Dr. McDougall recognizes, as do most modern psychologists, the great social importance of this "current" of which Lecky speaks; he terms it mass-suggestion. "Children," he says, "largely in virtue of their suggestibility, rapidly absorb the knowledge, beliefs, and especially the sentiments of their social environment. But most adults also remain suggestible, especially towards mass-suggestion, and towards the propositions which they know to be supported by the whole weight of society, or by long tradition."[79] This also he calls prestige suggestion. Individual suggestibility, he considers, is conditioned by native disposition and character, and dependent upon the relative strengths of the two instincts of self-assertion and subjection. He does not, however, appear to assign to this factor of suggestion any conspicuous part in the excitation of such emotions as, for instance, anger, moral indignation, shame and remorse. But the simultaneous excitation of the same emotion in crowds is attributed to the action of the gregarious instinct which is accountable for the sympathetic induction of emotion. The explanation given of the fact that the instinctive behaviour of one animal directly excites similar behaviour on the part of his fellows, consists in the assumption that among gregarious animals each of the principal instincts has a special perceptual inlet that is adapted to receive the sense-impressions made by the expressions of the same instinct in other animals of the same species: thus, for example, the fear instinct, _inter alia_, has a special perceptual inlet that renders it excitable by the sound of the cry of fear; the instinct of pugnacity is similarly excited through a perceptual inlet by the sound of the roar of anger, and so on. Whatever the value of this assumption it is clear that the emotional excitement of an aggregation of individuals reacts with cumulative intensity upon each member of it. It is sufficient, however, to say that there exists in the human species a fundamental impulse of gregarious attraction, analogous in the physical world to the law of gravitation, which tends to produce aggregations of men and to intensify their suggestibility in relation to sheer weight of numbers and proximity. If we accept the view that the subjective mind is liable to be directly influenced by other subjective minds with which it is _en rapport_, the hypothesis of special perceptual inlets, designed for each instinct to receive only the corresponding sense-impressions derived from the efferent action of the same instinct in other individuals, becomes of secondary importance. Any cause which simultaneously provokes emotional excitement in a large body of people tends to bring them into _rapport_, thence onwards a community of feeling has been established, like elements coalesce, foreign elements are dissipated or repulsed, the mass will think, feel and act as a collective whole, the impulse or emotion of one will