Development of arousal-modulated visual preferences in early infancy.

Abstract

Looking preferences to visual temporal frequencies between 1 and 8 Hz were studied longitudinally at 3 ages (newborn, 1 month, 4 months; N = 77) in 3 conditions: less aroused (after feeding), more aroused-internal (before feeding), and more aroused-external (after feeding with 8 Hz visual stimulation before each trial). Replicating and extending previous results, a strong interaction between arousal level and stimulus frequency was found at newborn and 1 month. Infants preferred faster stimuli when less aroused and slower stimuli when more aroused, with no differences between the 2 more aroused conditions even though produced by different operations. At 4 months, the interaction with arousal no longer existed; faster stimuli were preferred in all conditions. Thus, after the transition in visual behavior normally occurring at 2-3 months, arousal no longer played a major role, possibly as a result of emergent cortical sensory-specific attention. Differentiation within and between the processes influencing levels of arousal and attention appears to occur during early infancy. To investigate transitions in these processes, the present study extends previous findings of arousal-modulated attention in newborn infants to infants at 1 and 4 months of age. For neonates, arousal and attention work interdependently as a single, quantitatively organized self-limiting homeostatic system that combines the effects of internal and external factors to specify systematic directional shifts in attention to particular stimuli (see Gardner & Karmel, 1983; Karmel, Gardner, & Magnano, 1991; Turkewitz, Gardner, & Lewkowicz, 1984; Turkewitz, Lewkowicz, & Gardner, 1983). This basic characterization of arousal-modulated attention is evidenced by similar systematic shifts in visual preferences toward less stimulating events (e.g., slower temporal frequencies or less contour in spatial patterns) when neonates are both endogenously more aroused (unswaddled before