Shirama Aya, Ishiguchi Akira
Graduate School of Humanities aod Sciences, Department of Psychology, Ochanomizu University, Ohtsuka, Bunkyo-ku, Tokyo 112-8610, Japan.
Shinrigaku Kenkyu. 2009 Aug;80(3):223-31. doi: 10.4992/jjpsy.80.223.
This study investigated retinal eccentricity effects in visual search. We introduced several scaling methods for the spatial resolution gradient (SRG) of the visual field induced by retinal properties. Each of stimuli in a single trial was presented at various eccentricities instantaneously. In M-scaling, the stimuli were gradually magnified as increasing eccentricity to compensate for the peripheral reduction in spatial resolution (Rovamo & Virsu, 1979). In Unscaling and D-scaling, the minimum and maximum sizes in M-scaling were used respectively regardless of eccentricity. D-scaling improved the visibility of peripheral stimuli while preserving the SRG. Using a search asymmetry for notched and complete squares, we arranged two tasks with different degrees of target discriminability. The search performance of both tasks became increasingly less efficient as the target appeared at more distant eccentricities in Unscaling, but M-scaling reduced the eccentricity effect. However, D-scaling produced efficient search for the salient target regardless of eccentricity, but held the eccentricity effect in the difficult search. On the SRG, the visual system seems to achieve a balance between simultaneous visual sampling over a wide field of vision and attentional prioritization of central vision.
本研究调查了视觉搜索中的视网膜离心率效应。我们介绍了几种由视网膜特性引起的视野空间分辨率梯度（SRG）的缩放方法。在单次试验中，每个刺激瞬间呈现于不同的离心率处。在M缩放中，随着离心率增加，刺激逐渐放大，以补偿周边空间分辨率的降低（罗瓦莫和维尔苏，1979）。在无缩放和D缩放中，无论离心率如何，分别使用M缩放中的最小和最大尺寸。D缩放提高了周边刺激的可见性，同时保留了SRG。利用带缺口正方形和完整正方形的搜索不对称性，我们安排了两个具有不同目标可辨别程度的任务。在无缩放中，随着目标出现在更远的离心率处，两个任务的搜索性能效率越来越低，但M缩放减少了离心率效应。然而，D缩放无论离心率如何，都能对显著目标进行高效搜索，但在困难搜索中保持了离心率效应。在SRG上，视觉系统似乎在广阔视野的同时视觉采样与中央视觉的注意力优先级之间实现了平衡。
