母子相互作用場面における表情の同調・調律と子どもの分離不安反応型 : 4ヶ月齢と9ヶ月齢の比較  [in Japanese] The relationships between the reaction patterns of separation anxiety among infants and the synchronization/ attunement of facial expression during the mother-infant interaction : A comparative study between 4-month and 9-month olds  [in Japanese]