Appendix 1: Experimental instruction
These are the experimental instructions for the
NoInfo treatment (translated from the German language). The instructions for
Info-Sunk and
Info-NoSunk are very similar.
Welcome to the experiment and thank you for your participation!
General instructions
In this experiment you can earn money. Your payment will be determined by the course of the game, which means that it depends on your own decisions and on the decisions of your co-players. Now carefully read the following rules of the game. If you have questions, please raise your hand. We will come to you and answer your questions.
All decisions in this experiment are anonymous. For the payment of your earnings you will have to sign a receipt. The receipts are needed only for billing and accounting. However, under no circumstance will we connect your names with the decisions in the experiment.
Important rules:1.
From our side: NO DECEPTION. We promise that this experiment will be conducted exactly as described in these instructions. This is the rule for all experiments that are conducted in K-Lab. We can publish our results only when we follow this rule consistently and under all circumstances.
2.
From your side: NO COMMUNICATION. Please do not communicate with other participants during the experiment and take your decisions individually. Your mobile phones and other communication devices must be switched off during the entire experiment. The experiment will run at computers. You are only allowed to use those features of the computer that are needed for the course of the experiment. Communication with other participants, the use of mobile phones and the use of other functions of the computer than those required for the experiment lead to exclusion from the experiment and the loss of all earnings.
Part 1
The experiment consists of two parts. These are the instructions for Part 1. You will receive the instructions for Part 2 as soon as Part 1 is concluded. The two parts of the experiment are independent from each other. Your earning from both parts will be paid to you in cash right at the end of the experiment. The payment will made in private such that no other participant can see how much you have earned. After the experiment you will be asked to answer a short questionnaire.
Your earnings in Part 1 depend only on your individual decisions. The decision table below shows ten decisions. Every decision is a choice between “Option A” and “Option B”. You will make the ten decisions at the computer and document them by clicking either on “Option A” or on “Option B”. Before you made the ten decisions, please take a look at how exactly these decisions influence your earnings.
1 | With 1/10 Probability: 2.00 Euro; | With 1/10 Probability: 3.85 Euro; |
| With 9/10 Probability: 1.60 Euro | With 9/10 Probability: 0.10 Euro |
2 | With 2/10 Probability: 2.00 Euro; | With 2/10 Probability: 3.85 Euro; |
| With 8/10 Probability: 1.60 Euro | With 8/10 Probability: 0.10 Euro |
3 | With 3/10 Probability: 2.00 Euro; | With 3/10 Probability: 3.85 Euro; |
| With 7/10 Probability: 1.60 Euro | With 7/10 Probability: 0.10 Euro |
4 | With 4/10 Probability: 2.00 Euro; | With 4/10 Probability: 3.85 Euro; |
| With 6/10 Probability: 1.60 Euro | With 6/10 Probability: 0.10 Euro |
5 | With 5/10 Probability: 2.00 Euro; | With 5/10 Probability: 3.85 Euro; |
| With 5/10 Probability: 1.60 Euro | With 5/10 Probability: 0.10 Euro |
6 | With 6/10 Probability: 2.00 Euro; | With 6/10 Probability: 3.85 Euro; |
| With 4/10 Probability: 1.60 Euro | With 4/10 Probability: 0.10 Euro |
7 | With 7/10 Probability: 2.00 Euro; | With 7/10 Probability: 3.85 Euro; |
| With 3/10 Probability: 1.60 Euro | With 3/10 Probability: 0.10 Euro |
8 | With 8/10 Probability: 2.00 Euro; | With 8/10 Probability: 3.85 Euro; |
| With 2/10 Probability: 1.60 Euro | With 2/10 Probability: 0.10 Euro |
9 | With 9/10 Probability: 2.00 Euro; | With 9/10 Probability: 3.85 Euro; |
| With 1/10 Probability: 1.60 Euro | With 1/10 Probability: 0.10 Euro |
10 | With 10/10 Probability: 2.00 Euro; | With 10/10 Probability: 3.85 Euro; |
| With 0/10 Probability: 1.60 Euro | With 0/10 Probability: 0.10 Euro |
At the end of the experiment the computer will randomly generate two numbers between 1 and 10. The first number determines which of the ten decisions will be used for payment. The second number determines the earnings from the option you chose: A or B. That means that although you make ten decisions, only one will be used for payment. Every single decision has the same chance of being drawn. Since you do not know in advance which decision will be drawn, you should make every decision as if it determines your payment.
Please look at decision 1 in the table. Option A provides a gain of 2.00 Euro if the random number is 1 and a gain of 1.60 Euro if the random number is 2–10. Option B provides a gain of 3.85 Euro if the random number is 1 and a gain of 0.10 Euro if the random number is 2–10. The other decisions are similar, whereby the chances for a higher gain rises as you go further down in the table. For the decision number 10 in the last raw of the table the second random number is not needed since the probability for the highest gain is one. Thus, the decision is between 2.00 Euro in Option A and 3.85 Euro in Option B.
