Wattam-Bell J
University of Cambridge, Department of Experimental Psychology, England.
Vision Res. 1994 Apr;34(7):877-83. doi: 10.1016/0042-6989(94)90038-8.
The sensitivity of 3-month-old infants to direction of motion in random-dot patterns was assessed by measuring coherence thresholds for the discrimination of a pattern, in which opposite directions were segregated into alternate horizontal strips, from an unsegregated pattern. The coherently moving dots had a displacement size of 0.16 deg (velocity 8 deg/sec), and their direction of motion reversed periodically. For both infants and an adult subject coherence thresholds decreased with increasing height of the segregated strips, and with increasing duration of the interval between direction reversals. However the infants required larger minimum heights and longer minimum durations in order to extract motion direction. Even under the best conditions infants were markedly less sensitive, with coherence thresholds of around 50%, compared with 5-7% for the adult. In addition, within the group of infants coherence thresholds were negatively correlated with age. This developmental increase in motion sensitivity at an intermediate velocity suggests that a large part of the improvement in upper and lower velocity thresholds during development is a result of a uniform increase in sensitivity across all velocities, though the results do not rule out additional specific improvements in sensitivity at the extremes of the velocity range.
通过测量辨别一种图案（其中相反方向被分隔成交替的水平条带）与未分隔图案之间的相干阈值，评估了3个月大婴儿对随机点图案中运动方向的敏感度。相干运动的点位移大小为0.16度（速度为8度/秒），且其运动方向周期性反转。对于婴儿和一名成年受试者而言，相干阈值均随着分隔条带高度的增加以及方向反转之间间隔时间的延长而降低。然而，婴儿需要更大的最小高度和更长的最短持续时间才能提取运动方向。即使在最佳条件下，婴儿的敏感度也明显较低，相干阈值约为50%，而成年人则为5 - 7%。此外，在婴儿组中，相干阈值与年龄呈负相关。这种中等速度下运动敏感度的发育性增加表明，发育过程中上下速度阈值的大部分改善是所有速度敏感度均匀增加的结果，尽管结果并不排除在速度范围极端情况下敏感度有额外的特定改善。
