We investigate if consumers value a socially or an environmentally sustainable production of goods more by measuring the increase in their willingness to accept (WTA) for backpacks when they are either only informed about the social sustainability-related aspects in the production or only about the environmental sustainability-related aspects. WTA are elicited by using an Becker-DeGroot-Marschak auction (BDM) (Becker, DeGroot, & Marschak, 1964). More precisely, participants are given a backpack that they can immediately sell back in two BDM auction rounds. After inspecting the backpack, participants state their minimum selling price in a first pre-intervention auction round. Then, they are given information about functionality and wearing comfort of the backpack, e.g., being water-repellent. In addition and depending on the treatment, participants either receive information about social (SCL) or about ecological (ECO) sustainability. In a second post-intervention auction round, they are then again asked to state their minimum selling price. Subsequently, a number is randomly drawn to be the price. If participants’ bid is higher than the price, they keep the backpack. If their bid is equal to or lower than the price, they must sell the backpack at the drawn price.
The experiment is conducted at university campuses in Cologne. The experimenter asks people that pass by the experimenter’s stand if they want to participate in a consumer survey that is conducted by the University of Cologne. They are told that, if they are drawn in a lottery, they can win a backpack or money. If they agree to participate, they are randomly allocated to either the control or the sustainability treatment. Then, participants are given detailed, written instructions that are read aloud to them by the experimenter. To test and enhance participants’ comprehension of the method, one training round with an apple is conducted. Then, participants make their pre-intervention bid. The backpack is available at the experimenter’s stand for participants to inspect. Afterward, depending on the treatment, participants receive one of two different informational sheets about the backpack, either with social sustainability-related information or with ecological sustainability-related information. Then, participants make their post-intervention bid. In the end, participants answer various questions: They are asked if they know the brand (yes/no) and its CSR activities (5 point Likert scale), if they like the design (5 point Likert scale), about their current need of a backpack (5 point Likert scale) and how well they know the backpack market (5 point Likert scale). Then, they are asked to answer demographical questions about gender, age, vocational situation, field of studies, and highest educational degree. Finally, they are asked if they usually buy socially and environmentally sustainable clothes and accessories (2 questions: 5 point Likert scale) and if they have paid more in the past for clothes and accessories that were produced socially and environmentally sustainably (2 questions: 5 point Likert scale). Participants that are allocated to the sustainability treatment are asked additionally if they know Fair Wear Foundation and bluesign (2 questions: yes/no).