Bays Paul M
University of Cambridge, Department of Psychology, Cambridge, CB2 3EB, UK.
Commun Psychol. 2024 Dec 19;2(1):125. doi: 10.1038/s44271-024-00173-7.
In our everyday experience, the sizes and weights of objects we encounter are strongly correlated. When objects are lifted, visual information about size can be combined with haptic feedback about weight, and a naive application of Bayes' rule predicts that the perceived weight of larger objects should be exaggerated and smaller objects underestimated. Instead, it is the smaller of two objects of equal weight that is perceived as heavier, a phenomenon termed the Size-Weight Illusion (SWI). Here we provide a normative explanation of the SWI based on principles of efficient coding, which dictate that stimulus properties should be encoded with a fidelity that depends on how frequently those properties are encountered in the environment. We show that the precision with which human observers estimate object weight varies as a function of both mass and volume in a manner consistent with the estimated joint distribution of those properties among everyday objects. We further show that participants' seemingly "anti-Bayesian" biases (the SWI) are quantitatively predicted by Bayesian estimation when taking into account the gradient of discriminability induced by efficient encoding. The related Material-Weight Illusion (MWI) can also be accounted for on these principles, with surface material providing a visual cue that changes expectations about object density. The efficient coding model is further compatible with a wide range of previous observations, including the adaptability of weight illusions and properties of "non-illusory" objects. The framework is general and predicts perceptual biases and variability in any sensory properties that are correlated in the natural environment.
在我们的日常体验中，我们所遇到物体的大小和重量紧密相关。当提起物体时，关于大小的视觉信息可以与关于重量的触觉反馈相结合，而对贝叶斯法则的简单应用预测，较大物体的感知重量会被夸大，较小物体的感知重量会被低估。相反，两个重量相等的物体中，较小的那个会被感知为更重，这一现象被称为大小 - 重量错觉（SWI）。在此，我们基于高效编码原则对SWI提供了一种规范性解释，该原则规定刺激属性应以取决于这些属性在环境中出现频率的保真度进行编码。我们表明，人类观察者估计物体重量的精度会随着质量和体积的变化而变化，其方式与日常物体中这些属性的估计联合分布一致。我们进一步表明，当考虑到由高效编码引起的可辨别性梯度时，贝叶斯估计能够定量预测参与者看似“反贝叶斯”的偏差（即SWI）。相关的材料 - 重量错觉（MWI）也可以基于这些原则得到解释，其中表面材料提供了一个视觉线索，改变了对物体密度的预期。高效编码模型还与之前的广泛观察结果相兼容，包括重量错觉的适应性和“非错觉”物体的属性。该框架具有普遍性，能够预测自然环境中任何相关感官属性的感知偏差和变异性。
