The same mode of approach was also employed by Freud in his book Group Psychology and the Analysis of the Ego (1921), where he argued that 'crowd psychology, and with it all social psychology, is parasitic on individual psychology'.
Model pendekatan yang sama juga digunakan oleh Freud dalam bukunya, Group Psychology and the Analysis of the Ego (1921), di mana ia berpendapat bahwa “psikologi kerumunan, dan oleh karena itu psikologi sosial, adalah parasit bagi psikologi individu.