Morgan M J, Ward R M, Castet E
Department of Visual Science, Institute of Ophthalmology, London, UK.
Q J Exp Psychol A. 1998 May;51(2):347-70. doi: 10.1080/713755766.
We report that spatial cueing of a parafoveal target in the presence of distractors enhances orientational acuity for that target. When no distractors were present, orientation thresholds were in the range 1-4 degrees. For long exposure times, distractors increased threshold by the amount predicted from a winner-takes-all spatial uncertainty model. For short (100-msec) exposures followed by a random dot mask, the rise in threshold with distractors was considerably greater than that predicted from spatial uncertainty. For brief exposures the effect of distractors was greater when the target and distractors were spatially crowded rather than widely spaced. Adding a tilt to the distractors in the opposite direction to the target increased thresholds still further. Cueing the target with a spatial pointer decreased the effect of distractors, even when they were crowded. We suggest that when attention cannot be appropriately focused, discrimination is carried out by a relatively coarse texture analyser, which averages over several elements, and that focused attention permits the analysis of the target over a smaller area of space.
我们报告称，在存在干扰物的情况下对中央凹旁目标进行空间线索提示可提高该目标的定向敏锐度。当不存在干扰物时，定向阈值在1 - 4度范围内。对于较长的曝光时间，干扰物会使阈值增加到赢家通吃空间不确定性模型预测的幅度。对于短时间（100毫秒）曝光后接随机点掩蔽的情况，干扰物导致的阈值上升远大于空间不确定性模型预测的幅度。对于短暂曝光，当目标和干扰物在空间上拥挤而非间隔较大时，干扰物的影响更大。给干扰物添加与目标相反方向的倾斜会进一步提高阈值。用空间指针提示目标可降低干扰物的影响，即使它们是拥挤的。我们认为，当注意力无法适当集中时，辨别是由相对粗糙的纹理分析器进行的，该分析器对几个元素进行平均，而集中注意力则允许在较小的空间区域内对目标进行分析。
