Although humans tend to be risk averse, gambling, an inherently risky behavior, remains exceedingly popular and is an increasingly legal activity. The advent of electronic and online gambling games has further exacerbated the risk of gambling addiction. Given the frequently disadvantageous results of gambling, it is important to explore its evolutionary roots to understand why some individuals engage in gambling and other risky activities that may be detrimental. Inspired by the Primate Gambling Task, a modification of the Iowa Gambling Task developed by Proctor et al. (2014), we presented zoo-housed chimpanzees, gorillas, and Japanese macaques with a choice between two stimuli on a touchscreen, one representing a low-value, low variance (LV) option and the other a high-value, high variance (HV) option. Subjects completed three conditions in which the LV always resulted in a low or middle-value food reward. In each condition, stimuli colors varied and selecting the HV resulted in differing probabilities of both receiving any reward and the subject’s high-value reward. In a second experiment, subjects chose between a picture of a middle-value food and one of the six HV or LV stimuli to test their relative preferences for these stimuli in a novel context. Using several analyses, we found substantial within-species variation in both experiments, but relatively minimal between-species differences. Analyses did not always result in the same conclusions, however, no subject, regardless of species, learned to prefer the HV option in experiment 1, if any learning occurred at all. In experiment 2, nearly all subjects showed a preference for images of middle-value foods compared to the six HV and LV stimuli. As with much human risk-preference research, individual differences suggest that much of the variation in risk-taking behavior lies at the individual rather than species level, at least among the three primate species tested here.

尽管人类倾向于规避风险，但赌博是一种固有的冒险行为，仍然非常流行，并且是一种越来越合法的活动。电子和在线赌博游戏的出现进一步加剧了赌博成瘾的风险。鉴于赌博经常带来不利的结果，因此重要的是探索其进化根源，以了解为什么有些人从事赌博和其他可能有害的危险活动。受灵长类赌博任务启发，Proctor等人开发的爱荷华州赌博任务的修改版。（2014），我们介绍了动物园饲养的黑猩猩，大猩猩和日本猕猴，可以在触摸屏上选择两种刺激，一种代表低价值，低方差（LV）选项，另一种代表高价值，高方差（ HV）选项。受试者完成了三个条件，在这些条件下左室总是导致低或中值的食物奖励。在每种情况下，刺激颜色各不相同，选择HV​​导致获得任何奖励和受试者的高价值奖励的概率不同。在第二个实验中，受试者在中等价值食物的图片和六个HV或LV刺激之一之间进行选择，以测试他们在新颖背景下对这些刺激的相对偏好。通过多次分析，我们发现两个实验中的种内差异很大，但种间差异相对较小。分析并不总是得出相同的结论，但是，如果有任何学习发生，则没有受试者，无论物种如何，都不会在实验1中学会偏爱HV选项。在实验2中，与六种HV和LV刺激相比，几乎所有受试者都偏爱中价食品的图像。与许多人类风险偏好研究一样，个体差异表明，冒险行为的许多变化都发生在个体而不是物种层面，至少在这里测试的三个灵长类物种中。