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Wei X, Stocker AA (2017) Lawful relation between perceptual bias and discriminability. Proceedings of the National Academy of Sciences USA, 114(38):10244-10249    
We present a law of human perception. The law expresses a mathematical relation between our ability to perceptually discriminate a stimulus from similar ones and our bias in the perceived stimulus value. We derived the relation based on theoretical assumptions about how the brain represents sensory information and how it interprets this information to create a percept. Our main assumption is that both encoding and decoding are optimized for the specific statistical structure of the sensory environment. We found large experimental support for the law in the literature, which includes biases and changes in discriminability induced by contextual modulation (e.g., adaptation). Our results imply that human perception generally relies on statistically optimized processes
Perception of a stimulus can be characterized by two fundamental psychophysical measures: how well the stimulus can be discriminated from similar ones (discrimination threshold) and how strongly the perceived stimulus value deviates on average from the true stimulus value (perceptual bias). We demonstrate that perceptual bias and discriminability, as functions of the stimulus value, follow a surprisingly simple mathematical relation. The relation, which is derived from a theory combining optimal encoding and decoding, is well supported by a wide range of reported psychophysical data including perceptual changes induced by contextual modulation. The large empirical support indicates that the proposed relation may represent a psychophysical law in human perception. Our results imply that the computational processes of sensory encoding and perceptual decoding are matched and optimized based on identical assumptions about the statistical structure of the sensory environment