Mechanisms for perception of numerosity or texture-density are governed by crowding-like effects.
Mechanisms for perception of numerosity or texture-density are governed by crowding-like effects.
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DOI：
10.1167/15.5.4
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发表时间：
2015
影响因子：
1.8
通讯作者：
Burr DC
中科院分区：
文献类型：
--
作者：
Anobile G;Turi M;Cicchini GM;Burr DC
我们最近提供的证据表明，数量和纹理密度的感知是由两个独立的机制介导的：在相对较低的数字，服从韦伯定律，和纹理密度机制在较高的数字，下面的平方根定律。在这项研究中，我们调查了这两种机制之间的切换是否取决于隔离单个点的能力，因此遵循类似的法律，那些管理视觉拥挤。我们测量了在三个偏心率范围广泛的数字识别。我们发现，该点的数量制度（韦伯定律）让位于密度制度（平方根定律）取决于偏心率。在中心视觉中，该制度以2.3点/°2变化，而在15°偏心率下，其以0.5点/°2变化，密度低三倍。因此，阈值低numerosities增加偏心率，而在较高的numerosities阈值保持不变。我们进一步表明，像拥挤，政权的变化是独立的点的大小，取决于点中心之间的距离，而不是点边缘之间的距离或油墨覆盖。性能不受刺激对比度或模糊，表明过渡不依赖于低水平的刺激属性。我们的研究结果加强了这样一个概念，即数量和纹理是由两个不同的过程介导的，这取决于单个元素是否是感知隔离。哪一种机制是按照决定拥挤的规律进行的。
We have recently provided evidence that the perception of number and texture density is mediated by two independent mechanisms: numerosity mechanisms at relatively low numbers, obeying Weber's law, and texture-density mechanisms at higher numerosities, following a square root law. In this study we investigated whether the switch between the two mechanisms depends on the capacity to segregate individual dots, and therefore follows similar laws to those governing visual crowding. We measured numerosity discrimination for a wide range of numerosities at three eccentricities. We found that the point where the numerosity regime (Weber's law) gave way to the density regime (square root law) depended on eccentricity. In central vision, the regime changed at 2.3 dots/°2, while at 15° eccentricity, it changed at 0.5 dots/°2, three times less dense. As a consequence, thresholds for low numerosities increased with eccentricity, while at higher numerosities thresholds remained constant. We further showed that like crowding, the regime change was independent of dot size, depending on distance between dot centers, not distance between dot edges or ink coverage. Performance was not affected by stimulus contrast or blur, indicating that the transition does not depend on low-level stimulus properties. Our results reinforce the notion that numerosity and texture are mediated by two distinct processes, depending on whether the individual elements are perceptually segregable. Which mechanism is engaged follows laws that determine crowding.