We will randomly assign each participant to one of six conditions. These conditions are the treatment groups A-D (described below) plus a control condition and a placebo condition.
Participants in the control condition will read text that describes the role of food in everyday life and no additional text. Participants in conditions A-D will read additional text that will be specific to the condition. The subjects in the placebo group will read a text unrelated to food; specifically, it will be a text about the importance of breathing clean air.
Additional text participants will read in conditions A-D:
A. Provide subjects with (factual) “social information” about dietary choices of the population, for example “thousands of people are adopting a plant-based diet”.
B. Put subjects in a “loss domain” state, with text that cites the average number of animals that die each year as a result of an individual eating a non-plant-based diet.
C. Put subjects in a “gain domain” state, with text that cites the average number of animals’ lives that an individual can save each year by adopting a plant-based diet.
D. Sentience/sapience/morality: Highlight animals’ ability to feel pain, and the fact that many standard farming practices inflict pain.
Next we will assess whether the provision of specific information affects opinions about eating animal-derived products. Within a set of general questions about attitudes, we will ask participants to indicate if a sentence like “If the taste and texture were identical to beef, I would be likely to eat a vegetarian burger” applies to them. This simple design will provide us with immediate self-reported information about whether attitudes change in the different conditions. The advantage of simplicity comes with the cost that the results would be based on “stated” rather than “revealed” preferences. Given also the nature of the question of interest, demand effects and social desirability biases are possible. This concern, however, is unlikely to be severe in our case because we are interested not only in the difference between the treatments and the control, but also in the differences between each of the individual treatments. To the extent that demand effects and social desirability biases are present in all conditions, looking at the differences would help “net out” this potential confound.
In addition to the above-described research questions, we will have all study participants complete the “Big Five” personality markers (Gosling, S. D., Rentfrow, P. J., & Swann, W. B., Jr. (2003). A Very Brief Measure of the Big Five Personality Domains. Journal of Research in Personality, 37, 504-528). Including these types of questions will help us determine whether key variables of interest regarding changes in dietary choice correlate with personality measures.
The main hypothesis that we are testing is whether the behavioral interventions and/or the provision of morality-based information leads to more aversion toward eating animal products. However, we may find different results. For example, views and habits with respect to diet tend to be stable and, we may find participants are impervious to information focused on eliciting moral concerns. Alternately, individuals may even resist information which conflicts with their baseline belief that their diet is morally acceptable, and perhaps cognitive dissonance or some other mechanism may cause them to become further entrenched in their current beliefs and behavior.
To test our hypotheses, we will examine whether there are differences across conditions in the attitude and behavior measures we include in the study.
To screen out invalid responses, we will have 3 coders go through participants' summaries of the message they just read and indicate (yes/no) whether they believe the participant has shown evidence that he/she read the assigned message. If all 3 coders unanimously agree that a participant has not shown evidence of having read the assigned message, then that participant will be removed. Otherwise, the participant will be included in all analyses.
UPDATE ABOUT ADDITIONAL INTERVENTION (APRIL-MAY 2019)
We are adding a second study with a similar structure to the original one, in order to test the impact on stated eating preferences of appeals to different moral values. We will have the following experimental conditions:
Control: Participants in this condition will be assigned a short reading with generic information of the eating habits of people and their average daily calorie intake requirements.
Placebo: Participants will be assigned a short reading not related to eating or food.
Harm/care and suffering condition: Participants will receive a reading in which the first paragraph is the reading assigned in the control condition. A second paragraph will describe how animals perceive pain, and the fact that many farming practices do inflict pain upon animals.
Harm/care and environment condition: Participants will receive a reading in which the first paragraph is the reading assigned in the control condition. A second paragraph will state that a diet without meat and dairy has a much smaller impact on the environment.
Fairness/reciprocity condition: Participants will receive a reading in which the first paragraph is the reading assigned in the control condition. A second paragraph will state that the treatment of animals should follow the same principle of fairness extends to all individuals regardless of their skin color, nationality, height, age, species, and so on.
Loyalty/patriotism condition: Participants will receive a reading in which the first paragraph is the reading assigned in the control condition. A second paragraph will state that eating animal products can be considered unpatriotic because of the environmental impact of animal farming and because respecting animals is part of the national identity.
Authority/respect condition: Participants will receive a reading in which the first paragraph is the reading assigned in the control condition. A second paragraph will state that the current amount of consumption of animal product is much higher than any other previous historical period, and as such, it is out of step with historical roots and traditions.
Sanctity/purity condition (life/religion/spirituality): Participants will receive a reading in which the first paragraph is the reading assigned in the control condition. The second paragraph will state that many mainstream religions imply respect for animals, too.
Sanctity/purity condition (Disgust): Participants will receive a reading whose first paragraph is the reading assigned in the control condition. A second paragraph will describe how disgusts is a reason for why certain people do not eat meat.
In each condition, participants will receive a comprehension question about the text they just read.
We will then add to the survey a Moral Foundation questionnaire, questions about attitudes toward the consumption of animal products (one our main outcomes of interest), and a “donation” question: We will ask participants to split $10 between two non-profit organization, one that is animal-focused (it conducts investigations of factory farms and presses for stronger legal protection for animals), and one that is human-focused (it promotes youth empowerment and encourages young people to be engaged in society). We will randomize the order in which we will list the two organizations. We will inform the participants that we will randomly select 100 of them and implement their allocation choices with an actual donation. The donation decision will represent our second outcome of interest. We will conclude with a socio-demographic and moral identity questionnaire.
The full survey is attached