Experimental Design
This lab experiment will compromise three different treatments:
- Control group: It is composed of two rounds. In the first round, subjects are endowed with €10 and should decide how much to keep for themselves and how much to donate to an NGO. The chosen NGO is called "Reforesta", which is dedicated to the promotion of sustainable development and contributes to the fight against desertification through the planting of trees. "Reforesta" plants and cares for a tree for each €15 it receives. Given that a tree is able, on average, to absorb 20 kg of CO2 per year and that 1 kg of CO2e equals 4,02 km of driving a gasoline car, subjects are informed that for each euro they donate to Reforesta they can save the equivalent to 5.36 kms of driving a gasoline car. When entering a potential donation, subjects can always observe how many kms of riding a gasoline car they are saving. After all the subjects have made the decision, they are asked to guess how much they think is the average donation in the session. This decision is elicited through a scoring rule in which subjects can get at most €2. Then subjects move to the second round in which they have to make the same two tasks as in the first round. After the second round, subjects have to answer a non-incentivized questionnaire asking them several questions regarding their sociodemographic background, social norms, and relationship with the environment. For the payment, the computer randomly chooses between the payoffs of the first and the second round (the sum of what they have kept for themselves and the money earned in the elicitation of beliefs).
-Information group: Everything is the same as in the Control group except for the fact that when facing the donation in the second round, subjects are informed about the mean contribution of their group in the first round.
-Normative group: Everything is the same as in the Control group except for the fact that when facing the donation in the second round, subjects are informed about how many kilometers would have been saved if everyone in the session had made exactly the same donation as him/herself in the first round.
The donations will be actually transferred to the NGO and subjects will be able to verify that this is the case (by means of an NGO certificate).
The full protocol guarantees the anonymity of the subjects. The process works as follows
1. Subjects have an envelope on the terminal and a piece of paper
2. Subjects write the pseudonym (4 letters and two numbers) chosen by themselves both on the outside of the envelope and on the piece of paper
3. The piece of paper with the pseudonym is kept by each participant
4. An experimenter takes all the envelopes (checking that they have written the pseudonym) to the room where the payments will be made
5. After the experiment, the experimenter responsible for the payments introduces the money that each subject has earned, as well as the receipt with the amount received in the envelope (based on the pseudonym).
6. When all the envelopes have been filled, a randomly chosen student hands out the envelopes to the participants (participants show him their pseudonym before receiving the envelope).
7. Participants withdraw the money and fill in the rest of the receipt (real name, address, ID, signature,...).
8. When all the envelopes are in the box, the box is taken to the FUEIB (a randomly chosen student accompanied by an experimenter).
9. After running the last session, the researchers will transfer the funds to the NGO and publish a list with the total amount donated and the individual contribution made by each participant (using their anonymous pseudonyms).