Experimental Design Details
In our laboratory experiment, participants have the opportunity to receive information in the form of a 360° video on living conditions of pigs in industrial livestock farming. We elicit the demand for information by asking people to decide between two options: (i) watching a 360° video about industrial livestock farming of pigs or (ii) watching a virtual reality tour through the office building of the "Deutsche Bundesbank" (German Central Bank), which they have already watched before. Subjects face eleven choice tasks which differ in the extent to which one of the two videos is incentivized (we randomize which video is denoted as option A). The implied prices of information are -8, -5, -3, -1, -0.5, 0, 0.5, 1, 3, 5, 8 EUR. One decision is randomly selected and implemented (the implied prices of -8 and 8 EUR are each selected with a probability of 27.5 percent, while all other decision are selected with a probability of 5 percent). With the wide range of prices we try to achieve that subjects do not prefer one video option over the other for all relative prices. As a result, all subjects have a positive probability of (not) receiving the information (which allows to estimate e.g. the average treatment effect of information by propensity score weighting).
In the last part of the laboratory experiment, subjects have the chance to win a voucher for the main canteen at the University of Mannheim (with 50 percent probability). They can choose which of two vouchers they would like to receive if they win (the order is randomized): a voucher for menu 1, which usually contains meat (or fish), or a voucher for the vegetarian menu. This decision is used to measure the short run effect of information. To give subjects a better idea of the options, we provide the exact meals that correspond to the vouchers for a sample week (21.10.19–25.10.19). Each voucher has a value of €3. Whether a subject wins or not is determined by a random draw (by the computer) and is independent from the lottery outcome of other subjects. At the end of the experiment, subjects are informed about the lottery outcome and their overall reward. The monetary reward from the experiment is not paid in cash but transferred onto the ecUM (electronic card Universität Mannheim). The ecUM serves as student card at the University of Mannheim and can be used to purchase products in the canteens or other products like the six-month student transit pass. Subjects need to activate the credit on their ecUM by visiting the information counter of the “Studierendenwerk Mannheim”, which is in the same building as the main canteen. The credit is available from Tuesday in the week after the experimental session onwards. Before leaving the laboratory, subjects receive an envelope that contains information on their credit and the corresponding voucher if they have won.
The experimental data is supplemented by data on subjects’ meal purchases made in the period 01.08.2019–31.05.2020 at the canteens of the “Studierendenwerk Mannheim”. The data will be provided by the “Studierendenwerk Mannheim”. The purchases are made with the ecUM. As subjects provide their ecUM number during the experimental session, the purchases can be assigned to a particular subject. Although it is possible to pay in cash at the canteens, the student discount is conditional on paying with the ecUM and few transactions are actually made in cash. For a sample period from 01.10.2019 till 31.10.2019 less than two percent of the transactions in the main canteen were made in cash. We obtain informed consent of subjects to access their data prior to the experimental sessions. The data on meal purchases outside the laboratory is used to measure the long run effect of information.
“[The following paragraph was added on 14.01.2020]
Additional to the sessions at the mLab (Mannheim Laboratory for Experimental Economics), we also run experimental session at the BonnEconLab (Laboratory for Experimental Economics at the University of Bonn) to achieve our desired sample size. The experimental design is the same, except for the following differences:
First, the two vouchers subjects can choose from are not for a whole menu but for a main dish. In particular, subjects can choose from (i) a voucher for a vegetarian main dish (“Vegetarische/Vegane Hauptkomponente”) and (ii) a voucher for a non-vegetarian main dish (“Fleisch/Fisch Hauptkomponente”). The voucher can be used at two different canteens. To give subjects a better idea of the options, we provide the exact meals that correspond to the vouchers for a sample week at one of the canteens. The value of a voucher depends on the particular main dish it is used for. For students, the prices of the main dishes usually vary from €1.35 to €2.05.
Second, the monetary reward from the experiment is transferred onto the Mensa-Card which is used to make noncash payments at the university canteens. Only students with a Mensa-Card are able to participate in the experiment. Subjects need to activate the credit on their Mensa-Card in one of two canteens. The credit is available from Monday in the second week after the experimental session onwards.
Third, the experimental data is supplemented by data on subjects’ meal purchases made in the period 01.10.2019–19.07.2020 at the canteens of the “Studierendenwerk Bonn”. The purchases are made with the Mensa-Card. As subjects provide the number of their Mensa-Card during the experimental session, the purchases can be assigned to a particular subject.”