某实验小组设计了如图(a)所示的实验装置，通过改变重物的质量，利用计算机可得滑块

Research shows that humans switch from selfish to unselfish behavior when they are watched. Do you?
A picture of a set of eyes on a computer screen can cause a change in the way people act. Even images of eyes on a charity donation, collection box encourage people to be unselfish, because people put more money in a
collection box that has a picture of eyes on it than they do when a flower symbol is on the box.
Manfred Milinski from the Max-Planck Institute for Evolutionary Biology in Germany and Bettina Rockenbach of the University of Berlin, the authors of a new study, found that people act better when they are being watched because they feel they will be rewarded for good behavior. Their report also referred to other research showing that this response of behaving well when watched is somehow coded into humans and people respond this way unconsciously, or without realizing it.
It is not just humans that act unselfishly when they are being watched. A fish called the grooming fish cleans other fish. When other fish are around, it is gentler. When no other fish are around, however, the grooming fish bites chunks from the fish it is supposed to be cleaning.
The researchers suggest that the best way to get people to behave in the correct way is to make them feel watched. This could be the reason for the success of a famous American army poster. On it was a picture of an elderly man staring fiercely and pointing, it appeared, to the person who was looking at the poster. Under the picture was the caption 'I Want You' It encouraged hundreds of thousands of young American men to join the army during the Second World War to fight the Germans and Japanese.
小题1:.
According to the report, why does a person behave better when he feels he is being watched?
   

A．He does not want to be shamed by others.

B．He needs to show he is a good person.

C．He desires others to like him more.

D．He feels he will receive some social reward.

小题2:.
．What is the text mainly about?

A．It describes changed behavior when observed.

B．It details ways to control people's behavior.

C．It tells how to make people work harder.

D．It discusses different advertising methods.

小题3:.
According to the text, which of the following statements is true?

A．People pretend to behave better when they are watched.
B．Fish bite other fish in a fish tank when they are alone.	C．People donate more money when they feel they are watched.
D．Soldiers fought better during World War II because of a poster.

小题4:.
．Where would the study described in the text most likely be found?

A．In a newspaper.	B．In a scientific journal.
C．In an advertising magazine.	D．In a science textbook.