According to a much-reported survey carried out in 2002,
Britain then had 4.3 million closed-circuit television cameras (CCTV)--one for
every 14 people in the country. That figure has since been questioned, but few
doubt that Britons are closely observed when they walk in the streets. It is
supposed to prevent and detect crime. Even the government’s statistics, though,
suggest that the cameras have done little to reduce the worst sort of criminal
activity, violence. That may, however, be about to change, and
in an unexpected way. It is not that the cameras and their operators will become
any more effective. Rather, they have accidentally gathered a huge body of data
on how people behave, and particularly on how they behave in situations where
violence is in the air. This means that hypotheses(臆测) about violent behavior
which could not be tested experimentally for practical or ethical reasons, can
now be examined in a scientific way. And it is that which may help violence to
be controlled. One researcher who is interested in this approach
is Mark Levine, a social psychologist at Lancaster University in Britain who
studies crowds. Crowds have a bad press. They have been blamed for anti-social
behavior through mechanisms that include peer pressure and the diffusion (扩散)of
responsibility--the idea that "someone else will do something, so I don’t have
to". But Dr. Levine thinks that crowds can also diffuse potentially violent
situations and that crime would be much higher if it were not for crowds. As he
told a seminar called "Understanding Violence", which was organized in
Switzerland earlier this month, he has been using CCTV data to examine the
bystander effect, a so-called phenomenon whereby people who would help a
stranger in distress if they were alone, fail to do so in the presence of
others. His conclusion is that it isn’t so. In fact, he thinks, having a crowd
around often makes things better. Dr. Levine thinks crime happens more without crowds, which shows crowds have the function of ______.