Fast responses to neglected targets in visual search reflect pre-attentive processes: an exploration of response times in visual neglect
Fast responses to neglected targets in visual search reflect pre-attentive processes: an exploration of response times in visual neglect
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DOI：
10.1016/s0028-3932(01)00230-5
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发表时间：
2002-01-01
期刊：
影响因子：
2.6
通讯作者：
Espeseth, T
中科院分区：
文献类型：
--
作者：
Laeng, B;Brennen, T;Espeseth, T
AE是一名右半球卒中导致视觉忽视症状的患者。在第一个实验中，AE忽略了一个单一的视觉目标，该目标在一半的试验中出现，并出现在计算机屏幕上的可变和不可预测的位置。目标与屏幕背面的对比度也是不同的。AE表现出对左侧目标的严重忽视，但他对错误报告为缺席的目标的RT比正确拒绝甚至右侧命中更快。AE快速“忽视”反应似乎表明目标被检测到，但他仍然没有意识到它的存在。与直觉相反的是，随着目标的可分辨性降低，他的快速命中速度也会越来越快。对被忽视的目标的快速反应反映了猜测策略的可能性，与目标存在的不确定性程度成比例地使用，进行了研究。AE快速失误确实更快的刺激的对比度较低的水平，但他的错误率并不倾向于接近猜测模型预测的机会水平。在第二个实验中。AE搜索字母Z，出现在一半的试验中，在变量集的干扰字母。在一种情况下，干扰物都是O型的，因此与目标物有一个基本特征不同。在另一种情况下，干扰物是各种字母，这些字母与目标字母的特征组合不同。关键发现是，对被忽视目标的快速反应仅发生在简单特征搜索任务中，而不是复杂特征（结合）任务中。我们解释这些研究结果表明，AE前注意处理可以检测到弹出目标的左手边，但注意搜索是错误的，并提前中止。因此，当“弹出”形式存在时，患者的注意力系统具有“早期启动”，但也可能无法“抓住”检测到的目标：因此，通过不注意刺激，患者仍然不知道其存在，并将快速响应“不”当前目标。(C)2002爱思唯尔科技有限公司版权所有。
AE is a patient who suffered a right hemisphere stroke resulting in Visual neglect symptoms. In the first experiment, AE neglected a single visual target that was present in half of the trials and appeared in variable and Unpredictable positions on the computer screen. The contrast of the target to the screen's back-round was also varied. AE demonstrated severe neglect for left-sided targets, and yet his RTs to targets reported incorrectly as absent were faster than correct rejections and even right-sided hits. AEs fast "neglect" responses seem to indicate that the target was detected but that he remained unaware of its presence. Counter intuitively, his fast misses got faster as the discriminability of the target decreased. The possibility that fast responses to neglected targets reflected a guessing strategy, used proportionally to the degree of uncertainty of a target presence, was examined. AEs fast misses were indeed faster at lower level of contrast of the stimulus, but his error rate did not tend to approach the chance level as the guessing model would predict. In a second experiment. AE searched for the letter Z, present on half of the trials, among variable sets of distractor letters. In one condition the distractors were all O's and therefore differed from the target by an elementary feature. In the other condition, the distractors were various letters that differed from the target by combinations of features. The key finding was that fast responses to neglected targets occurred only in the simple feature search task and not in the complex features (conjunction) task. We interpret these findings as indicating that AEs pre-attentive processing can detect pop-up targets on the left-hand side, but that the attentional search is faulty and is aborted early. Hence, the patient's attentional system has an "early start" when "pop-out" forms are present, but can also fail to "grab" the detected target: consequently, by not attending to a stimulus, the patient remains unaware of its presence and will quickly respond "no" to present targets. (C) 2002 Elsevier Science Ltd. All rights reserved.