As a field of study, group dynamics has roots in both psychology and sociology. Wilhelm Wundt (1832–1920), credited as the founder of experimental psychology, had a particular interest in the psychology of communities, which he believed possessed phenomena (human language, customs, and religion) that could not be described through a study of the individual. On the sociological side, Émile Durkheim (1858–1917), who was influenced by Wundt, also recognized collective phenomena, such as public knowledge. Other key theorists include Gustave Le Bon (1841–1931) who believed that crowds possessed a 'racial unconscious' with primitive, aggressive, and antisocial instincts, and William McDougall (psychologist), who believed in a 'group mind,' which had a distinct existence born from the interaction of individuals. (The concept of a collective consciousness is not essential to group dynamics.)