Humans find members of the opposite sex more attractive when their image is spatially associated with the color red. This effect even occurs when the red color is not on the skin or clothing (i.e. is extraneous). We hypothesize that this extraneous color effect could be at least partially explained by a low-level and biologically innate generalization process, and so similar extraneous color effects should be observed in non-humans. To test this possibility, we examined the influence of extraneous color in rhesus macaques (Macaca mulatta). Across two experiments, we determined the influence of extraneous red on viewing preferences (assessed by looking time) in free-ranging rhesus monkeys. We presented male and female monkeys with black and white photographs of the hindquarters of same and opposite sex conspecifics on either a red (experimental condition) or blue (control condition) background. As a secondary control, we also presented neutral stimuli (photographs of seashells) on red and blue backgrounds. We found that female monkeys looked longer at a picture of a male scrotum, but not a seashell, on a red background (Experiment 1), while males showed no bias. Neither male nor female monkeys showed an effect of color on looking time for female hindquarters or seashells (Experiment 2). The finding for females viewing males suggests that extraneous color affects preferences among rhesus macaques. Further, it raises the possibility that evolutionary processes gave rise to extraneous color effects during human evolution.

中文翻译：

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无关的颜色会影响雌性猕猴对雄性同种动物照片的注视偏好。


当异性的形象在空间上与红色相关时，人们会发现异性更具吸引力。即使红色不在皮肤或衣服上（即无关的），也会发生这种效果。我们假设这种无关的颜色效应至少可以部分地通过低水平和生物学先天的泛化过程来解释，因此在非人类中应该观察到类似的无关颜色效应。为了测试这种可能性，我们研究了外来颜色对恒河猴（Macaca mulatta）的影响。通过两项实验，我们确定了外来红色对自由放养的恒河猴观看偏好（通过观看时间评估）的影响。我们向雄性和雌性猴子展示了同性和异性同种后躯的黑白照片，背景为红色（实验条件）或蓝色（对照条件）。作为辅助控制，我们还在红色和蓝色背景上呈现中性刺激（贝壳照片）。我们发现，雌性猴子在红色背景下观看雄性阴囊的图片而不是贝壳的时间更长（实验 1），而雄性猴子则没有表现出任何偏见。雄性和雌性猴子都没有表现出颜色对寻找雌性后躯或贝壳的时间的影响（实验 2）。雌性观察雄性的发现表明，无关的颜色会影响恒河猴的偏好。此外，它提出了一种可能性，即进化过程在人类进化过程中产生了无关的颜色效应。