Infant sensorimotor decoupling from 4 to 9 months of age: Individual differences and contingencies with maternal actions

Triadic interactions, wherein infants coordinate attention between caregivers and objects of shared focus, are believed to facilitate infant learning, and emerge around 9-12 months of age (Carpenter et al., 1998). Sensorimotor decoupling, wherein infants look at one percept while manipulating another, or use each hand for different actions, was hypothesized (de Barbaro et al., 2016) to contribute to triadic skills by allowing infants to smoothly shift attention between objects and social partners. We explored the development of Hand-Hand (H-H) and Gaze-Hand (G-H) decoupling in 38 infants at 4, 6, and 9 months. We also tested contingencies between maternal behaviors and infant decoupling: i.e., whether decoupling events followed maternal object-directed actions. Both overall and contingent infant decoupling increased from 4 to 9 months. Decoupling rates (both G-H and H-H) predicted variance in infants' fine and gross motor scores. Contingent G-H decoupling at 6 months predicted BSID-III communication scores at 18 months. Thus the development of infant sensorimotor skills, including decoupling, allows infants to smoothly shift attention and participate in triadic interactions.