Appendix A

Question Items of Survey 1

Participants: 1,000 persons
(single men and women in his/her 20s or 30s, age and gender are equally allocated)
Q1. Please answer the following eight items about your personality.
Answer options
1: It does not fit to me at all <- 3: Cannot say either -> 5: It fits to me well
Question items
a. I am cooperative b. I am open in peers c. Others are hard to understand my personality d. I am self-paced and hardly affected by others e. I am thoughtful and take a cautious attitude toward others f. I have an uneven mood and sometimes it looks like a dual personality g. I am optimistic h. I am big-hearted
Q2. Do you think blood type and personality are related?
1: Not related at all 2: A little related 3: Somewhat related 4: Strongly related 5: I don’t know
Q3. Do you know the characteristics and the compatibilities of blood types?
Answer options 1: I don’t know at all 2: I know a little 3: I know some 4: I know well
Q4. Lastly, please tell us your blood type.
1: Type A 2: Type B 3: Type O 4: Type AB 5: I don’t know
Q5. Gender (based on respondent registration information)
1: Male 2: Female
Q6. Age (depending on respondent registration information)
1: Teen or under 2: 20s 3: 30s 4: 40s 5: 50s 6: 60s 7: 70s or over

Question Items of Survey 2

Participants: 2,000 persons
(men and women in his/her 20s to 50s, age and gender are equally allocated)
Q1. Please answer the following eight items on your personality.
Answer options
1: It does not fit to me at all <- 3: Cannot say either -> 5: It fits to me well
Question items
a. Meticulous b. Hard to understand by others c. Self-paced d. Positive e. Dual personality f. Big-hearted g. Self-centered h. Serious i. Cheerful j. Loose k. Genius-like l. Nervous
Q2. For the 12 items in Question 1, please choose one or more blood type(s) that you think will apply to your image.
1: Type A 2: Type B 3: Type O 4: Type AB
Q3. same as Q2 of Survey 1.
Q4. same as Q3 of Survey 1.
Q5. same as Q4 of Survey 1.
Q6. same as Q5 of Survey 1.
Q7. same as Q6 of Survey 1.