CiNNeR
[The monkey test subjects] normally like cucumbers just fine. So we compared that to a control where both of them were trading and getting a cucumber and they were more than happy to eat those cucumber pieces when both they and their partner were getting a cucumber. And in another control we controlled to see what happened if the grapes were visible but no one was getting them. So that, control was actually particularly mean. We would wave the grapes in front of their faces until they gestured towards it. And then when they gestured we would put the grape down and we would give them the cucumber. But importantly, we did the same thing for both monkeys. So they both ended up getting the cucumber and in both cases they accepted and ate their cucumbers most of the time. Whereas, when their partner got a grape, they were much more likely to refuse their cucumber, which suggests that they aren't as enthusiastic about those cucumbers when their partner is getting something better.