Abstract

The purpose of this study was to examine the effect of the familiarity of the premises on deductive reasoning with children. The subjects were 36 children in each age group, 5-year-old, 7-year-old, and 9-yeat-old. The reasoning task composed of 12 deductive syllogisms that were classified as three categories: real fact, equivocal fact and unreal fact. Twelve deductive syllogisms were presented randomly to each subject. The results of this study showed that the reasoning ability increased with age. That is, there were significant differences between all the comparisons among the premises in 5 and 7-year-old children while significant difference was not found between real fact and equivocal fact in 9-year-old children. It was also found that 5-yeat-old children showed relatively high performance on deductive reasoning with real facts. These results were interpreted as that 5-year-old children could reason deductively when the task was familiar with children, and deductive reasoning with real facts rapidly develops between 5 and 7-year-olds and deductive reasoning with equivocal facts rapidly develops between 7 and 9-year-old.