Developmental trends in mother-infant interaction from 4-months to 42-months: using an observation technique.

BACKGROUND: It is clear that early social interaction follows from mother-infant interaction after pregnancy. Many researchers have illuminated this interaction in the first years of life. Most common mother-infant interaction is the attachment behavior of an infant. The Japan Children's Study (JCS) development psychology group hypothesis is that the early mother-infant interaction will predict later social behaviors. But the method applied to evaluate this interaction mainly comes from the evaluation of the whole observation situation and is dependent upon the coder. We applied a new observational method that checked the on/off status of behavior and recorded sequentially. METHODS: Using a semi-structured observation setting as our method, we analyzed the developmental change of mother-infant interaction within a toy situation. RESULTS: The result indicated that mother-infant interaction with a toy altered at around 9-months and is salient to the usual developmental change of joint attention. Additionally cluster analysis suggested that the developmental pattern is divided into two clusters. This is the first report on a developmental pattern of joint attention. CONCLUSIONS: These results indicated that the developmental trend of gaze direction and vocalization is one candidate of measure for evaluating the mother infant social interaction from the point of joint attention.

Infant responses to maternal still-face at 4 and 9 months.

This study investigated developmental changes in infant responses to maternal still-face (SF) situations. Infants (21 males and 25 females) of Japanese mothers were observed in a face-to-face SF paradigm, comprising four phases (normal/SF/normal/SF), at two infant ages (4 and 9 months). The infants' facial expression, gaze direction, and vocalization were coded in both SF and normal interaction conditions. The results indicated that infants at both ages showed a decrease in displaying positive facial expression and gazing at their mothers during SF conditions. The 4-month-old displayed emotional expression and directed their gaze toward their mothers more frequently than the 9-month-old. However, the 9-month-old vocalized more often in SF situations, attempting to elicit responses from their mothers. The "carry-over" effect was observed only in 9-month-old. The results were discussed in the context of developmental changes in infants' social skills to cope with an emotionally stressful situation.