The development and temporal dynamics of spatial orienting in infants.

Shifts of visual attention can be studied in adults by cueing a particular spatial location and assessing the speed of detection of targets presented in the cued location as compared to other locations. A number of studies have used spatial cueing paradigms in an attempt to study attention shifts in infants. However, these studies have employed different procedures, time courses, measures, and age groups, making comparison between them difficult. The present experiments were designed to investigate the effects of varying the cue-target time interval on the speed and direction of orienting in 2-, 4-, and 6-month-old infants. The results of Experiment 1 indicated that, while 2-month-old infants showed only weak effects of the cue, 4-month-old infants show facilitation to a cued location when a target appears 200 ms after cue onset, and inhibition of responses to the same location when the target appears 700 ms after the cue onset. Six-month-old infants showed evidence of inhibition, but not facilitation. One account of this pattern of data is that 6-month-olds shift attention faster than do 4-month-olds. This hypothesis was tested in Experiment 2 in which four different cue-target intervals were used with a group of 7-month-old infants. The results obtained were consistent with the hypothesis that infants get faster to shift attention to a spatial location with age.