Department of Psychology, University of Iowa Iowa City, IA, USA.
Front Psychol. 2013 Aug 15;4:533. doi: 10.3389/fpsyg.2013.00533. eCollection 2013.
Because items near our hands are often more important than items far from our hands, the brain processes visual items near our hands differently than items far from our hands. Multiple experiments have attributed this processing difference to spatial attention, but the exact mechanism behind how spatial attention near our hands changes is still under investigation. The current experiments sought to differentiate between two of the proposed mechanisms: a prioritization of the space near the hands and a prolonged disengagement of spatial attention near the hands. To differentiate between these two accounts, we used the additional singleton paradigm in which observers searched for a shape singleton among homogenously shaped distractors. On half the trials, one of the distractors was a different color. Both the prioritization and disengagement accounts predict differently colored distractors near the hands will slow target responses more than differently colored distractors far from the hands, but the prioritization account also predicts faster responses to targets near the hands than far from the hands. The disengagement account does not make this prediction, because attention does not need to be disengaged when the target appears near the hand. We found support for the disengagement account: Salient distractors near the hands slowed responses more than those far from the hands, yet observers did not respond faster to targets near the hands.
因为我们手上的物品通常比远离手的物品更重要，所以大脑对手上附近的视觉物品的处理方式与远离手的物品不同。多项实验将这种处理差异归因于空间注意力，但关于手附近的空间注意力如何变化的具体机制仍在研究中。目前的实验旨在区分两种被提议的机制：对手附近空间的优先级和对手附近空间注意力的延长脱离。为了区分这两种解释，我们使用了额外的单一范例，在该范例中，观察者在同质形状的干扰物中搜索形状单一。在一半的试验中，一个干扰物是不同的颜色。优先级和脱离注意力的解释都预测，手附近的不同颜色的干扰物会比远离手的不同颜色的干扰物对手的反应速度更慢，但优先级解释还预测，手附近的目标比远离手的目标的反应速度更快。脱离注意力的解释没有做出这个预测，因为当目标出现在手附近时，注意力不需要脱离。我们发现支持脱离注意力的解释：手附近的显著干扰物比远离手的干扰物更能减缓反应，但观察者对手附近的目标的反应速度并没有更快。
