La inmensa obra de Jean Piaget estuvo siempre dirigida por intereses epistemologicos, tratando de descubrir como se produce el conocimiento, mientras que Bc1"el Inhelder, su mas estrecha colaboradora desde los anos treinta, se ha interesado mas bien por estudiar al sujeto psicologico real. En los anos setenta, Inhelder inicio un vasto programa de investigacion destinado a descubrir los procedimientos que siguen los ninos en la resolucion de tareas, frente al estudio de las estructuras que hacen posible la conducta. Este enfoque venia a converger con la corriente de la psicologia norteamericana conocida como psicologia cognitiva. No se trata, entonces, de estudiar los grandes progresos que hace el sujeto para organizar el mundo, sino los pequenos avances que realiza cuando se enfrenta con una tarea concreta para resolverla. Desde esa epoca, Inhelder, con un variado equipo de colaboradores, ha realizado numerosas investigaciones y ha ido perfilando una posicion psicologica propia, un nuevo funcionalismo. Esta obra no solo recoge las investigaciones empiricas, sino tambien el enfoque general, y discute numerosos problemas muy debatidos en la psicologia actual, estableciendo un dialogo continuo con la psicologia cognitiva, con el procesamiento de la informacion y con la simulacion del comportamiento. Las aportaciones de Cellerier contribuyen a la discusion de los grandes problemas que tiene planteada la teoria psicologica.
Bärbel Elisabeth Inhelder was a Swiss psychologist most known for her work under psychologist and epistemologist Jean Piaget and their contributions toward child development. Born in St. Gallen, Switzerland, Inhelder initially showed interest in education. While attending high school she became interested in Sigmund Freud's writing and information on adolescents. She then moved to Geneva where she studied at the University of Geneva Institut Jean-Jacques Rousseau earning her bachelor's and doctoral degrees both in psychology. Inhelder continued her work at the University of Geneva up until her retirement. During her time at Geneva, she worked alongside Jean Piaget collaborating on experimental work targeted toward child development. Their collaboration began with her dissertation on children's conservation and continued for 50 years. Inhelder's work was significant in the discovery of the formal operational stage of child development occurring during the transition between childhood and adolescence. Inhelder and Piaget were joint on many publications of their research. Inhelder's contributions to developmental psychology resulted in her being elected as a Foreign Honorary Member of the American Academy of Arts and Sciences. Bärbel Inhelder died in 1997 of natural causes and her work is still used in developmental psychology today.