Disentangling signal from noise in visual contrast discrimination
Disentangling signal from noise in visual contrast discrimination
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DOI：
10.1038/nn741
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发表时间：
2001-11-01
影响因子：
25
通讯作者：
Sagi, D
中科院分区：
文献类型：
--
作者：
Gorea, A;Sagi, D
人类检测刺激变化的能力(DeltaC)随着参考水平(C)的增加而降低。由于检测性能反映了相关感觉大脑模块的信噪比，这种行为可以用两种极端的方式解释：第一，由常数DeltaC引起的内部反应变化Deltar随C减小(即换能器R=f(C)呈现压缩非线性)，而内部噪声与R无关；第二，Deltar随C恒定，但噪声水平随R增加。新发现的对人类决策的约束有助于解决这个百年来的问题：在以相同概率发生多个变化的检测任务中，观察者使用唯一的反应标准来确定是否发生了变化。对于对比度辨别，我们的结果支持上面的第一个描述：人类的表现受到对比度换能器的非线性和几乎恒定的噪声的限制。
Human ability to detect stimulus changes (DeltaC) decreases with increasing reference level (C). Because detection performance reflects the signal-to-noise ratio within the relevant sensory brain module, this behavior can be accounted for in two extreme ways: first, the internal response change DeltaR evoked by a constant DeltaC decreases with C (that is, the transducer R = f(C) displays a compressive nonlinearity), whereas the internal noise is independent of R; second, DeltaR is constant with C but the noise level increases with R. A newly discovered constraint on human decision-making helps solve this century-old problem: in a detection task where multiple changes occur with equal probabilities, observers use a unique response criterion to decide whether a change has occurred. For contrast discrimination, our results supported the first account above: human performance was limited by the contrast transducer nonlinearity and an almost constant noise.