Irwin David E, Robinson Maria M
Department of Psychology, University of Illinois Champaign, IL, USA.
Front Syst Neurosci. 2015 Nov 27;9:161. doi: 10.3389/fnsys.2015.00161. eCollection 2015.
Retinal image displacements caused by saccadic eye movements are generally unnoticed. Recent theories have proposed that perceptual stability across saccades depends on a local evaluation process centered on the saccade target object rather than on remapping and evaluating the positions of all objects in a display. In three experiments, we examined whether objects other than the saccade target also influence perceptual stability by measuring displacement detection thresholds across saccades for saccade targets and a variable number of non-saccade objects. We found that the positions of multiple objects are maintained across saccades, but with variable precision, with the saccade target object having priority in the perception of displacement, most likely because it is the focus of attention before the saccade and resides near the fovea after the saccade. The perception of displacement of objects that are not the saccade target is affected by acuity limitations, attentional limitations, and limitations on memory capacity. Unlike previous studies that have found that a postsaccadic blank improves the detection of displacement direction across saccades, we found that postsaccadic blanking hurt the detection of displacement per se by increasing false alarms. Overall, our results are consistent with the hypothesis that visual working memory underlies the perception of stability across saccades.
由眼球快速跳动引起的视网膜图像位移通常不易被察觉。最近的理论提出，扫视过程中的感知稳定性取决于以扫视目标物体为中心的局部评估过程，而不是重新映射和评估显示器中所有物体的位置。在三个实验中，我们通过测量扫视目标和可变数量的非扫视目标在扫视过程中的位移检测阈值，研究了除扫视目标之外的物体是否也会影响感知稳定性。我们发现，多个物体的位置在扫视过程中得以保持，但精度各不相同，扫视目标物体在位移感知方面具有优先权，这很可能是因为它在扫视之前是注意力的焦点，并且在扫视之后位于中央凹附近。非扫视目标物体的位移感知受到视敏度限制、注意力限制和记忆容量限制的影响。与之前发现扫视后空白有助于提高扫视过程中位移方向检测的研究不同，我们发现扫视后消隐会增加误报，从而损害位移本身的检测。总体而言，我们的结果与视觉工作记忆是扫视过程中稳定性感知基础的假设一致。
