東海大学英語2012年第1問
If you look at the skeletons of many different animals, including humans, you may notice similarities among them. This is because they have a common ancestor. At different points in time, though, this ancestor (1)evolved into many different species. This evolution is easy to see in skeletons; it is more difficult to know when and how less visible traits like human morals evolved. Recent research, however, is shedding light on this.
Dr. Keith Jensen has compared the behavior of chimpanzees to humans in what is called the Ultimatum Game. In this two-player game, one player divides up a reward into two parts. For example, 1000 yen may be split 500 yen-500 yen, or 800 yen-200 yen. The second player can accept the split, in which case both players receive their share. If the player rejects the split, neither player receives anything. Humans usually reject offers of 20% or less of the total amount. If thinking practically, purely according to self-interest, humans should accept any non-zero offer because these players would still gain something. In this situation, though, humans tend to (2)operate out of a sense of fairness, rejecting any offer they think is unfair. When Jensen tried the Ultimatum Game with chimpanzees, the results were quite different. The chimpanzees, acting out of self-interest, accepted nearly all offers greater than zero. They did not appear to have a sense of fairness.
Morals are controlled by the brain. Other research is showing which parts of human brains are involved with a sense of fairness, which presumably distinguish us from chimpanzees. Dr. Alan Sanfey studied humans playing the Ultimatum Game to find out which parts of the brain were used during the game. Brain activity was found in three areas. The bilateral anterior insula*1 was strongly activated with rejected offers. This part of the brain is often associated with strong negative emotions, such as anger and hatred. The dorsolateral prefrontal cortex (DLPFC)*2, which is associated with achieving goals (like obtaining a reward), was activated with all offers. ( A ), the anterior cingulate cortex (ACC)*3, which is connected with cognitive conflict (as when having difficulty deciding what to do), was also activated when offers were rejected. These parts of the brain have a role in 'allowing' humans to reject unfair offers.
A final study focused on the role of the DLPFC in the Ultimatum Game. Dr. Daria Knoch's study confirmed the importance of the DLPFC. She and her team used low-frequency magnetic waves to disrupt activity here and see how the disruption affected the game. When the right side of the DLPFC was disrupted, players accepted even extremely unfair offers. Interestingly, however, those players still considered the offers unfair. (i)They just did not behave in the socially expected way. This finding is similar to (3)observations of patients whose right DLPFC is injured. These people can make appropriate judgments but have difficulty behaving in socially accepted ways. (4)They often appear overly selfish, (5)for instance.
Numerous studies of human evolution and of the brain in particular, are ongoing. There are clear differences between humans and chimpanzees in behavior regarding fairness. The studies mentioned here provide clues as to how the human mind operates. Perhaps the next step is to investigate the minds of chimpanzees as well. Do chimpanzees understand the concept of fairness even though they behave in a selfish, practical way?
- *1 bilateral anterior insula 大脳の内側にある部位
- *2 dorsolateral prefrontal cortex (DLPFC) 前頭前野背外側部、背外側前頭前野
- *3 anterior cingulate cortex (ACC) 前帯状皮質
- 問1 According to the second paragraph, the minimum offer that a human player in the Ultimatum Game would accept is just over .
- ア. 0%
- イ. 20%
- ウ. 50%
- エ. 80%
- 問2 According to the third paragraph, which parts of the brain become active when people reject unfair offers?
- ア. the bilateral anterior insula and anterior cingulate cortex, but not the dorsolateral prefrontal cortex
- イ. the dorsolateral prefrontal cortex and anterior cingulate cortex, but not the bilateral anterior insula
- ウ. the bilateral anterior insula and dorsolateral prefrontal cortex, but not the anterior cingulate cortex
- エ. the bilateral anterior insula, dorsolateral prefrontal cortex, and anterior cingulate cortex
- 問3 In the passage, how many research studies are summarized?
- ア. one
- イ. two
- ウ. three
- エ. more than three
- 問4 In the Ultimatum Game, a player who behaves in a practical way could also be called .
- ア. irrational
- イ. selfish
- ウ. fair
- エ. moral
- 問5 The term "(1)evolved," as it is used in the passage, is closest in meaning to .
- ア. changed
- イ. followed
- ウ. created
- エ. lasted
- 問6 The term "(2)operate," as it is used in the passage, is closest in meaning to .
- ア. choose
- イ. feel
- ウ. want
- エ. behave
- 問7 The term "(3)observations," as it is used in the passage, is closest in meaning to .
- ア. operations
- イ. intake
- ウ. examinations
- エ. care
- 問8 The word "(4)they" refers to .
- ア. the researchers
- イ. the chimpanzees
- ウ. the patients
- エ. the parts of the brain
- 問9 The phrase "(5)for instance," as it is used in the passage, can best be replaced with .
- ア. at once
- イ. for example
- ウ. at least
- エ. for now
- 問10 Which word best replaces ( A ) in the passage?
- ア. Unfortunately
- イ. Second
- ウ. Therefore
- エ. Finally
- 問11 According to the underlined sentence (i), what does "the socially expected way" refer to?
- ア. rejecting unfair offers
- イ. accepting unfair offers
- ウ. rejecting fair offers
- エ. accepting fair offers
- 問12 Which of the following can be inferred from the passage?
- ア. Fairness developed after humans separated from chimpanzees.
- イ. Chimpanzees understand and accept the idea of unfairness.
- ウ. Humans feel comfortable if they receive an unfair offer.
- エ. If humans receive a brain injury, they will not be practical.
- 問13 What would be the best title for this passage?
- ア. Differences between Chimpanzees and Humans
- イ. The Brain: Accept It or Not
- ウ. Evolution of the Fair Mind
- エ. Finding Human's Ancestors