A common visual metric for approximate number and density
A common visual metric for approximate number and density
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DOI：
10.1073/pnas.1113195108
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发表时间：
2011-12-06
影响因子：
11.1
通讯作者：
Morgan, Michael J.
中科院分区：
文献类型：
--
作者：
Dakin, Steven C.;Tibber, Marc S.;Morgan, Michael J.
在大量关于如何估计物体密度（即间隔）的文献中，人们对人类如何估计场景中物体的数量非常感兴趣。在这里，我们展示了我们的数字感和密度感是交织在一起的。当出现两个斑块时，观察者发现当这些斑块的总体尺寸不匹配时，很难发现密度或数量上的差异，并且他们的误差与较大的斑块出现的密度和数量一致。我们建议使用调谐到低和高空间频率（SF）的机制的相对响应来估计密度，因为高SF的能量在很大程度上取决于物体的数量，而低SF能量更多地取决于元素占用的面积。与人类观察者一样，这种测量方法也会受到总体刺激大小的影响，通过使用与相对刺激大小相同的测量方法来估计数量，我们可以解释所有的结果。这个模型是一个简单的，生物学上合理的感知数量和密度的通用度量。
There is considerable interest in how humans estimate the number of objects in a scene in the context of an extensive literature on how we estimate the density (i.e., spacing) of objects. Here, we show that our sense of number and our sense of density are intertwined. Presented with two patches, observers found it more difficult to spot differences in either density or numerosity when those patches were mismatched in overall size, and their errors were consistent with larger patches appearing both denser and more numerous. We propose that density is estimated using the relative response of mechanisms tuned to low and high spatial frequencies (SFs), because energy at high SFs is largely determined by the number of objects, whereas low SF energy depends more on the area occupied by elements. This measure is biased by overall stimulus size in the same way as human observers, and by estimating number using the same measure scaled by relative stimulus size, we can explain all of our results. This model is a simple, biologically plausible common metric for perceptual number and density.