Nettelbeck T, Hirons A, Wilson C
Am J Ment Defic. 1984 Jul;89(1):91-8.
Performance of mentally retarded and nonretarded adults on simple visual discrimination tasks was compared. Experiment 1 involved a lines-discrimination task used in previous research to measure inspection time. A dichoptic stimulus presentation procedure was employed, with target and masking stimuli presented to different eyes so that only central masking could occur. Experiment 2 involved a discrimination between two lights in different positions, demonstrating that masking was characterized by constant stimulus-onset-asynchrony, because the relationship between target duration and the interval between target offset and mask onset was additive. Results from both experiments confirmed that for both retarded and nonretarded subjects, the backward masking procedures used interfered with visual processing at a central level. In Experiment 3 markedly deviant smooth pursuit eye movements in a pendulum tracking task occurred among retarded subjects but not among nonretarded subjects. This deviancy was additional to other indications of poor attention. In the retarded group the correlation between estimates of inspection time and deviant eye tracking was .64, but other instances of inattentiveness were not related to either of these two measures. This finding was interpreted in terms of an involuntary dysfunction within some central attentional system that involves at least three qualitatively different levels.
比较了智障和非智障成年人在简单视觉辨别任务中的表现。实验1采用了先前研究中用于测量检查时间的线条辨别任务。采用了双眼分视刺激呈现程序，将目标刺激和掩蔽刺激呈现给不同的眼睛，以便只发生中央掩蔽。实验2涉及对不同位置的两盏灯进行辨别，结果表明掩蔽的特征是刺激起始异步恒定，因为目标持续时间与目标消失和掩蔽开始之间的间隔关系是相加的。两个实验的结果均证实，对于智障和非智障受试者而言，所采用的逆向掩蔽程序在中央水平上干扰了视觉处理。在实验3中，智障受试者在钟摆跟踪任务中出现了明显异常的平稳跟踪眼球运动，而非智障受试者则未出现。这种异常是注意力不集中的其他表现之外的情况。在智障组中，检查时间估计值与异常眼球跟踪之间的相关性为0.64，但其他注意力不集中的情况与这两种测量方法均无关联。这一发现被解释为涉及至少三个质的不同水平的某些中央注意力系统内的非自愿功能障碍。
