Predicting others’ intention involves motor resonance: EMGevidence from 6- and 9-month-old infants

The study explores infants’ ability to generate on-line predictions about others’ action goalsthrough the recruitment of motor resonance mechanisms. To this aim, electromyographywas recorded from mouth-opening suprahyoid muscles (SM) of 9-month-old infants whilewatching a video of an adult agent reaching-to-grasp an object and bringing it either tomouth or head. The results demonstrated, for the first time, that at the age of 9 monthsthere is a dynamic mirror modulation of SM activity by action observation, with the infant’smuscles responsible for the action final goal being recruited from the action outset. Thecomparison with the responses of 6-month-olds tested on the same task showed that inyounger and older infants there is a different chronometry of the SM activation with respectto the different phases of the observed action (i.e., bringing vs. grasping, respectively).Results suggest that motor resonance mechanisms triggered within the infants’ motorsystem by action observation undergo gradual development during the first year of life.They also indicate that motor resonance may reflect anticipation of the agent’s intentionbased on the goal of the action.