Study 1

2.3.1 Method

Study 1 examines whether provision of a relatively low or high CARP decreases or increases the average amount of sugar chosen when a number of breakfast cereals is presented. Sugar was selected as the nutrient being disclosed as its overconsumption can cause severe health problems (World Health Organization 2013). For example, early in their lives children learn that sugar causes tooth decay (Kay and Locker 1996).

Moreover, high intakes of sugar include excessive energy consumption and decreased diet quality (Malik, Schulze, and Hu 2006). Fruit muesli, a German granola-based

23 cereal, was chosen for its wide sugar range–typically most of the available products contain between two and 37 grams sugar per 100 grams muesli.

In our study participants read an introductory text about muesli as a breakfast cereal, its recommended serving size, and the digestion of carbohydrates and sugars (see appendix 1). The CARP was revealed within the text without highlighting or placing particular emphasis on this information. In order to determine a low and high CARP we employed a procedure suggested by Rhine and Severance (1970). As the low CARP we used the approximate middle of the lower half of the total range of sugar values in fruit muesli (10 grams). The upper end of the available sugar range (37 grams) was used for the high CARP (Rhine and Severance 1970). Participants were randomly assigned to one of the two CARP conditions.

To capture sugar choice under realistic settings we conducted a choice-based conjoint (CBC) experiment controlling for additional attributes. This method allows introduction of several product attributes at varying levels. In CBC experiments, participants are asked to choose from a number of alternative products composed of several product attributes (Carroll and Green 1995). In addition to sugar content, we included price, packaging, and organic labeling due to their importance in contemporary food product preference (Briers and Laporte 2013; Chandon and Wansink 2012). The sugar content attribute has six levels covering the whole range of sugar values in the muesli market (2 to 37 grams). The range of possible sugar values was divided into six equidistant levels:

2 grams, 9 grams, 16 grams, 23 grams, 30 grams, and 37 grams. Price has three levels (low, medium, and high): the usual sales price of popular German muesli Dr. Oetker Vitalis, which is 2.99 € (USD 3.72), serves as the medium price. The price range included values 25% below and above that price. This led to the low price of 2.29 € (USD 2.85), which is a common sales price for lower priced mueslis, and 3.69 € (USD 4.59) which is common for more expensive muesli products. The packaging attribute

24 has two levels: plastic bag and container. As for organic labeling the levels include presence versus absence of such a label.

In this experiment, each respondent was presented a sequence of 12 choice sets. Every participant received a particular set of choice tasks. Each choice set consisted of four hypothetical mueslis, comprised of one level of each of the four attributes as well as a no choice option. We used such a decompositional method in order to minimize socially desirable responses that overstress the relevance of sensitive attributes (Carroll and Green 1995; Louviere and Islam 2008). All choice tasks and product combinations presented to participants reflected a D-efficient design (Kuhfeld, Tobias, and Garratt 1994). Appendix 3 displays an exemplary choice task. Respondents were asked to select their most preferred product in each of the 12 choice tasks. We controlled for order effects by randomizing the order of profiles across participants, and we calculated the average sugar choice as the mean of the sugar content across the 12 chosen muesli.

Students from five German universities participated in return for a chance to win an Amazon voucher in a post-survey drawing as well as a guaranteed donation to

“Medicines sans Frontiers” for each completed questionnaire. At the beginning of the experiment, participants were randomly assigned to one of the two experimental conditions (low/high CARP). In order to ensure that only students with sufficient buying experience with respect to the test category were considered, qualifier questions were included at the beginning of the questionnaire. The final data set consists of 211 participants who completed all tasks. Sixty-one percent of the participants were female, and most were between 20 and 30 years old.

25 2.3.2 Results

Hypothesis 1 proposed that the average amount of sugar consumed by participants in the low CARP condition would be lower than the average amount chosen by participants in the high CARP condition. In support of H1, an ANOVA yielded a significant effect for CARP (F(1, 183) = 3.8, p = .05). As predicted, participants in the high CARP group would have consumed more sugar (MhighCARP = 15.8g, SD = 6.7) than those in the low CARP condition (M_lowCARP = 13.9g, SD = 6.6). Figure 1 displays the sugar choice per treatment group.

Figure 1: Average Sugar Consumption

2.3.3 Discussion

Study 1 offers initial evidence supporting the hypothesis that providing consumers with a CARP influences their food choices. We proposed that when consumers are given a high CARP they feel justified to choose high amounts of sugar. This suggests that the

Average Sugar Content (in gram)

low CARP high CARP

26 low CARP did intensify the feeling of guilt when choosing products with high amounts of sugar. Notably, we found these differences across CARP conditions while holding constant other product attributes such as price, packaging and organic labeling. This means that although sugar content was only one of four attributes, the sugar-related reference point affected overall product preferences and choice.

Once we have shown the effect of CARP on choice in study 1, we are interested in the mechanism that leads to changed choices. Hence, in study 2 we will investigate the effect of CARPs on latitude of sugar acceptance.