Visual Masking
Visual Masking
复制标题
视觉掩蔽
作者：
G. Mowbray;L. Durr
视觉掩蔽，有时被称为运动对比，是一种与另一种相似刺激的近距离封闭相关的刺激的效果变化。病毒掩蔽的表现通常有两种形式。要么被掩盖的刺激和被掩盖的刺激是小的、均匀的光场，要么是常见的几何图形，如圆盘和环面。在前一种情况下，研究了空间相邻的刺激！·•，以及空间上的一致性2，而效果的测量是根据目标的外观阈值的变化1•2或根据目标的表观亮度的变化，作为刺激的时间连续性的函数”。在后一种情况下，应用了一些不同的考虑，因为目标通常是白色背景上的黑色圆盘，而掩蔽刺激是与圆盘同心的黑色环•-•。在这些调查中，掩蔽的通常措施是未能报告在圆盘和环之间的某些时间间隔上对圆盘的感知。在这两种情况下，可以显示出向后和正向掩蔽的发生，即掩蔽刺激可以在目标之后或之前，并且可以测量到效果。对阈值效应和亮度区分的研究提供了由于掩蔽而降低视觉灵敏度的信息，而环和盘的研究则没有。他们关注的主要是控制形成的时间方面及其意义。报告目标磁盘的出现或消失是非常主观的。更客观表征的刺激如何受到掩蔽的影响这一问题很少受到关注。这次交流是试图纠正这种情况，并处理掩蔽研究的一个有争议的方面；也就是说，掩蔽效应是纯粹的视网膜掩蔽效应，还是有一些更核心的方面。在即将报道的两个实验中，目标刺激是从150个单词中随机抽取的一个常见的四个字母的英语单词。屏蔽的
VISUAL masking, sometimes called motacontrast, is a change in the efficacy of a stimulus associated with close occlll'rence in time of another but similar stimulus. Demonstrations of vi1mal masking have generally taken one of two forms. Either the masked and the masking stimuli have been small, homogeneous fields of lightl-3, or else they have been common geometrical figures such as a disk and an annulus'-8• In the former case stimuli have been investigated which were spatially adjacent!·•, as well as spatially coincident2 and the measure of the effect has been in terms of a change of threshold of appearance of the target1• 2 or in terms of a change in apparent, brightness of the target as a function of the temporal contiguity of the stimuli". In the latter case, somewhat different considerations apply in that the target has most frequently been a black disk on a white background, while the masking stimulus has been a black ring concentric with the disk•-•. The usual measure of masking in these investigations has been the failure to report perception of the disk at some temporal separation between disk and ring. In the two cases, both backward and forward masking can be shown to occur, that i8 the masking stimulus can either follow or precede the target and an effect can be measured. The investigations on threshold effects and brightness discrimination provide information on reduction of visual sensitivity due to masking, whereas the ring and disk studies do not. Their concern has been mainly with the temporal aspects of contolll'formation, and their mea. slll'ement the highly subjective one of reporting the appearan<'e or the disappearance of a target disk. The problem of how more objectively denoted stimuli are affected by masking has received little attention. This communication is an attempt to remedy that situation and to deal with one controversial aspect of masking studies in general; namely, whether the masking effect is a. purely retinal one or whether it has some more central aspects•·•·•. In the two experiments to be reported, the target stimulus was a common four-letter English word drawn at random from a pool of 150 words. The masking