SummaryProfessor Wallon stresses here the difficulties which have entangled the Study of personality in European countries, because of the subjective and idealistic line of thought which was suggested by philosophers like Descartes, Taine, Bergson, and more recently the existentialists. Their method results in cutting off the solidarity which really exists between the organic and the psychic sides of personality, as also between personality itself and the environment.He then applies these remarks to the special case of emotional behavior, the analysis of (...) which has cost him so much time and work. Contrary to other modes of behavior, which consist in overt movements and aim at modifying the physical world, emotion is an expressive and subject‐moulding process, whereby reacting to à given situation the individual provokes among social partners similar or complementary attitudes.This interaction between the Self and the social milieu, is one of the chief factors which govern the progressive construction of personality. Through alternating identification and opposition, it takes à dialectical character, and shows the essential complementarity of the subject and the environment, contrary to the substantialistic and scholastic view of the past, which, reifying separately these non‐autonomous entities, tried then vainly to reconcile and reunite them.It should be pointed out that, according to Dr Wallon, emotion corresponds to one of the four levels of behavior which progressively appear in the growing child, and form in the adult à hierarchical organisation:1. Impulsive behavior: reflex and automatic actions.2. Emotional behavior.3. Sensori‐motor behavior.4. Projective behavior.More details on these four stages can be found in tome VIII of Encyclopidie francaise, La vie mentale, composed under Dr Wallon's supervision. (shrink)