Honesty is the best policy，as the English saying goes.Unfortunately，honesty often leaves us when no one is watching，British psychologists reported last week.
Researchers at UK's Newcastle University set up an experiment in their psychology department's coffee room.
They set a kettle，with tea，coffee and milk on the counter and hung up a sign listing the price for drinks.People helping themselves to a cup of tea were supposed to put a few cents in the box nearby.
The scientists hung a poster above the money box，and changed each week between pictures of gazing(注视的)eyes and pictures of flowers.The researchers found that staff paid 2.76 times more for their drinks when the image of the eyes was hung.
“We were shocked by the size of the effect，”said Gilbert Roberts，one of the researchers.
Eyes are known to be a powerful perceptual(知觉的)signal for humans，scientists say.
“Even though the eyes were not real，they still seemed to make people behave more honestly，”said Melissa Bateson，a behavioral biologist and leader of the study.
Researchers believe the effect throws light on our evolutionary past.It may arise from behavioral characteristics that developed when early humans formed social groups to strengthen their chances of survival.For social groups to work，individuals had to cooperate，rather than act selfishly.“There's an argument that if nobody is watching us，it is in our interests to behave selfishly.But when we're being watched we should behave better.So people see us as cooperative and behave the same way towards us，”Bateson said.
The new finding indicates that people have a striking response to eyes.That might be because eyes and faces send a strong biological signal we have evolved to respond to，Bateson said.
The finding could be put to practical use.For example，images of eyes could ensure ticket sales on public transport and improve surveillance(监视)systems to deter antisocial(反社会)behavior.
1．The story is written mainly to ________.
A．warn you to behave honestly whether you are alone or not
B．explain the root of cheating in exams with no teachers present
C．describe how the experiment in Newcastle University worked
D．inform us of a strong reaction that people have to eyes
2．The experiment carried out in Newcastle University made researchers
think that ________.
A．honesty is not the best policy
B．evolution has a big influence on our behavior
C．humans have to form social groups to survive
D．people are more relaxed when not being watched
3．From the text，we know that ________.
A．no one acts selfishly when being watched
B．the function of eyes is not only biological but social
C．the image of eyes worked as well as the picture of flowers
D．a waiter was there serving people drinks in the experiment
4．The word “deter” underlined in the last paragraph could be replaced by
________.
A．prevent B．discover
C．watch D．research