 Thus, Wallon articulated at the core of a dialectical model of concepts such as emotion, attitudes, and interpersonal bonds.His conception of the stages implied the idea that regression was possible, contrary to Piaget's model.Émile Jalley showed how Henri Wallon was an attentive reader of the German scientific and philosophical literature and how he contributed to the introduction and diffusion of certain concepts of Hegel and Freud into French psychological theory.