A total of 82 fourth and fifth graders participated in a 15-week intervention program during which they confronted problems requiring formal operational thought. Subjects showed advancement toward formal operations on the pendulum and chemicals problems (Inhelder and Piaget) and on a third problem on immediate and 4-month posttests. (Author/JH)

Study concerned with the mechanisms in terms of which the developmental transformation from one cognitive structure to another occurs. (Author)

Responds that questions of study by Kuhn and others (PS 524 345) in this issue were motivated by concerns about the role of scientific thinking in general thinking, not in development of scientific reasoning. Study was meant to increase understanding of role of strategies in development, not provide definitive explanation of how strategies fit…

Used a microgenetic method to examine knowledge acquisition as a process by coordinating existing theories with new evidence. Subjects were 17 community college students (ages 22-47) and 15 fourth graders. Assessed knowledge acquisition in problem solving in both physical and social domains. Found multiple strategies for, and varying levels of,…

The development of children's comprehension of cause and effect relationships was studied in 68 kindergarten, first grade, and second grade children. (BRT)

Presentation of a "natural experiment" problem situation to fourth, sixth, and eighth graders and college students revealed that not until adolescence could subjects isolate alternative or additive causes in a multivariable situation. (JMB)