Heart rate-defined phases of attention, look duration, and infant performance in the paired-comparison paradigm

Four-month-old infants (N = 68) were tested in a paired-comparison familiar ization-novelty recognition task in which the length of choice trials was s ystematically manipulated. Peak look duration during pretest and familiariz ation periods significantly predicted a dichotomous measure of recognition performance, but recognition was unaffected by choice-trial length. Heart r ate (HR) was simultaneously assessed during the task, and the amount of tim e infants spent in various HR-defined phases of attention was assessed. Lon ger durations of looking during pretest and familiarization were significan tly associated with more time spent in both sustained attention (SA) and at tention termination (AT). Of these two variables, only individual differenc es in AT accounted for significant variance in recognition memory performan ce. A final analysis addressed the possibility that individual differences in AT mediated the relation between look duration and recognition performan ce. These findings provide support for the hypothesis that individual diffe rences in the disengagement of attention underlie the relation between look duration and cognitive performance in early to midinfancy.