An object's processing is impaired by the presence of nearby clutter. Several distinct mechanisms, such as masking and visual crowding, are thought to contribute to such flanker-induced interference. It is therefore important to determine which mechanism is operational in any given situation. Previous studies have proposed that the in-out asymmetry (IOA), where a peripheral flanker interferes with the target more than a foveal flanker, is diagnostic of crowding. However, several studies have documented inconsistencies in the occurrence of this asymmetry, particularly at locations beyond the horizontal meridian, casting doubt on its ability to delineate crowding. In this study, to determine if IOA is diagnostic of crowding, we extensively charted its properties. We asked a relatively large set of participants (n = 38) to identify a briefly presented peripheral letter flanked by a single inward or outward letter at one of four locations. We also manipulated target location uncertainty and attentional allocation by blocking, randomizing or pre-cueing the target location. Using multilevel Bayesian regression analysis, we found robust IOA at all locations, although its strength was modulated by target location, location uncertainty, and attentional allocation. Our findings suggest that IOA can be an excellent marker of crowding, to the extent that it is not observed in other flanker-interference mechanisms, such as masking.

中文翻译：

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表征视觉拥挤中的进出不对称。


物体的处理会因附近杂物的存在而受到损害。多种不同的机制，例如掩蔽和视觉拥挤，被认为是造成这种侧翼干扰的原因。因此，确定在任何特定情况下哪种机制可以运行非常重要。先前的研究提出，内向外不对称（IOA），即周边侧翼比中央凹侧翼对目标的干扰更大，是拥挤的诊断。然而，一些研究记录了这种不对称现象的不一致，特别是在水平子午线以外的位置，这让人对其描绘拥挤的能力产生怀疑。在这项研究中，为了确定 IOA 是否可以诊断拥挤，我们广泛绘制了其特性图表。我们要求相对较多的参与者（n = 38）在四个位置之一识别一个简短呈现的外围字母，其两侧有一个向内或向外的字母。我们还通过阻止、随机化或预先提示目标位置来操纵目标位置的不确定性和注意力分配。使用多级贝叶斯回归分析，我们发现所有位置都有稳健的 IOA，尽管其强度受到目标位置、位置不确定性和注意力分配的调节。我们的研究结果表明，IOA 可以成为拥挤的一个很好的标志，在某种程度上，在其他侧翼干扰机制（例如掩蔽）中没有观察到它。