A set of tasks theoretically presumed to require equivalent logical competence (multiplication of classes, multiplication of relations, seriation, and transitivity) was administered to 64 first and second graders. Response measures emphasizing the operative and figurative aspects were compared within each task. (Author/SDH)

Nine tasks were designed to test the developmental sequence of three types of "because" (affective, physical, concrete logical) in 100 children aged 3 to 7 years. The tasks tested whether comprehension of "because" preceded its usage and at what point children understood that sentences with reversed clauses were incorrect.…

Children in grades 1, 3, and 5 and college students were given a variety of judgment tasks contrasting the comparison of quantity with the comparison of proportions to determine whether the understanding of proportions develops before formal operations. Results indicated that the comprehension of abstract relations requires formal operations.…