Distributed and focused attention: Neuropsychological evidence for separate attentional mechanisms when counting and estimating
Distributed and focused attention: Neuropsychological evidence for separate attentional mechanisms when counting and estimating
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DOI：
10.1037/0096-1523.33.5.1076
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发表时间：
2007-10-01
影响因子：
2.1
通讯作者：
Humphreys, Glyn W.
中科院分区：
文献类型：
--
作者：
Demeyere, Nele;Humphreys, Glyn W.
证据提出了两种模式的注意力运作的失认症。作者研究了视觉计数的病人，GK，谁有严重的障碍，在连续扫描整个场景，是无法计算的项目在视觉显示的数量。然而，GK判断2个显示器的相对大小的能力始终高于机会，即使整体亮度不随存在的项目数量而变化。此外，几个变量对GK的计数和震级估计有不同的影响。通过使用更容易分组的元素和以规则配置呈现元素，促进了震级估计，但不计数。相比之下，通过将元素放置在不同的颜色中来促进计数，而幅度估计被破坏。此外，GK的表现对幅度估计任务被打断，要求他计数的元素存在。这些数据表明，GK可以在集中或分散注意模式下处理视觉刺激。当处于集中注意力模式时，由于视觉空间的外显表征受损，注意力的串行扫描较差，从而限制了性能。
Evidence is presented for 2 modes of attention operating in simultanagnosia. The authors examined visual enumeration in a patient, GK, who has severe impairments in serially scanning across a scene and is unable to count the numbers of items in visual displays. However, GK's ability to judge the relative magnitude of 2 displays was consistently above chance, even when overall luminosity did not vary with the number of items present. In addition, several variables had a differential impact on GK's counting and magnitude estimation. Magnitude estimation but not counting was facilitated by using elements that grouped more easily and by presenting the elements in regular configurations. In contrast, counting was facilitated by placing the elements in different colors while magnitude estimation was disrupted. Also GK's performance on magnitude estimation tasks was disrupted by asking him to count the elements present. The data suggest that GK can process visual stimuli in either a focused or distributed attention mode. When in a focused attention mode, performance is limited by poor serial scanning of attention due to an impaired explicit representation of visual space.