Transitivism is at the same time the mode of confusion between the self and the other that the child undergoes between three and four years of age, and the transition phase which is characteristic of this stage of psychological maturation. The difficulties encountered by adolescent sportsmen (table tennis players) testify to the reappearance of the phenomenon of transitivism in adolescence.
The author shows how this disturbance is significant of the psychological elaborations of « puberty » confronted with the specular image. The ego ideal, which regulates the identification with the other, is the instance that allows for the passage from the duel with oneself to the competition with the other.