Group Psychology and the Analysis of the Ego by Sigmund Freud

We started from the fundamental fact that an individual in a group is subjected through its influence to what is often a profound alteration in his mental activity. His emotions become extraordinarily intensified, while his intellectual ability becomes markedly reduced, both processes being evidently in the direction of an approximation to the other individuals in the group; and this result can only be reached by the removal of those inhibitions upon his instincts which are peculiar to each individual, and by his resigning those expressions of his inclinations which are especially his own. We have heard that these often unwelcome consequences are to some extent at least prevented by a higher ‘organisation' of the group; but this does not contradict the fundamental fact of Group Psychology - the two theses as to the intensification of the emotions and the inhibition of the intellect in primitive groups.

Our interest is now directed to discovering the psychological explanation of this mental change which is experienced by the individual in a group.