Capuchins are a New World Monkey that are closely related to us. Humans and capuchins last shared a common ancestor roughly 30 million years ago (Fragaszy et al., 2004). These social primates live in large groups with dominance hierarchies. To learn more about this species, including their behavior, click here.
|C. apella Photo: John Mittermeier|
Intentions don't seem to matter if you're a scorned capuchin. Capuchins punish the low-ranking individual even when that individual was not to blame for the unequal distribution of food. As Leimgruber stated when interviewed for Phys.org, capuchin monkeys appear to have a sort of "If I can't have it, no one can"attitude.
Similar inequality studies have been conducted with chimpanzees, our closest living relatives. When we think of chimpanzees in comparison to capuchins, chimpanzees may seem more ruthless. They will kill one another and they've been observed going to "war" with other troops of chimpanzees. Yet, chimpanzees will only make an effort to punish if the other individual is responsible for the inequality (Riedl et al., 2012). Perhaps capuchins are the anomaly or maybe this spiteful behavior does have its evolutionary origins 30 million years ago, making chimpanzees the anomaly. Similar studies will need to be done in other primate species to better understand the evolutionary history of this trait in primates.
Of course, we can't actually blame capuchins for our spiteful actions (nor should we: let's not forget the power of human agency), but this study adds to our knowledge of human behavior while, perhaps, raising more questions.
Links of potential interest:
Video of capuchin fairness test
Frans de Waal Ted Talk on Moral Behavior
Fragaszy, D. M., Visalberghi, E., & Fedigan, L. M. (2004). The complete capuchin: the biology of the genus Cebus. Cambridge University Press.
Leimgruber, K. L., Rosati, A. G., & Santos, L. R. (2015). Capuchin monkeys punish those who have more. Evolution and Human Behavior.
Riedl, K., Jensen, K., Call, J., & Tomasello, M. (2012). No third-party punishment in chimpanzees. Proceedings of the National Academy of Sciences, 109(37), 14824-14829.