Swiss psychologist and educator.
Bärbel Inhelder is permanently linked to Jean Piaget as a remarkable instance of scientific collaboration. Inhelder started working with Piaget in the early 1930s; by the 1940s, as she recalled, Piaget told her he needed her "to counter his tendency toward becoming a totally abstract thinker." Piaget never lost sight of his epistemological goals, while Inhelder was much more of a psychologist.
Inhelder was born in 1913 in the German-speaking Swiss city of St. Gall, the only child of cultured parents. In 1932, she moved to Geneva to study at Edouard Claparède's Rosseau Institute. At Piaget's suggestion, she examined children's comprehension of conservation of quantities. The book they published together on the subject in 1941 was the first of many other collaborations. In her dissertation, using conservation tests as diagnostic tools, Inhelder confirmed Piaget's claim that the sequence of developmental stages is invariant, and showed how mentally retarded children were fixated at a certain stage. In exemplary Piagetian fashion, she did not focus on test results alone, but on how subjects arrived at their answers; this allowed her to determine their general cognitive skills as well. In 1943, after finishing her dissertation, Inhelder settled in Geneva for good; she became a professor at Geneva University in 1948, and retired in 1983. She died in 1997.
In the 1950s, after investigating children's conceptions of geometry and probability with Piaget, Inhelder devised a series of clever situations to study the development of inductive reasoning. In one of them, subjects were asked to discover the factors (length, thickness, and so forth) that make metal rods more or less flexible. This work led to the definition of the developmental stage of "formal operations," characterized by the capacity for hypothetico-deductive thinking. This study resulted in two influential books, The Growth of Logical Thinking from Childhood to Adolescence (1958) and The Early Growth of Logic in the Child (1969). In both, Inhelder conducted the psychological research, while Piaget elaborated logical models for describing mental structures. Inhelder's later work with Piaget and others dealt with mental imagery and memory (both shown to depend on the subject's developmental level), the effects of training on cognitive development, and the impact of malnutrition on early intellectual development. Since the 1970s, Inhelder analyzed problem-solving behavior in children and adolescents, with the goal of understanding their strategies and implicit theories.
Inhelder was the first to use Piagetian tests as a diagnostic tool; today, most test batteries include Piagetian items. She also created several of the most widely replicated experiments of developmental research. By the nature of her thinking, which was more focused than Piaget's on the specifically psychological processes of cognitive development, as well as by her close personal contacts with American researches, Inhelder played a crucial role in turning the Piagetian approach into a mainstream paradigm of cognitive developmental psychology.
Inhelder, B. "Autobiography," in G. Lindzey, ed. A History of Psychology in Autobiography, vol. 8. Stanford: Stanford University Press, 1989.
——. The Diagnosis of Reasoning in the Mentally Retarded . Trans. W. B. Stephens et al. New York: J. Day, 1968.