Mother–infant co-regulation in dyadic and triadic contexts at 4 and 6 months of age

This study examined interpersonal co-regulation in 80 mother–infant dyads when interacting face-to-face and with an object, at the infant ages of 4 and 6 months. We found that co-regulation patterns differed between conditions and with development. Under the dyadic condition, the dyads were mostly unilateral, with only the mother attending to the infant's focus, while in the triadic context, they were mostly symmetrical, with both mother and infant mutually engaged. While confirming previous studies showing that interpersonal co-ordination is a relatively rare event in face-to-face exchanges, this result shows that the contrary is instead true when objects are available. Also, unilateral co-regulation significantly increased in the triadic context from 4 to 6 months, together with an increase in the active role of the infant during symmetrical exchanges. The development of manipulative skills that occurred during this age period might have promoted these co-regulation changes, through improvement of the infant activities with objects, both independently and with the mother. Finally, involvement in triadic interactions appears to relate to temperamental aspects, being favoured by the infant's disposition to be soothed by the caregiver. Overall, our results support the view of early social development as a context-based and multidimensional process. Highlights: Investigation of how mothers and infants co-regulate in face-to-face interactions and with toys in the first 6 months of life. Eighty mother–infant dyads are observed longitudinally in dyadic and triadic interactions at 4 and 6 months of age. Social-mediated object exchanges favour symmetrical co-regulation in early mother–infant interactions, whereas unilateral co-regulation prevails in face-to-face contexts.