It's quite possible that new information has come to light. However, the most recent information I have read, which continued to repeat the information I learned at the university, stated that chimps did not care if another chimp was treated unjustly. Let me give you a scenario. It was originally done with Capuchin monkeys but was repeated with chimps. Chimp Joe and Chimp Jay are in adjoining cages. They have been taught that if they exchange a rock they will get a treat. The lab worker comes in, and both chimps go to it. The worker begins by rewarding both with cucumber slices (which are mostly water). Everyone is happy and content. But then things change. In the next round, the worker rewards Chimp Joe with a grape (a much sweeter and heartier treat) and still gives Chimp Jay a cucumber slice. Chimp Jay now feels cheated and throws the cucumber slice out of the cage. He'll have none of it! It's not fare!!! Now, here is the question: is there any indication that Chimp Joe gives a squat about the unfairness to Chimp Jay? Does he go over to comfort Jay? Does he set aside one of his grapes and share it? Absolutely not. Chimps only care about justice when its concerns themselves. At least, that is true to the best of my knowledge.
Here is website that not only has the Capuchin video, but also discusses a followup study where chimps were used instead, and it was repeated a second time using a mechanical feeder. The food refusal was severe when the food was given by a live lab assistant, meaning that the chimp understood that the inequity was do to a moral agent. Again, you see no sign of compassion or sharing from the second chimp.
Do chimpanzees really care about equity? - International Cognition and Culture Institute
