IRCCS C. Mondino Foundation, Pavia, Italy.
College of Education, Psychology, and Social Work, Flinders University, South Australia, Australia.
Laterality. 2021 Nov;26(6):706-724. doi: 10.1080/1357650X.2021.1920972. Epub 2021 Apr 27.
Healthy individuals typically show a leftward attentional bias in the allocation of spatial attention along the horizontal plane, a phenomenon known as pseudoneglect, which relies on a right hemispheric dominance for visuospatial processing. Also, healthy individuals tend to overestimate the upper hemispace when orienting attention along the vertical plane, a phenomenon that may depend on asymmetric ventral and dorsal visual streams activation. Previous research has demonstrated that when attentional resources are reduced due to increased cognitive load, pseudoneglect is attenuated (or even reversed), due to decreased right-hemispheric activations. Critically, whether and how the reduction of attentional resources under load modulates vertical spatial asymmetries has not been addressed before. We asked participants to perform a line bisection task both with and without the addition of a concurrent auditory working memory task with lines oriented either horizontally or vertically. Results showed that increasing cognitive load reduced the typical leftward/upward bias with no difference between orientations. Our data suggest that the degree of cognitive load affects spatial attention not only in the horizontal but also in the vertical plane. Lastly, the similar effect of load on horizontal and vertical judgements suggests these biases may be related to only partially independent mechanisms.
健康个体在水平面上分配空间注意力时通常表现出左注意偏向，这种现象被称为假性忽视，它依赖于右半球对视空间处理的优势。此外，健康个体在垂直面上定向注意力时往往会高估上半空间，这种现象可能依赖于不对称的腹侧和背侧视觉流的激活。先前的研究表明，当由于认知负荷增加而导致注意力资源减少时，由于右半球激活减少，假性忽视会减弱（甚至反转）。至关重要的是，在负荷下减少注意力资源是否以及如何调节垂直空间不对称性尚未得到解决。我们要求参与者在同时进行水平或垂直定向线条的听觉工作记忆任务的情况下执行线二分任务。结果表明，增加认知负荷会减少典型的左偏/上偏，而与定向无关。我们的数据表明，认知负荷的程度不仅会影响水平方向，也会影响垂直方向的空间注意力。最后，负荷对水平和垂直判断的相似影响表明，这些偏差可能与仅部分独立的机制有关。
