I will try to look for that experiment if you think it is a good example. But also try to think about some points!

-How was it possible that some partially civilized evovled apes are putting RATS into cages just to check their altruism ?.

-In 1974 a really interesting book was published Egoistic Gene by Richard Dawkins. I would advise you read it if you have the time, it explains a lot about altruism and our species.

-I think you missed the point of my comment, which I believe lies in the last lines of it

Have a good day!