2～4歳児における語想起能力の発達に関する横断的検討―事物名称命名能力およびカテゴリー分類能力との関連

A cross-sectional study into the development and interconnection of word recall ability, object naming and categorization abilities in two-to-four- year-old children

　本研究では，語義における細部の違いを音声言語で言及可能となる基礎的能力と考えられる語想起能力について，幼児を対象にカテゴリー分類能力と事物名称命名能力とともに横断的に検討した．研究方法として，2歳0か月～4歳11か月までの健常幼児64名を対象に，語想起課題およびカテゴリー分類課題，事物名称命名課題の3課題を実施し，6か月ごとの生活年齢で6群に分けて，これらの遂行の可否と正答率を比較した．その結果，語想起課題の正答語の平均は3歳6か月以降，年齢が上がるにつれて増加した．3課題の遂行人数は3歳6か月以降差がみられないものの，3歳6か月～3歳11か月間において語想起課題の可否ごとに2課題をみると，語想起可能なグループは語想起不可能なグループに比べ2課題ともに平均得点が高かった．これらの結果について，各能力の関連性と課題の内容，実施順序から考察を加えた．

　We performed a cross-sectional study on word fluency, which is considered a basic ability for referring to fine differences in word meaning in spoken language.　We also assessed category classification ability and object naming ability.　The subjects were 64 healthy children aged from 2 years 0 months to 4 years 11 months.　Each child performed three tasks (word fluency, category classification, and object naming).　The children were classified into 6 groups by chronological age at 6-month intervals.　The groups were compared in terms of the number of children who could accomplish all three tasks and the correct answer rate.　The mean number of correct answers in the word fluency task increased with age in groups older than 3 years 6 months;however, the number of subjects who passed all three tasks did not change in groups older than 3 years 6 months.　When the results of the category classification and object naming tasks were examined in the 3 years 6 months to 3 years 11 months group, the mean number of correct answers was higher for both tasks in the subgroup of children who passed the word fluency task than in the subgroup who did not.　These results are discussed in terms of the task contents, task order, and the relationship among the three abilities.