Abstract
Increasing the relative availability of plant-based (versus animal source) foods seems promising in shifting consumption, but it remains unknown how and under what circumstances this happens. We performed two availability manipulations including different foods. The impact on food choice, social norm perceptions about what others do (descriptive) or approve of (injunctive), and salience was assessed. Non-vegetarian participants were visually (Study 1, n = 184) or physically (Study 2, n = 276) exposed to (a) four plant-based and two animal source foods or (b) vice versa. Participants chose one food item, either hypothetically (Study 1) or actually (Study 2), and reported the perceived social norms and salience of plant-based and animal source foods. The results showed no direct effects on food choice, injunctive norms, or salience. An increased proportion of plant-based (versus animal source) foods was interpreted in Study 1 as plant-based foods being less often chosen by others, whereas in Study 2, these foods were interpreted as being more often chosen (marginally significant), while animal source foods were interpreted as being less often chosen. The results suggest that a higher availability of plant-based foods influences descriptive norms, but future research should examine aspects potentially contributing to the contradictory normative interpretations (e.g., norm salience).
Generated Summary
This research investigates how the proportion of plant-based foods available influences food choice and social consumption norms among non-vegetarians. The study employs two experimental manipulations: visual exposure (Study 1) and physical exposure (Study 2) to varying proportions of plant-based and animal source foods in simulated supermarket settings. The study utilized a between-subjects design. The study was conducted using an online survey platform (Prolific Academic) in Study 1 and a lab-in-the-field setting in Study 2. The primary goal was to determine whether increased availability of plant-based foods would shift food choices and influence perceptions of salience, descriptive norms (what others do), and injunctive norms (what others approve of). The study also examined the role of meat attachment as a potential moderator. In Study 1, participants were visually exposed to different food options (four plant-based and two animal source foods, or vice versa), while in Study 2, participants were physically exposed to the options. Participants were then asked to select a food item and reported on their perceptions of social norms and salience related to plant-based and animal source foods.
Key Findings & Statistics
- In Study 1, 13.0% of participants chose a plant-based food option.
- In Study 1, no significant difference in hypothetical food choice was observed between conditions (p = 0.23).
- In Study 1, descriptive norms regarding plant-based foods showed a significant difference between conditions (p = 0.02).
- In Study 2, the percentage of participants choosing a plant-based food option was 54.0%.
- In Study 2, compared to the increased animal source foods condition, participants in the increased plant-based foods condition (OR = 1.30, p = 0.38) and the control condition (OR = 1.32, p = 0.36) did not show a significantly higher likelihood of choosing a plant-based food product.
- In Study 2, the interaction between condition and meat attachment on food choice was significant (interaction effect = 1.12, SE = 0.38, 95% CI (0.38, 1.87)).
- In Study 2, among participants with high meat attachment, increasing the availability of plant-based foods significantly increased the likelihood of selecting a plant-based food option (B = 1.76, SE = 0.54, 95% CI (0.70, 2.81), p < 0.01).
- In Study 2, the interaction between condition (control condition versus increased plant-based foods condition) and meat attachment on food choice was marginally significant (interaction effect = 0.55, SE = 0.33, 95% CI (-0.09, 1.19), p = 0.09).
Other Important Findings
- In Study 1, an increased availability of plant-based foods (versus animal source foods) was interpreted as plant-based foods being less often chosen by others.
- In Study 2, a trend was observed where participants perceived the increased availability of plant-based foods as being more often chosen by others, with a corresponding lower likelihood of choosing an animal source food.
- The study found that the effect of condition on hypothetical food selection may be mediated by perceived descriptive norms of the plant-based foods.
- In Study 2, physical exposure to increased availability of plant-based foods affected perceived descriptive norms of both plant-based and animal source foods.
Limitations Noted in the Document
- Both intervention studies differed in multiple aspects, making it difficult to attribute results to specific elements.
- Study 1 did not measure participants’ perceptions of autonomy, which could be relevant given the use of meat substitutes.
- The results of Study 2 may not be generalizable to males, as only females were included.
- The appearance of pasta sauces in Study 2 varied, which may have affected the results.
- A comparable availability intervention in an actual supermarket setting is recommended for future studies.
Conclusion
The study concludes that visual and physical exposure to a higher proportion of plant-based foods does not directly affect food choice, salience, or injunctive norms. However, the research highlights that participants with high meat attachment showed a greater likelihood of choosing plant-based options when physically exposed to them. The proportion of available foods also affected perceived descriptive norms, indicating that people adjust their understanding of what is typical in a setting based on the food environment. This suggests that the organization of food environments can shape social consumption norms. The study’s findings indicate that availability interventions are complex and may produce varied results depending on how the intervention is delivered and on consumer characteristics like meat attachment. The authors also suggest that availability cues may be interpreted in contradictory ways. In the online setting, individuals interpreted a higher availability of plant-based foods as a sign that they were less often chosen by others. In the lab study, the results indicated that participants viewed the foods as being more frequently chosen by others. Additionally, the study points out that the effectiveness of such interventions may be limited if they do not consider the context of existing consumer preferences. Future studies should investigate how to maximize the impact of these interventions by accounting for the complexity of consumer perceptions and the potential for reactance. The study also suggests that interventions may be most effective in promoting plant-based choices among those who already show a moderate openness to such foods, highlighting the importance of tailored approaches to promote sustainable consumption.