Predictive tracking over occlusions by 4-month-old infants
Predictive tracking over occlusions by 4-month-old infants
复制标题
DOI：
10.1111/j.1467-7687.2007.00604.x
复制
发表时间：
2007-09-01
影响因子：
3.7
通讯作者：
Rosander, Kerstin
中科院分区：
文献类型：
--
作者：
von Hofsten, Claes;Kochukhova, Olga;Rosander, Kerstin
两项实验研究了16-20周大的婴儿如何在视觉上追踪一个在水平轨迹上振荡的物体，并将其放置在中央。为了确定婴儿在物体到达之前倾向于将目光转移到出侧的原理，我们操纵了遮挡宽度、振荡频率和运动幅度，使遮挡持续时间在0.20到1.66秒之间。通过这些操作，我们能够区分封口处“预测”行为背后的几种可能的行为模式。测试了四种这样的模式。首先，如果时间的流逝决定了扫视发生的时间，那么将目光转移到咬合物上的趋势预计是消失后时间的函数。其次，如果现有遮挡物边缘的视觉显著性决定了扫视发生的时间，那么遮挡物宽度将决定再现前的凝视转移，而不是振荡频率、幅度或速度。第三，如果对前一次遮挡持续时间的记忆决定了被试何时将目光转移到遮挡物上，那么无论遮挡持续时间是否改变，预计在下一次遮挡时，目光都会在相同的潜伏期后转移。最后，如果婴儿的再现前凝视转移是基于他们表征物体运动的能力（认知模式），那么可以预期，凝视转移在咬合者上的延迟时间与遮挡持续时间成比例。眼睛和头部的运动以及物体的运动以240赫兹的频率进行测量。在49%的段落中，婴儿在物体到达封堵器的另一侧之前将目光转移到了那里。这种目光转移的趋势无法用消失后时间的流逝来解释。也不能完全用遮挡期间存在的视觉信息（即遮挡宽度）来解释。相反，我们发现再现前凝视转移的延迟是由物体再现的时间决定的，它是三个因素共同作用的函数。结果表明，物体的速度在遮挡过程中被表征出来，婴儿在他们的“心眼”中追踪遮挡器后面的物体。
Two experiments investigated how 16-20-week-old infants visually tracked an object that oscillated on a horizontal trajectory with a centrally placed occluder. To determine the principles underlying infants' tendency to shift gaze to the exiting side before the object arrives, occluder width, oscillation frequency, and motion amplitude were manipulated resulting in occlusion durations between 0.20 and 1.66 s. Through these manipulations, we were able to distinguish between several possible modes of behavior underlying 'predictive' actions at occluders. Four such modes were tested. First, if passage-of-time determines when saccades are made, the tendency to shift gaze over the occluder is expected to be a function of time since disappearance. Second, if visual salience of the exiting occluder edge determines when saccades are made, occluder width would determine the pre-reappearance gaze shifts but not oscillation frequency, amplitude, or velocity. Third, if memory of the duration of the previous occlusion determines when the subjects shift gaze over the occluder, it is expected that the gaze will shift after the same latency at the next occlusion irrespective of whether occlusion duration is changed or not. Finally, if infants base their pre-reapperance gaze shifts on their ability to represent object motion (cognitive mode), it is expected that the latency of the gaze shifts over the occluder is scaled to occlusion duration. Eye and head movements as well as object motion were measured at 240 Hz. In 49% of the passages, the infants shifted gaze to the opposite side of the occluder before the object arrived there. The tendency to make such gaze shifts could not be explained by the passage of time since disappearance. Neither could it be fully explained in terms of visual information present during occlusion, i.e. occluder width. On the contrary, it was found that the latency of the pre-reappearance gaze shifts was determined by the time of object reappearance and that it was a function of all three factors manipulated. The results suggest that object velocity is represented during occlusion and that infants track the object behind the occluder in their 'mind's eye'.