Faculty of Psychology and Education Sciences, University of Coimbra, Rua do Colégio Novo, 3000-115 Coimbra, Portugal.
Spinoza Centre for Neuroimaging, Meibergdreef 75, 1105 BK Amsterdam, the Netherlands.; Institute of Neuroscience and Psychology, University of Glasgow, 62 Hillhead Street, Glasgow G12 8QB, United Kingdom.
Neuroimage. 2021 May 15;232:117909. doi: 10.1016/j.neuroimage.2021.117909. Epub 2021 Feb 27.
Humans and animals rely on accurate object size perception to guide behavior. Object size is judged from visual input, but the relationship between an object's retinal size and its real-world size varies with distance. Humans perceive object sizes to be relatively constant when retinal size changes. Such size constancy compensates for the variable relationship between retinal size and real-world size, using the context of recent retinal sizes of the same object to bias perception towards its likely real-world size. We therefore hypothesized that object size perception may be affected by the range of recently viewed object sizes, attracting perceived object sizes towards recently viewed sizes. We demonstrate two systematic biases: a central tendency attracting perceived size towards the average size across all trials, and a serial dependence attracting perceived size towards the size presented on the previous trial. We recently described topographic object size maps in the human parietal cortex. We therefore hypothesized that neural representations of object size here would be attracted towards recently viewed sizes. We used ultra-high-field (7T) functional MRI and population receptive field modeling to compare object size representations measured with small (0.05-1.4°diameter) and large objects sizes (0.1-2.8°). We found that parietal object size preferences and tuning widths follow this presented range, but change less than presented object sizes. Therefore, perception and neural representation of object size are attracted towards recently viewed sizes. This context-dependent object size representation reveals effects on neural response preferences that may underlie context dependence of object size perception.
人类和动物依赖于准确的物体大小感知来指导行为。物体大小是从视觉输入判断的，但物体的视网膜大小与其实际大小之间的关系随距离而变化。当视网膜大小发生变化时，人类感知物体大小相对恒定。这种大小恒常性补偿了视网膜大小与实际大小之间的可变关系，利用同一物体最近的视网膜大小的上下文来偏向于其可能的实际大小。因此，我们假设物体大小感知可能会受到最近观看的物体大小范围的影响，吸引感知到的物体大小接近最近观看的大小。我们证明了两种系统性偏见：一种是中央趋势，吸引感知大小接近所有试验的平均大小；另一种是序列依赖，吸引感知大小接近前一个试验呈现的大小。我们最近在人类顶叶皮层中描述了拓扑物体大小图。因此，我们假设这里的物体大小神经表示会被吸引到最近观看的大小。我们使用超高场（7T）功能磁共振成像和群体感受野建模来比较用小物体（0.05-1.4°直径）和大物体（0.1-2.8°）测量的物体大小表示。我们发现，顶叶物体大小偏好和调谐宽度遵循这个呈现范围，但变化小于呈现的物体大小。因此，物体大小的感知和神经表示被吸引到最近观看的大小。这种上下文相关的物体大小表示揭示了对神经反应偏好的影响，这些影响可能是物体大小感知的上下文依赖性的基础。
