Cerebral processing of mother's voice compared to unfamiliar voice in 4-month-old infants

In order to investigate the neurophysiological mechanisms related to the infant's preference of maternal stimuli over other stimuli, auditory event-related potentials (ERPs) were recorded in responses to the mother's voice and to a voice of an unfamiliar female in 15 infants at the age of 4 months. Stimuli were presented in intermittent and alternating trains of four identical stimuli (mother's voice or an unfamiliar voice). A significant amplitude difference was observed in the responses. This was seen as a negative ‘shift’ in the responses to mother's voice after approximately 350 ms. The finding suggests that the infants allocate more attention to process their own mothers’ voices compared to unfamiliar voices and it may work in favor of establishing and strengthening an emotional tie between the infant and its mother.