The relation between audition and vision in the human newborn.

Four studies were conducted to investigate the relation between audition and vision in the human newborn. In all four studies visual activity was recorded with infrared corneal-reflection technqiues in 1- to 4-day-old infants. Study 1 concerned the effects of sound at midline on scanning in darkness and in a lit but formless field. In the dark compared to light, newborns maintained better eye control, centralized fixations, scanned with smaller eye movements, scanned less dispersely, and were wider-eyed. In a blank field, sound caused newborns to maintain better eye control, centralize fixations, scan with small eye movements, constrain fixations, and be wider-eyed than in silence. Sound had little effect on scanning in the dark beyond constraining fixations. Study 2 concerned the effects of sound at midline on scanning vertical and horizontal edges. Visual activity was different for the two visual stimuli. While viewing a vertical rather than a horizontal edge, newborns maintained better eye control and fixated closer to the position of the vertical edge. Newborns crossed the position of the horizontal edge when that edge was present. Sound affected scanning in general, centralizing fixations for newborns not already looking centrally, but sound did not affect the frequency of edge crossing. Study 3 concerned the effects of laterally presented sound on scanning spatially consonant or dissonant vertical bars. The major finding was that infants were sensitive to the spatial property of sound. Infants shifted fixations first toward and then gradually away from sound. Study 4 was an attempt to determine whether there is an effort constraint on the simultaneous functioning of auditory and visual systems. The effects of two differentially salient sounds on scanning two differentially salient visual stimuli were examined. Although the results appeared to support the idea of an effort constraint, the data were accounted for parsimoniously in terms of the spatial influence of sound of scanning. The data on visual activity were discussed in terms of the presence of inherent information-acquisition routines in the newborn. It was concluded that sound influences visual epistemic behavior even at birth.