The present study is aimed at developing a training program that enables students to repeat writing exercises by focusing on the production of rationales and to examine whether “rationale production training”improves their
reasoning skills. Two groups totaling 158 first-year high school students participated in this study.
The result showed significant training effects on the number of rationales produced for arguments and as well as perspectives from which to consider rationales,suggesting that rationale production training was effective for Japanese high school students for them to think through topics from a broad perspective. In addition, that meta-cognitive awareness to “thinking”of themselves,such as“viewpoints relied upon in producing rationales”,could be encouraged through rationale production training.