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. There are, on the other hand, individuals whose apparent low suggestibility is of the highest social value. There are striking instances, throughout the long struggle toward human liberty, of persons who could withstand the public opinion of their own day in the light of some ideal which they cherished, of men who needed no other approval than their consciences, their better selves, or their god. Socrates drinking the fatal hemlock, Christ upon the cross, the Christian saints, Joan of Arc, the extreme dissenters of every generation, are instances of men and women seemingly unmoved by the praise and blame of their contemporaries. Sustained by their deep inner conviction of the justice and significance of their mission, they have been content to suffer scorn, ridicule, and martyrdom at the hands of their own generation in a persistent devotion to what in their eyes constituted the highest good of mankind.