In summary, you will make ten decisions of which only one will be used for payment at the end. For each decision in the table, you must choose between Option A and Option B. When you are done, click “Next”.
You will learn the two computer generated random numbers and your gain in Part 1 only after completing Part 2.
Part 2
In Part 2 you are a member of a group of five players. That means that apart from you there are four other players in your group. Each player faces exactly the same decision problem. Each player receives 55 Taler. You will see these Taler in your private account displayed on the top-right corner of your computer screen. In the game, you will decide whether you want to contribute your Taler to a common project. It is possible to contribute any integer amount from 0 to 55 Taler. The Taler that you do not contribute to the common project remain in your private account.
If the group contributes in total
125 Taler or more to the common project, then every player in the group receives a
bonus of 50 Taler. This bonus is then added to the Taler remaining in the private account, regardless of how much a player contributed to the common project. Your profit in this case is:
$$\begin{aligned} {{\varvec{Your\, profit\, = \,Remaining\, Taler\, in\, private\, account\, +\, 50\, Taler}}} \end{aligned}$$
If the group contributes in total
124 Taler or less to the common project, then there is no bonus. Your profit in this case is:
$$\begin{aligned} {{\varvec{Your\, profit\, =\, Remaining\, Taler\, in\, private\, account}}} \end{aligned}$$
Below we describe a few numerical examples.
Example 1: Suppose that the other four players in your group contribute in total 80 Taler to the common project. If you contribute 10 Taler, your payoff is 45 Taler (= 55 − 10). If you contribute 25 Taler your payoff is 30 Taler (= 55 − 25). If you contribute 45 Taler your payoff is 60 Taler (= 55 − 45 + 50).
Example 2: Suppose that the other four players in your group contribute in total 100 Taler to the common project. If you contribute 10 Taler, your payoff is 45 Taler (= 55 − 10). If you contribute 25 Taler your payoff is 80 Taler (= 55 − 25 + 50). If you contribute 45 Taler your payoff is 60 Taler (= 55 − 45 + 50).
Example 3: Suppose that the other four players in your group contribute in total 120 Taler to the common project. If you contribute 10 Taler, your payoff is 95 Taler (= 55 − 10 + 50). If you contribute 25 Taler your payoff is 80 Taler (= 55 − 25 + 50). If you contribute 45 Taler your payoff is 60 Taler (= 55 − 45 + 50).
Please notice the following important rules of the game. The game will be played over two stages. Your contribution to the common project is the sum of your contribution in Stage 1 and your contribution in Stage 2. If, for example, you contribute 5 Taler in Stage 1 and 10 Taler in Stage 2, then your contribution to the common project is 15 Taler.
In Stage 1 you can contribute to the common project any integer amount from 0 to 55 Taler. After all players have chosen their contributions in Stage 1, the individual contributions of all players in Stage 1 as well as the sum of all contributions in Stage 1 will be shown on the computer screen. The own contribution for each player will be shown in boldface.
In Stage 2 there are two options. The computer decides randomly which of the two options realizes for your group, while each option has equal chance. In Option 1 it is only possible that you leave the current contribution unchanged or you contribute more Taler to the common project. In Option 2 it is possible that you leave the current contribution unchanged, that you contribute more Taler to the common project or that you withdraw from your contribution make in Stage 1. If you want to contribute more Taler, any contribution from 0 to the remaining funds in your private account is possible. You will see the funds remaining in your private account displayed in the upper-right corner of the computer screen. If you want to withdraw (and this is possible) from the contribution made in Stage 1, you must enter a negative value as your contribution in Stage 2. For example, if you want to withdraw 5 Taler, then you must enter − 5 in the entry field. You can only withdraw maximum as many Taler as you contributed in Stage 1. The withdrawn Taler will be added back to your private account.
On the computer screen it will be shown which of the two options in Stage 2 is realized for your group. Please note that in Stage 1 you do not know yet which of the two options will be realized. You will only learns this at the beginning of Stage 2. The realization of the option is valid for the whole group. This means that either all players in your group can withdraw the previously made contributions or nobody in your group can do this.
After all players have made their contributions in Stage 2, the individual contributions of all players in both stages as well as the sum of all contributions in both stages are displayed on the screen. The own contribution will be shown in boldface for each player. Note that the group as a whole must contribute at least 125 Taler to the common project over both stages such that the bonus is realized for all players.
The Taler earned in the experiment will be converted in Euro. You will receive 1 Euro for every 5 Taler (0.20 Euro per Taler). If, for example, you earn in total 60 Taler, then you receive 12 Euro.
Before the game in Part 2 begins, we would like to ask you to answer a few control questions at the computer. This way we can make sure that all participants have understood the rules of the game. If you have questions, please raise your hand. We come to you and answer the questions.
After answering the control questions, there will be four trial rounds, in which you can try out the game. The trial rounds are not relevant for your payment. Please note that in these trial rounds your four co-players will be played by the computer. Therefore, you cannot draw any conclusions about the behavior of your future co-players.