MATURATION OF PRECEDENCE-EFFECT THRESHOLDS - FULL-TERM AND PRETERM INFANTS

The precedence effect (PE) occurs when a sound is played through two laterally placed loudspeakers with the sound from one loudspeaker preceding the other by a brief interval. This results in perceptual insensitivity to the location of the delayed sound. Three groups of infants and one group of adults were tested for their PE delay thresholds, that is, the delay at which the PE breaks down and two sounds are heard. The infants were full-term 7-month-olds, full-term 10-month-olds, and preterm infants of 7 months corrected age. In accord with previous findings, thresholds were found to decrease with increasing age. More importantly, thresholds decreased as a function of maturation from conception rather than as a function of experience since birth. The results are discussed in terms of cortical maturation, and implications for at-risk infants are outlined.