The effectiveness of praise and blame in determining action depends also on the explicitness with which they are expressed. In contemporary life the control of public opinion is made precarious because there is so rarely complete or palpable unanimity on any subject among the variety of groups that constitute a modern society. In a large city there are so many groups, so many sets of opinion, that an individual may not feel any great pressure of praise and blame except from the small circle of people with whom he is associated. In small communities action is restrained by the fear of ostracism or contempt of the whole group among whom one is living. But in large cities, where one may not be known by one's next-door neighbor, this restraint is much reduced. The temptations of a metropolis, so often referred to in the lurid literature of the day, consist not in temptations more numerous than or different from those in smaller places, but in the marked absence of social control as compared with small villages where every one knows everyone else's business.
The influence of the social estimate on individual conduct depends finally on individual differences in suggestibility. In normal individuals susceptibility to the praise and blame of others is very high, especially among the close circle of friends, professional and business associates among whom one moves. This susceptibility is heightened when the praise or blame comes from persons superior in social status, though here the element of fear of the consequences of displeasing is perhaps more important than the responsiveness to the praise and blame itself. To the praise and blame of close associates most men are also highly suggestible, not less so when there is equality in social status. "Birds of a feather flock together," but humans tend to _become_ similar _because_ they flock together. There are few men who can withstand the pressure of doing what their group approves, and refraining from doing what it disapproves.
In some men susceptibility to the attitudes of others is extremely low, and of such are both criminals and martyrs made. In the prisons of this country there are a large number of men absolutely indifferent to the usual social standards, completely undeterred by the codes of conduct by which other people cannot help but be governed. Such absolute callousness to the feelings which govern the majority of mankind as we read of every now and then in the trial of some desperate criminal, is not infrequently associated with abnormally low intelligence, the sodden stolidity of the traditional criminal type. Where it appears, as it sometimes does, in criminals of high intelligence, it is regarded by psychiatrists as a specific abnormality, comparable to color-blindness or a physical deformity.