Visual Alertness in Neonates: Individual Differences and Their Correlates

Abstract

In a study of individual differences in neonates, frequencies and durations of spontaneous visual alertness were recorded and visual pursuit was measured in 32 2- to 3-day-old healthy neonates. Rank correlations of .60, .65, and .74 between the three visual measures suggested that infants who alerted frequently tended also to be the infants who alerted longest and who were most capable of visual pursuit. The results showed not only this intra-individual stability in the visual behaviors but also high variance between infants in their capacity for visual alertness. The infants' sex, parity, birthweight, estimated conceptual age, and postnatal age were not significantly related to the capacity for visual alertness, nor were the moderate levels of obstetric sedation used in this sample. The three visual measures, while tapping a shared capacity, had different correlates. Frequencies and durations of visual alertness were significantly related to a number of variables which had in common, moderate degrees of underlying activation and arousal. These factors did not contribute to visual pursuit. Sensitivity to auditory stimuli was significantly correlated with the capacity for visual pursuit but was unrelated to other visual measures.