The paper examines the heuristic value of the concept of psychological regression. The language of semiotic mediation of behavioral acts and mental operations seems to be more adeguate at the present stage of research than the traditional psychoanalytic methaphors of mental "economy" and cathexis. This position is supported by a number of developmental and clinical studies undertaken by L. S. Vygotsky and his students. Analysis of these studies allows to make a tentative suggestion regarding a formal scale of cognitive advancement/ regression, which may replace the search for empirical coincidences in the behavior of children, people in "primitive" societies, and mental patients. While constructing such a scale one should take into account the type of communicative situation in which "regressive" forms of behavior of thinking are observed.