Graham Daniel, Schwarz Bianca, Chatterjee Anjan, Leder Helmut
Department of Psychology, Hobart and William Smith Colleges, United States.
Faculty of Psychology, University of Vienna, Austria.
Vision Res. 2016 Mar;120:11-21. doi: 10.1016/j.visres.2015.03.018. Epub 2015 Apr 11.
Natural scene luminance distributions typically have positive skew, and for single objects, there is evidence that higher skew is a correlate (but not a guarantee) of glossiness. Skewness is also relevant to aesthetics: preference for glossy single objects (with high skew) has been shown even in infants, and skewness is a good predictor of fruit freshness. Given that primate vision appears to efficiently encode natural scene luminance variation, and given evidence that natural scene regularities may be a prerequisite for aesthetic perception in the spatial domain, here we ask whether humans in general prefer natural scenes with more positively skewed luminance distributions. If humans generally prefer images with the higher-order regularities typical of natural scenes and/or shiny objects, we would expect this to be the case. By manipulating luminance distribution skewness (holding mean and variance constant) for individual natural images, we show that in fact preference varies inversely with increasing positive skewness. This finding holds for: artistic landscape images and calibrated natural scenes; scenes with and without glossy surfaces; landscape scenes and close-up objects; and noise images with natural luminance histograms. Across conditions, humans prefer images with skew near zero over higher skew images, and they prefer skew lower than that of the unmodified scenes. These results suggest that humans prefer images with luminances that are distributed relatively evenly about the mean luminance, i.e., images with similar amounts of light and dark. We propose that our results reflect an efficient processing advantage of low-skew images over high-skew images, following evidence from prior brain imaging results.
自然场景的亮度分布通常呈正偏态，对于单个物体而言，有证据表明更高的偏态与光泽度相关（但并非保证）。偏态也与美学相关：即使在婴儿中也已显示出对有光泽的单个物体（具有高偏态）的偏好，并且偏态是水果新鲜度的良好预测指标。鉴于灵长类动物的视觉似乎能有效地编码自然场景的亮度变化，并且有证据表明自然场景的规律性可能是空间领域审美感知的先决条件，在此我们探究人类总体上是否更喜欢亮度分布更呈正偏态的自然场景。如果人类总体上更喜欢具有自然场景和/或闪亮物体典型的高阶规律性的图像，我们预期会是这种情况。通过操纵单个自然图像的亮度分布偏态（保持均值和方差不变），我们表明实际上偏好随正偏态的增加而呈反比变化。这一发现适用于：艺术风景图像和校准后的自然场景；有和没有光泽表面的场景；风景场景和特写物体；以及具有自然亮度直方图的噪声图像。在各种条件下，人类更喜欢偏态接近零的图像而非高偏态图像，并且他们更喜欢比未修改场景的偏态更低的图像。这些结果表明人类更喜欢亮度围绕平均亮度相对均匀分布的图像，即具有相似明暗程度的图像。我们提出，根据先前脑成像结果的证据，我们的结果反映了低偏态图像相对于高偏态图像的有效处理优势。
