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Everyday, familiar materials and formal materials were used to test the Piagetian classification and formal operational abilities of highly educated adults of both sexes. 30 subjects were in their 30s, and 30 were of retirement age. These adult subjects did not show mastery of the tasks, and the materials used influenced scores. Results were discussed from the point of view of a new model of adult lifespan development related to formal operational activities in adults and related to the experience-structure dialectic in mature adult thought.
Jan D. Sinnott (Fri,) studied this question.