Q1. What is the passage mainly about?

1. AHow to teach babies to talk
2. BYoung children help others even without being asked
3. CWhy adults often drop things
4. DHow to choose toys for babies

第1文の問い「頼まれなくても助けるか」に対し、多くの子が自分から助けたという結果を示しているので B。

Q2. How old were the children in the first study?

1. A8 months
2. B12 months
3. C18 months
4. D3 years

Scientists in Germany tested 18-month-old children. とあるので C。

Q3. In this passage, "on purpose" means ...

1. Abecause you want to
2. Bby accident
3. Cvery quickly
4. Dtogether with a friend

on purpose は「わざと、故意に」。反対は by accident（うっかり）。A が正解。入試の熟語問題で頻出。

Q1. Why was the situation where the adult threw an object on purpose important?

1. AIt made the children laugh.
2. BIt showed that the adult was angry.
3. CIt tested how strong the children were.
4. DIt showed that the children helped because they understood the adult's goal.

わざと落としたときはほとんど拾わなかったので、子どもは「物が落ちたから」ではなく、This shows that they understood what the adult was trying to do. なので D。

Q2. Which children helped less in the 2008 study?

1. AChildren who got toys as rewards
2. BChildren who were praised
3. CChildren who got nothing
4. DChildren who were 18 months old

20-month-olds who received toys as rewards for helping later helped less とあるので A。

Q3. What does the passage suggest about children's helping?

1. AIt depends entirely on rewards.
2. BIt seems to come naturally from within.
3. CIt starts only after age five.
4. DIt is taught mainly at school.

頼まれずほめられなくても助け、ご褒美でかえって減ったことから、助けたい気持ちは内側から自然に生まれると推論できるので B。

Q1. Why did the children leave the clothespin on the floor in the control condition?

1. AThey could not reach it.
2. BThe adult had thrown it down on purpose.
3. CThey were afraid of the adult.
4. DNobody had praised them.

When the adult threw the clothespin down on purpose, the children mostly left it on the floor とあるので B。子どもは大人の「果たせていない目標」があるときに手伝った。

Q2. How did the chimpanzees' helping differ from the children's?

1. AThey never helped at all.
2. BThey helped only when rewarded.
3. CThey helped more often than the children.
4. DThey helped in fewer kinds of situations.

but in fewer kinds of situations than the children とあるので D。A は helped too と矛盾。

Q3. According to the overjustification effect, what can an outside reward do?

1. ATurn an act done for its own sake into something done for pay
2. BMake children more creative
3. CIncrease helping in every situation
4. DHelp children learn to talk

in which an outside reward turns something done for its own sake into something done for pay とあるので A。