includes the healthy options, (2) viewing the prompt increased the probability of choosing a healthy consideration set by 9%, and (3) exposure to the prompt affected individuals in different BMI categories equally. While obese individuals are more likely to ignore healthier product options, a health-focused prompt increases consideration of healthy options across all BMI categories.