It has been suggested that infants respond preferentially to infant-directed speech because their auditory sensitivity to sounds with extensive frequency modulation (FM) is better than their sensitivity to less modulated sounds. In this experiment, auditory thresholds for FM tones and for unmodulated, or pure, tones in a background of noise were…

Behavioral and electrophysiological evidence suggests a gradual, experience-dependent specialization of cortical face processing systems that takes place largely in the 1st year of life. To further investigate these findings, event-related potentials (ERPs) were collected from typically developing 9-month-old infants presented with pictures of…