标题:126-129 幼児の精神的発達に関する実験的研究(その1)(4.発達(3),日本教育心理学会第5回総会部門別研究発表要旨・討論の概要) [in Japanese] 126-129 An experimental study on mental development of young children (I)(4.Development (3),PROCEEDINGS OF THE FIFTH ANNUAL CONVENTION OF JAPANESE ASSOCIATION OF EDUCATIONAL PSYCHOLOGY PAPERS AND THE SUMMARIES OF DISCUSSIONS) [in Japanese]