Now that the principle of the interindividual diffusion of feeling has been stated and explained, we may return to our main line of research and examine its bearings on the expressional impulse. We have seen that in the social surroundings of the individual there is enacted a process resembling that which takes place within his own organism. Just as functional modifications spread from organ to organ, just as wider and wider zones of the system are brought into participation in the primary enhancement or inhibition, so a feeling is diffused from an individual to a circle of sympathisers who repeat its expressional movements. And just as all the widened “somatic resonances” contribute to the primary feeling-tone increased strength and increased definiteness, so must the emotional state of an individual be enhanced by retroactive stimulation from the expressions by which the state has, so to say, been continued in others. By the reciprocal action of primary movements and borrowed movements, which mutually imitate each other, the social expression operates in the same way as the individual expression. And we are entitled to consider it as a secondary result of the general expressional impulse, that when mastered by an overpowering feeling we seek enhancement or relief by retroaction from sympathisers, who reproduce and in their expression represent the mental state by which we are dominated. In point of fact we can observe in the manifestations of all strong feelings which have not found a satisfactory relief in individual expression, a pursuit of social resonance. A happy man wants to see glad faces around him, in order that from their expression he may derive further nourishment and increase for his own feeling. Hence the benevolent attitude of mind which as a rule accompanies all strong and pure joy. Hence also the widespread tendency to express joy by gifts or hospitality. In moods of depression we similarly desire a response to our feeling from our surroundings. In the depth of despair we may long for a universal cataclysm to extend, as it were, our own pain. As joy naturally makes men good, so pain often makes them hard and cruel. That this is not always the case is a result of the increased power of sympathy which we gain by every experienced pain. Moreover, we have need of sympathetic rapport for our motor reactions against pain. All the active manifestations of sorrow, despair, or anger which are not wholly painful in themselves are facilitated by the reciprocal influence of collective excitement. Thus all strong feelings, whether pleasurable or painful, act as socialising factors.[120] This socialising action may be observed at all stages of development. Even the animals seek their fellows in order to stimulate themselves and each other by the common expression of an overpowering feeling. As has been remarked by Espinas, the flocking together of the male birds during the pairing season is perhaps as much due to this craving for