Appendix A
This Appendix provides English translations of the Japanese instructions used in the experiments. It is a modified version of the instructions of Kamijo et al. [
14] with the general public as participants.
Write notes if necessary.
Thank you for participating in today’s experiment. Please do not look at other seats or around in the laboratory. Refrain from private conversations. Do not engage in eye contact, hand gestures, or other forms of communication. Do not touch the computer until instructed to do so. Do not eat or drink. Please raise your hands quietly if you have any questions. Our staff will come to your seat to answer your questions.
Each participant is asked to behave as a person of the future or present generation. Whether you belong to the future or present generation is written on your seat. Based on the information we received from you at reception, we designated those who were relatively old as the present generation and those who were relatively young as the future generation.
Participants are divided by a computer lottery so that there are groups of three participants: one from the future generation and two from the present generation. The computer lottery takes place regardless of the actual parent-child relationship. Each group is independent and does not influence the others. Participants are asked to make decisions regarding resource allocation within their groups. It is not revealed who is in the same group during or after the experiment. Furthermore, the other participants will not be informed of the decisions you made.
The experiment is divided into two halves (Experiments 1 and 2). Experiments 1 and 2 are independent, and the decision-making outcome in Experiment 1 will not affect the content of Experiment 2. Please consider them separately and make decisions accordingly.
Your experimental rewards will be determined according to the decision-making results in Experiments 1 and 2. Specifically, the reward amounts in Experiments 1 and 2 are determined, respectively, based on each decision-making result. After Experiment 2 is completed, a computer lottery selects one of the two amounts as your reward for today’s experiment. The final reward will be the amount selected plus 500 yen as a participation fee. Participants under 15 years of age receive a book card or a set of book cards and sweets as a reward, equivalent to the final monetary reward.
In Experiment 1, the distribution of 2000 yen between the present and future generations is determined. One of the following is determined by the vote of the present generation:
Proposal 1 (present generation 1400 yen; future generation 600 yen);
Proposal 2 (present generation 1000 yen; future generation 1000 yen);
Proposal 3 (present generation 600 yen; future generation 1400 yen).
Two thousand yen will be distributed according to the proposal with the most votes.
Each person of the present generation has one vote. They may only vote for a single distribution proposal. In the case of a tie for first place, a computer lottery determines the outcome.
The monetary amount of each distribution proposal represents the amount of each person’s rewards for each generation. For example, if distribution proposal 1 is selected by voting, each participant of the present generation will receive a reward of 1400 yen, and the future-generation participant will receive a reward of 600 yen. The same applies to the other distribution proposals.
People from the future generation do not make decisions. Please wait for the present generation’s decision-making.
The voting results of Experiment 1 are not disclosed when Experiment 1 is completed. This will be disclosed when Experiment 2 is completed and the rewards are determined.
The following pages explain the computer screens and their operations.
Figure A1.
Start screen for Experiment 1.
Figure A1.
Start screen for Experiment 1.
To begin, you will see the above screen. Here, you will be informed of whether you belong to the present or future generation. It also displays the number of people in the present and future generations. In this example, you are a person of the present generation.
The remaining time (s) is displayed in the upper right of the screen. The screen proceeds automatically after 2 min. People of the present generation should consider which proposal they should vote for.
Figure A2.
Decision-making screen for the present generation.
Figure A2.
Decision-making screen for the present generation.
The present generation’s decision-making takes place on a screen, as shown above. Please click on the button marked “1” to vote for proposal 1, the button marked “2” to vote for proposal 2, or the button marked “3” to vote for proposal 3. Once a decision is made, it cannot be reversed.
The above screen appears while waiting for other participants’ decision-making or experimenters’ operations. We apologize for the delay; it is only a few minutes long at most, so please be patient. After all the people of the present generation complete their decision-making, the explanation of Experiment 2 begins promptly.
The decision-making content in Experiment 2 is almost identical to that in Experiment 1. The distribution of 2000 yen between present and future generations will be determined. One of the following is determined by the vote of the present generation:
Proposal 1 (present generation 1400 yen; future generation 600 yen);
Proposal 2 (present generation 1000 yen; future generation 1000 yen);
Proposal 3 (present generation 600 yen; future generation 1400 yen).
Two thousand yen will be distributed according to the proposal with the most votes.
Unlike Experiment 1, one of the two people in the present generation can cast two votes in Experiment 2. If you have two votes, please cast one vote for yourself and the other on behalf of the future generation that cannot participate in the vote. You are free to decide how to cast these two votes. You may not receive compensation from future generations even if you vote as a proxy.
The following pages explain the computer screens and their operations.
Figure A4.
Start screen for Experiment 2.
Figure A4.
Start screen for Experiment 2.
To begin, you will see the above screen. Here, you will be informed of whether you belong to the present or future generation. It also displays the number of people in the present and future generations. It also displays whether one or two votes were received. In this example, you are a person of the present generation who has two votes.
The remaining time (s) is displayed in the upper right of the screen. The screen proceeds automatically after 2 min. People of the present generation should consider which proposal they should vote for.
Figure A5.
Decision-making screen 1 for the present generation.
Figure A5.
Decision-making screen 1 for the present generation.
The present generation’s decision-making takes place on a screen, as shown above. This screen is the same as that used in Experiment 1.
Figure A6.
Decision-making screen 2 for the present generation.
Figure A6.
Decision-making screen 2 for the present generation.
The present generation with two votes casts a second vote on behalf of the future generation on a screen, as shown above. The decision-making process is the same as before.
Figure A7.
Result screen.
Figure A7.
Result screen.
After all the selections in Experiment 2 have been made, the voting results for Experiments 1 and 2 are displayed as shown above. It also shows the result a computer lottery has selected to determine your reward. The final reward for the experiment, including the 500-yen participation fee, will also be displayed.