Objective: The authors examined whether changes in vagal tone were related to infant visual attention during auditory and visual events paired (synchronous) and not paired (asynchronous) in time. They predicted that infants would demonstrate greater visual attention to the synchronous slideshow and that vagal tone would decrease with visual attention.
Method: Nineteen infants, 3.5 months old, watched computer-generated synchronous or asynchronous slideshows of auditory and visual stimuli. Visual behavior and vagal tone data were collected. Vagal tone reflects physiological responses during attention or exposure to mild stressors. Repeated-measures analysis of variance examined differences in vagal tone across conditions.
Results: Visual behavior did not differ between the synchronous and asynchronous slideshow conditions. Vagal tone was significantly lower during the asynchronous slideshow.
Conclusion: Infants may discriminate synchronous from asynchronous stimuli without changing visual behavior. Implications related to play with toys or objects are discussed.