This experiment, listed in one table and in the references but not discussed elsewhere, would suggest otherwise: https://www.youtube.com/watch?v=meiU6TxysCg htt

This experiment, listed in one table and in the references but not discussed elsewhere, would suggest otherwise: https://www.youtube.com/watch?v=meiU6TxysCg https://www.youtube.com/watch?v=meiU6TxysCg There might be other confounding factors in that experiment, but for the life of me I can't imagine what they would be. My stats knowledge has evaporated over the years so I can't follow exactly what the study is doing to come to their conclusion, but it strains my credulity to suggest that the monkeys in that experiment aren't angry about perceived inequity. I'd be interested to know if anyone can do a TLDR of the study as to why they reached that conclusion in the face of what looks like pretty compelling evidence. Edit: Now I come to think about it, I suppose a counter-argument is that the angry monkey just knows that the experimenter has grapes and they're angry they're not getting them, rather than being angry that the other monkey is getting grapes while they're not. Feels like that argument makes sense given our tendency to anthropomorphise animals, particularly primates.