Q1. What is the passage mainly about?

1. AHow to paint like Klee
2. BWhy boys like art
3. CHow a simple group label made boys favor their own group
4. DHow to win a game with points

画家の好みという単純なラベルでグループ分けしただけで、自分のグループをひいきした、という研究の話なので C。

Q2. How were the boys divided into groups?

1. ABy their age
2. BBy the painters they were linked to
3. CBy their test scores
4. DBy their home towns

the boys were put into two groups, one for each painter とあるので B。

Q3. In this passage, "favor their group" means the boys ...

1. Atreated their own group better
2. Bleft their group
3. Cdid not care about their group
4. Dpainted pictures for their group

favor は「ひいきする・優遇する」。自分のグループを特別によく扱ったという意味なので A。

Q1. What did Tajfel want to find out?

1. AWhich painter boys liked better
2. BHow much money boys wanted
3. CWhy children wear T-shirts
4. DThe minimum needed for people to start favoring their own group

第1文の問い What is the minimum needed for people to start favoring their own group? を調べようとしたので D。

Q2. What surprising choice did many boys make?

1. AThey gave all their points to the other group.
2. BThey chose options that made the difference between the groups larger.
3. CThey refused to give any points.
4. DThey kept all the money for themselves.

many even chose options that made the difference between the groups larger とあるので B。

Q3. What can we infer from the 2011 study?

1. AGroup favoritism appears only in teenagers.
2. BGroup favoritism can appear even in young children.
3. CChildren do not care about colors.
4. DOnly boys show group favoritism.

偶然Tシャツの色で分けられた5歳児にも同じ行動が見られたので、幼い子どもにも内集団びいきが現れると推論できる。B。

Q1. Why are Tajfel's results considered surprising?

1. ABecause the boys had known each other for years
2. BBecause the groups were based on serious conflicts
3. CBecause favoritism appeared even though the groups had no history, activity or conflict
4. DBecause the boys gained a lot of money for themselves

The groups had no history, no shared activity and no conflict of interest ... yet most favored members of their own group とあるので C。

Q2. What did the 2014 meta-analysis confirm?

1. APeople cooperate more with ingroup members, especially when they expect something in return.
2. BPeople never cooperate with others.
3. CChildren are more generous than adults.
4. DGroup labels have no effect on behavior.

people cooperate more with ingroup members, especially when they expect something in return とあるので A。

Q3. Which point does the author make in the final sentence?

1. AThe boys always chose to maximize the difference.
2. BThe study proves that people hate outsiders.
3. CTajfel's study should be ignored.
4. DFavoring one's group is different from hostility toward outsiders, and fairness also mattered.

配分は公平さにも引っぱられ、差の最大化が常に優勢ではなかったこと、内集団びいきは外部への敵意と同じではないことを述べているので D。