Jacobs G H
Folia Primatol (Basel). 1977;28(3):231-40. doi: 10.1159/000155812.
In a test situation where choice was not tied to reinforcement, both squirrel monkeys (Saimiri sciureus) and owl monkeys (Aotus trivirgatus) consistently chose to view the more luminant of a pair of lights. Over a two log unit range of luminance, the degree of preference in both species for the brighter of two lights was found to depend on their difference in luminance and not on their actual luminances.
在一种选择与强化无关的测试情境中，松鼠猴（松鼠猴属）和夜猴（三带夜猴）都始终选择观看一对灯光中亮度更高的那个。在两个对数单位的亮度范围内，发现这两个物种对两盏灯中较亮者的偏好程度取决于它们的亮度差异，而不是它们的实际亮度。
