Researchers believe the effect sheds light on our evolutionary past. It may arise from behavioral features that developed when early humans formed social groups to strengthen their chances of survival. For social groups to work, individuals had to co-operate, 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 co-operative 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. The finding could be put to practical use, too. For example, images of eyes could increase ticket sales on public transport and improve supervision systems to prevent antisocial behavior.

46．The experiment conducted in Newcastle University shows that        .

A．people enjoy free drinks more than paid ones

B．most people are dishonest if nobody is watching

C．people like pictures of flowers more than pictures of eyes

D．people are more honest when watched by pictures of eyes

47．Gilbert Roberts was shocked because        .

A．so many people had participated in the experiment

B．so many of the participants were dishonest

C．the effects of the pictures of flowers and gazing eyes were so different

D．the effects of eyes and other perceptual signals were so powerful

48．The phrase “sheds light on” in Paragraph 4 probably means “       ”.

A．hints at                  B．makes clearer         C．points to                D．further proves

49．According to the passage, early humans        .

A．were less selfish than the present-day people

B．were more co-operative in nature

C．had to be co-operative to survive

D．had to behave better than the present-day people

50．Images of eyes could be put up in the following places EXCEPT        .

A．subway entrances   B．supermarkets          C．back streets            D．hotel bedrooms