Only humans are smart enough to devise a test to prove that chimps are smarter.

My local news channel ran a segment on this story. and it ended like this:

Newsperson 1: It sounds to me like they were just monkeying around!

Newspeople 2, 3, and 4: Oh! Roberta!

Newspeople 1, 2, 3 and 4: Hahahahahahahahah!

So I think this proves that chimps are at least smarter than newspeople.