Is there any evidence that this is present in the common ancestor an is not a new development of the chimpanzees/bonobos?
I wouldn't want to make strong claims on the size of the difference based on an N=3, but it's certainly sufficient as an existence proof, especially since the humans are performing near ceiling.
Just kidding, btw, but I recall having heard something along this.
[I can blame my native language that is Spanish, where the words apes and monkeys are equivalent. Anyway, in the recent times it's more common to try to use each word for the different kinds of animals like in English. It's a good excuse, but the reality is that I was wrong.]