Heart rate and behavioral measures of attention in six-, nine-, and twelve-month-old infants during object exploration.

In this study we examined the effect of heart rate and behavioral measures of attention on distractibility of 6-, 9-, and 12-month-old infants. The infants were presented with a toy, and a distractor was presented while they attended to the toy. The distractor was presented during heart rate changes indicating sustained attention or attention termination, or during periods of time when behavioral ratings indicated the infant was in focused or casual attention. There were longer distraction latencies during attentional engagement as defined by heart rate changes or behavioral ratings than for periods of inattention. Infants had the longest distraction latencies when heart rate and behavior measures were congruent with respect to attention engagement (heart rate deceleration and focused attention). Conversely, latencies were shortest for congruent values of inattention (heart rate acceleration and casual attention). Infant information processing may be greatest when a heart rate deceleration occurs simultaneously with an episode of focused attention.