Nettelbeck T, Robson L, Walwyn T, Downing A, Jones N
Am J Ment Defic. 1986 Jul;91(1):78-91.
The effect of eye movements away from a target on accuracy of visual discrimination was examined. In Experiment I inspection time was measured for 10 mildly mentally retarded and 10 nonretarded adults under two conditions, with each trial initiated by the subject or under experimental control. Retarded subjects did not gain any advantage from controlling trial onset. Video records of eye movements revealed that retarded subjects glanced off-target more than did nonretarded controls, but this was not sufficient to explain appreciably slower inspection time of the retarded group. Experiment 2 supported this conclusion; the same subjects completed a letter-discrimination task with direction of gaze monitored automatically. Although retarded subjects' eye gaze was more scattered early during a trial, gaze was appropriately directed by the time that the target appeared. Results from both experiments supported the hypothesis that speed of central, perceptual processing is slower among retarded persons, over and above the influence of distractibility. Results from three experiments in Part II were consistent with this interpretation. Experiment 3 was designed to eradicate trials among retarded subjects in which gaze was not properly directed, but results showed that too few such events occurred to influence accuracy. Experiment 4 demonstrated that the preparatory procedure in the previous studies resulted in efficient eye gaze among retarded subjects. Experiment 5 confirmed that lower discriminative accuracy among 10 retarded adults (compared with 10 nonretarded controls) was not due to less-efficient orientation prior to discrimination.
研究了眼睛从目标移开对视觉辨别准确性的影响。在实验一中，对10名轻度智力迟钝的成年人和10名非智力迟钝的成年人在两种条件下测量了检查时间，每种试验由受试者启动或在实验控制下进行。智力迟钝的受试者没有从控制试验开始中获得任何优势。眼动视频记录显示，智力迟钝的受试者比非智力迟钝的对照组更多地偏离目标扫视，但这不足以明显解释智力迟钝组检查时间明显较慢的原因。实验2支持了这一结论；相同的受试者完成了一项字母辨别任务，注视方向由自动监测。虽然智力迟钝的受试者在试验早期的目光更分散，但在目标出现时目光得到了适当引导。两个实验的结果都支持了这样一个假设，即智力迟钝者的中枢感知处理速度较慢，这超出了分心的影响。第二部分三个实验的结果与这一解释一致。实验3旨在消除智力迟钝受试者中注视方向不正确的试验，但结果表明此类事件发生得太少，不足以影响准确性。实验4表明，先前研究中的准备程序导致智力迟钝受试者的目光有效。实验5证实，10名智力迟钝成年人（与10名非智力迟钝对照组相比）较低的辨别准确性并非由于辨别前的定向效率较低。
