The importance of high-acuity foveal vision to visual search can be assessed by denying foveal vision using the gaze-contingent Moving Mask technique. Foveal vision was necessary to attain normal performance when searching for a target letter in alphanumeric displays, Perception & Psychophysics, 62 (2000) 576–585. In contrast, foveal vision was not necessary to correctly locate and identify medium-sized target objects in natural scenes, Journal of Experimental Psychology: Human Perception and Performance, 40 (2014) 342–360. To explore these task differences, we used grayscale pictures of real-world scenes which included a target letter (Experiment 1: T, Experiment 2: T or L). To reduce between-scene variability with regard to target salience, we developed the Target Embedding Algorithm (T.E.A.) to place the letter in a location for which there was a median change in local contrast when inserting the letter into the scene. The presence or absence of foveal vision was crossed with four target sizes. In both experiments, search performance decreased for smaller targets, and was impaired when searching the scene without foveal vision. For correct trials, the process of target localization remained completely unimpaired by the foveal scotoma, but it took longer to accept the target. We reasoned that the size of the target may affect the importance of foveal vision to the task, but the present data remain ambiguous. In summary, the data highlight the importance of extrafoveal vision for target localization, and the importance of foveal vision for target verification during letter-in-scene search.

高敏锐度中央凹视力对视觉搜索的重要性可以通过使用凝视视情况移动蒙版技术否认中央凹视力来评估。在字母数字显示中搜索目标字母时，中央凹视力是获得正常表现所必需的，Perception & Psychophysics, 62 (2000) 576–585。相比之下，中央凹视觉对于在自然场景中正确定位和识别中等大小的目标物体不是必需的，Journal of Experimental Psychology: Human Perception and Performance, 40 (2014) 342–360。为了探索这些任务差异，我们使用了包含目标字母的真实场景的灰度图片（实验 1：T，实验 2：T 或 L）。为了减少关于目标显着性的场景间可变性，我们开发了目标嵌入算法（TEA ) 将字母放置在将字母插入场景时局部对比度发生中值变化的位置。中心凹视力的存在与否与四种目标尺寸交叉。在这两个实验中，较小目标的搜索性能下降，并且在没有中央凹视力的情况下搜索场景时会受到影响。对于正确的试验，目标定位过程仍然完全不受中心凹暗点的影响，但接受目标需要更长的时间。我们推断目标的大小可能会影响中央凹视觉对任务的重要性，但目前的数据仍然不明确。总之，数据突出了中心凹视觉对目标定位的重要性，以及在场景中的字母搜索过程中中心凹视觉对目标验证的重要性。