The extent to which mothers and their infants can synchronize their activity levels and cycles of engagement and disengagement has been seen as fundamental to healthy affective development in the infant. Ten mothers and their infants were studied to consider the possibility of a neurophysiological base to synchronization potential. The infants' neurophysiological capacities were examined within two to three days of birth using the Brazelton Neonatal Behavioural Assessment Scale. The same infants and their mothers were assessed in their interactions after three months. The mothers' physiological responses to stimulation also were examined. Significant correlations were found between neonatal responsivity to stimuli and motor maturity, maternal stimulus screening capacity and the nature of the mother‐infant interaction at three months. In particular, infants who were more socially responsive and attentive to stimuli had mothers with a greater capacity for ‘screening out’ redundant stimuli. Moreover, these same dyads spent more time in social engagement and had fewer cycles of disengagement. These findings, together with other studies, suggest that particular neurophysiological capacities of mothers and infants may be more conducive to the synchronization of their interactions than others. This raises the possibility that the chaotic asynchrony observed in clinically diagnosed mother‐infant disturbances may have a neurophysiologic