Data from: Experimental evidence that primate trichromacy is well suited for detecting primate social colour signals

Primate trichromatic colour vision has been hypothesized to be well tuned for detecting variation in facial coloration, which could be due to selection on either signal wavelengths or the sensitivities of the photoreceptors themselves. We provide one of the first empirical tests of this idea by asking whether, when compared with other visual systems, the information obtained through primate trichromatic vision confers an improved ability to detect the changes in facial colour that female macaque monkeys exhibit when they are proceptive. We presented pairs of digital images of faces of the same monkey to human observers and asked them to select the proceptive face. We tested images that simulated what would be seen by common catarrhine trichromatic vision, two additional trichromatic conditions and three dichromatic conditions. Performance under conditions of common catarrhine trichromacy, and trichromacy with narrowly separated LM cone pigments (common in female platyrrhines), was better than for evenly spaced trichromacy or for any of the dichromatic conditions. These results suggest that primate trichromatic colour vision confers excellent ability to detect meaningful variation in primate face colour. This is consistent with the hypothesis that social information detection has acted on either primate signal spectral reflectance or photoreceptor spectral tuning, or both.

已有假说提出，灵长类三色视觉（trichromatic colour vision）可高度适配面部色彩变化的检测，该适配性或源于对信号波长的选择，亦或感光细胞自身的敏感性调整。本研究针对这一假说开展了首批实证检验之一：通过对比不同视觉系统获取的视觉信息差异，探究灵长类三色视觉是否能提升检测雌性猕猴动情接受期面部色彩变化的能力。我们向人类观察者呈现同一猕猴的成对面部数字图像，并要求其选出处于动情接受期的图像。本次实验共测试了模拟以下六种视觉条件的图像：典型狭鼻猴类（catarrhine）三色视觉、另外两种三色视觉条件，以及三种二色视觉条件。在典型狭鼻猴类三色视觉，以及长波-中波视锥色素（LM cone pigments）间距较窄（该类型常见于雌性阔鼻猴类（platyrrhines））的三色视觉条件下，观察者的识别表现均优于等间距三色视觉，或是任意一种二色视觉条件。上述结果表明，灵长类三色视觉可显著提升灵长类面部色彩的有效变化检测能力。该结果与以下假说相符：社会信息检测的进化选择压力，曾作用于灵长类信号的光谱反射特性，或是感光细胞的光谱调谐特性，亦或同时作用于两者。