Experimental Design Details
Experimental Design Details
First, through MyVoice.com Ltd., an online survey company in Japan, we conduct a screening survey and collect 7,200 Japanese people who are not from Fukushima. They must be unmarried 20s to30s or parents who have unmarried 20s to30s son or daughter.
Second, we conduct the main experiment with respondents of the screening survey and collect 5,040 responses. We randomly assign the 1,680 respondents to one of the following three groups:
Treatment A: We provide scientific information, as presented by scientific and medical institutions, indicating that there are unlikely to be any future health effects from radiation.
Treatment B: We provide social information that more than 70% of those who know someone in Fukushima or those who consume food from Fukushima express that there is unlikely to occur radiation-induced health problems for the future generations.
Control: We provide no additional information.
The participants are asked to join financially incentivized two dictator games in both of Anonymous and Fukushima conditions, i.e., Unmarried joins (I, III), and Parent joins (II, Ⅳ). We provide the information depend on the treatments before the participants join the game under Fukushima condition. The final group composition is Treatment A1 (I, III), Treatment A2 (II, Ⅳ), Treatment B1 (I, III), Treatment B2 (II, Ⅳ), Control 1 (I, III), Control 2 (II, Ⅳ).
In the dictator game experiments, we firstly present, as priming, the marriage-related questions, including whether they want to marry for Unmarried group, or whether they want their son/daughter to marry for Parent group. We then present a dictator game two times as in the procedure above. In each game, participants are given an endowment of 100 Japanese yen in addition to the participation fee. They are also asked to decide how much of the 100 yen they give to a paired other person. Participants are informed that the paired person is not participating in this same survey, that the participant solely determine the allocation, that they are the only one who can give a share of the money to the paired person, and that after the experiment, one of the two experimental responses will be randomly selected to carry out that allocation.
Before and after the experiments, we set questions to ascertain social characteristics, and beliefs of radiation stigma, science or marriage. Specifically, the radiation-related or marriage-related questions include the followings:
- Do you think that health problems, due to radiation in the affected areas of Fukushima Daiichi Nuclear Power Plant accident, will happen in the future? (4-point scale)
- Do you think that health problems, due to radiation in the affected areas of Fukushima Daiichi Nuclear Power Plant accident, will extend to the future generations? (4-point scale)
- Whether you want to marry someone who lived in Fukushima on 11th March 2011? (5-point scale)
- Whether you allow their children to marry someone who lived in Fukushima on 11th March 2011? (5-point scale)
Thirdly we conduct a follow up survey with respondents of the main survey and collect 3,600 responses, assuming 70% withdrawal rate. In the survey we first present the marriage-related questions, same as above. Then, the participants in all the three groups join one dictator game experiment in the Fukushima condition (III) or (IV) without any treatment information. After the experiment, we provide treatment information as in the procedure above. We then present another incentivized dictator game in the Fukushima condition (III) or (IV) again.