Public defence: Helena Berz Slapø
Helena Berz Slapø will defend her thesis "The Impact of In-Store Interventions and Delayed Discounting on Food and Beverage Choices in Supermarkets" for the PhD in Behavior Analysis.
Helena Berz Slapø will defend her thesis "The Impact of In-Store Interventions and Delayed Discounting on Food and Beverage Choices in Supermarkets" for the PhD in Behavior Analysis.
The ordinary opponents are:
The leader of the public defense is Department Manager Luiza Freitas Caldas, OsloMet.
The main supervisor is PhD Samira Lekhal, GreeNudge Health AS and Department of preventive medicine, Vestre Viken.
The co-supervisor is Professor emerita Ingunn Sandaker, OsloMet.
Supermarkets play a crucial role in promoting healthier food and beverage choices. Behavioral economics research suggests that dietary decisions can be improved by altering the environment in which choices are made.
This dissertation evaluates the effectiveness of in-store supermarket interventions and explores whether delay discounting—the preference for smaller immediate rewards over larger delayed ones—offers insights into customer decisions in supermarkets.
Study 1, a systematic review with meta-analysis, evaluated the effect size (ES) of in-store interventions in real life supermarkets. Results showed significant improvements in healthy purchasing behavior. Overall ES was d = 0.17 (Cohen’s d), with the largest effects observed for pricing interventions (d = 0.40) and when targeting fruits and vegetables (FVs) (d = 0.28).
Two descriptive studies (Study 2 and 3) examine how real-world supermarkets implemented interventions to increase sales of healthier products. Both studies show observations made in Norway’s largest supermarket chain group, NorgesGruppen.
Study 2 shows how proximity (i.e., placing diet soda first in the customer flow, at eye level in shelves, and as the first option in refrigerators for beverages) is used both on its own and in combination with a price discount (i.e., a 12 percent reduction for diet alternatives) to reduce sales of sugary soda.
The percentage of sugary soda sales fell from 54 percent to 47 percent of total sales after the change in proximity and fell to 41 percent after the pricing intervention was introduced.
Study 3 describes the use of multiple in-store interventions to increase sales of FVs. Interventions include moving the FVs sections, healthy marketing campaigns, reducing price, launching a benefits program, placing FVs at checkout and launching portioned FVs products. Sales of FVs increased 34.1 percent between 2012 and 2020.
In Study 4 a virtual experiment investigated differences in rate of delay discounting between ready-to-eat food, home prepared food, and money. No significant differences were found in discount rates between food types or between food and money.
Overall, the findings highlight the potential of in-store interventions to improve dietary behavior, though further research is needed to refine these strategies and understand food-related decision-making complexities.
The discounting experiment suggests that food type does not significantly influence discounting behavior, underscoring the need for deeper exploration of unhealthy food consumption drivers.