As online grocery shopping grows, digital nudges have received increasing attention. Although previous studies have reported positive effects of swap recommendations in encouraging healthier food choices, their findings were based on solely hypothetical choices. The present study addresses this limitation by having participants fulfill a shopping task for which they would receive some of their purchased products and pay realistic prices. Additionally, this study included only plant-based products and did not use messages to promote their health benefits. We created a mock online supermarket featuring animal-based products (e.g., milk) and their plant-based counterparts (e.g., soy milk). On an iPad, participants ( N = 154) were asked to buy seven items and were told that they would receive some of the products in their final basket and that the indicated prices would be deducted from their monetary compensation. They were divided into two groups: the “swaps” group was shown swap suggestions each time they placed an animal-based product into their shopping basket, and the “no swaps” group was not shown any swap suggestions. Of the 481 swaps, only approximately 2% were accepted, implying that the swap recommendations did not meaningfully impact consumers' choices. These findings indicate that swap recommendations do not guarantee purchase increase of plant-based products in real-world settings and show a lack of consumer willingness to substitute animal-based products with plant-based ones. Our study highlights the need for future research to use high-ecological-validity designs to capture genuine consumer behavior, and the need to improve plant-based products to reduce acceptance barriers. • Only about 2% of swap recommendations were accepted by consumers. • Swap suggestions did not increase plant-based purchases in this study. • Real prices and product consequences could strongly influence nudging effects. • Hypothetical choice tasks may overestimate nudging effectiveness.
Yu et al. (Sun,) studied this question.