Being unable to study here every category of jury, I shall only examine the most important—that of the juries of the Court of Assize. These juries afford an excellent example of the heterogeneous crowd that is not anonymous. We shall find them display suggestibility and but slight capacity for reasoning, while they are open to the influence of the leaders of crowds, and they are guided in the main by unconscious sentiments. In the course of this investigation we shall have occasion to observe some interesting examples of the errors that may be made by persons not versed in the psychology of crowds.
Juries, in the first place, furnish us a good example of the slight importance of the mental level of the different elements composing a crowd, so far as the decisions it comes to are concerned. We have seen that when a deliberative assembly is called upon to give its opinion on a question of a character not entirely technical, intelligence stands for