FIGURE 4.

Illustration of group means with standard deviation bars of N2 peak latencies for forward optic flow, reversed optic flow, and random visual motion for infants receiving extrastimulation, infants in the control group, and preterm infants at both testing sessions. In the first testing session, none of the infant groups were able to significantly discriminate between the three forms of visual motion, but extrastimulated infants showed significantly shorter latencies for forward (p < .05) and reversed optic flow (p < .05) compared with random visual motion. In addition, both extrastimulated and preterm infants had significantly shorter overall latencies than the control group (p < .05). From the first to the second testing, extrastimulated infants and control infants significantly improved their latencies, while preterm infants did not show any improvement in latency. In the second session, only extrastimulated infants and control infants were able to differentiate between the three forms of visual motion with the shortest latencies for forward optic flow, followed by reversed optic flow, and the longest latencies for random visual motion. Overall mean latencies were significantly shorter for extrastimulated infants compared with both control (p < .001) and preterm infants (p < .001) in the second session, indicating faster processing of visual motion for extrastimulated infants. Unlike extrastimulated and control infants, preterm infants did not decrease their latencies for visual motion during the course of the first year, and they did not show any evidence of being able to differentiate between forward and reversed optic flow, and random visual motion. ***p < .001, *p < .05