The relationship between gaze shifts elicited during observed and performed actions in infants and adults

We asked whether other people’s actions are understood by projecting them onto one’s own action programs and whether this mode of control is functioning in infants? Adults’ and infants’ gaze and hand movements were measured in two live situations. The task was either to move an object between two places in the visual field, or to observe the corresponding action performed by another person. When performing the action, infants and adults behaved strikingly similar. They initiated the hand and gaze movements simultaneously and gaze arrived at the goal ahead of the hand. When observing such actions, the initiation of the gaze shifts was delayed relative to the observed movement in both infants and adults but gaze still arrived at the goal ahead of the hand. The infants’ gaze shifts, however, were more delayed at the start, less proactive at the goal, and showed kinematic variability indicating that this mode of functioning is somewhat unstable in 10-month-old infants. In summary, the results showed that both adults and infants perceive the goal of the action and move gaze there ahead of time, but they did not support the idea of a strict matching of the kinematics between the eye movements carried out when performing and observing actions.