Teller D Y, Palmer J
Department of Psychology, University of Washington, Seattle 98195, USA.
Vision Res. 1996 Apr;36(7):955-74. doi: 10.1016/0042-6989(95)00170-0.
Four-week-olds, 9-week-olds, and adult subjects were tested with low spatial frequency sinusoidal gratings moving at a speed of 25 deg/sec. Luminance-modulated and red/green gratings were presented either separately, or superimposed and moving in opposite directions in a chromatic motion nulling paradigm. An adult observer judged the direction of the slow phase of the subject's eye movements. Luminance-modulated gratings elicited directionally appropriate eye movements in all three age groups, with contrast thresholds decreasing markedly with age. For red/green gratings alone, 4-week-olds responded only marginally, but 9-week-olds and adults produced consistent directionally appropriate eye movements. In the motion nulling condition, 15% contrast luminance-modulated gratings were about equally effective in nulling the motion of the red/green gratings in all three age groups. A formal model of the motion nulling paradigm, separating threshold and equivalent luminance contrast parameters, was developed and applied to the data. Model fits showed that equivalent luminance contrast was constant or nearly constant across age groups. This outcome is consistent with the hypothesis that, with respect to adults, infants show a uniform rather than a differential loss of sensitivity to moving red/green vs luminance-modulated stimuli.
对4周龄、9周龄和成年受试者进行测试，使用空间频率较低的正弦光栅，其移动速度为25度/秒。亮度调制光栅和红/绿光栅分别呈现，或者在彩色运动抵消范式中叠加并沿相反方向移动。一名成年观察者判断受试者眼球运动慢相的方向。亮度调制光栅在所有三个年龄组中都引发了方向合适的眼球运动，对比度阈值随年龄显著降低。仅对于红/绿光栅，4周龄的婴儿反应微弱，但9周龄的婴儿和成年人产生了一致的方向合适的眼球运动。在运动抵消条件下，15%对比度的亮度调制光栅在所有三个年龄组中对抵消红/绿光栅的运动效果大致相同。开发了一个运动抵消范式的形式模型，将阈值和等效亮度对比度参数分开，并将其应用于数据。模型拟合表明，等效亮度对比度在各年龄组中是恒定的或几乎恒定的。这一结果与以下假设一致：相对于成年人，婴儿对移动的红/绿刺激与亮度调制刺激的敏感度损失是一致的，而非有差异的。
