|Budget Amount *help
¥1,500,000 (Direct Cost : ¥1,500,000)
Fiscal Year 1993 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1992 : ¥1,000,000 (Direct Cost : ¥1,000,000)
In this study, developmental processes of disjunctive logical reasoning were investigated. Two reasoning tasks concering disjunctive sentence, that is, a disjunctive four-card-problem in the first year of this research project and a disjunctive syllogism task in the second year, were administered to the second, fourth, sixth and eighth granders, 20 students in each grade.
The results of both tasks showed that most of the lower graders were unable to access these tasks and even the sixth or eighth graders had much difficulty in reasoning logically. As predictedat the first stage of this project, disjunctive logical reasoning skills were acquired in preadolescence, namely, at the stage of formal operations, and not in childhood. Based on these results, it was concluded that disjunctive logical reasoning is not a precocial reasoning schema as indicated by Braine & Rumain (1981), but one of late-acquired formal operations as predicted by Inhelder & Piaget (1955).