French psychologist, sociologist and criminologist, one of the founders of social psychology. Tarde put forward the concept that the basis of social ties of an individual is three factors: imitation, invention and opposition (opposition to innovation). Among these factors, imitation is dominant as the basis for the individual’s assimilation of the attitudes, beliefs, and feelings of other people. The concept of imitation is considered to be the source for the socio-psychological theory of mass psychology (see Mass Psychology in Chapter 1.8. Key Psychological Terms in Social Psychology).