Fortenbaugh Francesca C, Robertson Lynn C, Esterman Michael
GRECC & Research Services, Department of Veterans Affairs, Boston Healthcare System, MA, USA; Department of Psychiatry, Harvard Medical School, MA, USA.
Department of Psychology, University of California, Berkeley, CA, USA.
Vision Res. 2017 Feb;131:26-36. doi: 10.1016/j.visres.2016.12.002. Epub 2016 Dec 30.
Visual spatial attention is a critical process that allows for the selection and enhanced processing of relevant objects and locations. While studies have shown attentional modulations of perceived location and the representation of distance information across multiple objects, there remains disagreement regarding what influence spatial attention has on the underlying structure of visual space. The present study utilized a method of magnitude estimation in which participants must judge the location of briefly presented targets within the boundaries of their individual visual fields in the absence of any other objects or boundaries. Spatial uncertainty of target locations was used to assess perceived locations across distributed and focused attention conditions without the use of external stimuli, such as visual cues. Across two experiments we tested locations along the cardinal and 45° oblique axes. We demonstrate that focusing attention within a region of space can expand the perceived size of visual space; even in cases where doing so makes performance less accurate. Moreover, the results of the present studies show that when fixation is actively maintained, focusing attention along a visual axis leads to an asymmetrical stretching of visual space that is predominantly focused across the central half of the visual field, consistent with an expansive gradient along the focus of voluntary attention. These results demonstrate that focusing sustained attention peripherally during active fixation leads to an asymmetrical expansion of visual space within the central visual field.
视觉空间注意力是一个关键过程，它允许对相关物体和位置进行选择并增强其处理。虽然研究已经表明在多个物体上注意力对感知位置和距离信息表征的调制作用，但对于空间注意力对视觉空间的底层结构有何种影响仍存在分歧。本研究采用了一种大小估计方法，即参与者必须在没有任何其他物体或边界的情况下，判断在其各自视野范围内短暂呈现的目标的位置。目标位置的空间不确定性被用来评估在不使用外部刺激（如视觉线索）的情况下，分布式和集中注意力条件下的感知位置。在两个实验中，我们测试了沿基本轴和45°斜轴的位置。我们证明，在空间区域内集中注意力可以扩大视觉空间的感知大小；即使这样做会使表现的准确性降低。此外，本研究结果表明，当主动保持注视时，沿视觉轴集中注意力会导致视觉空间的不对称拉伸，这种拉伸主要集中在视野的中央半部，这与沿自愿注意力焦点的扩展梯度一致。这些结果表明，在主动注视期间在周边持续集中注意力会导致中央视野内视觉空间的不对称扩展。
