So says those forever questing after the 'missing link.'
According to the article, tickling a primate will, as it does in humans, evoke laughter; or,at least, something akin to the human equivalent.
The 'experts' did as they are wont to do in these situations and released a statement of glowing praise:
Experts praised the work. It gives very strong evidence that ape and human laughter are related through evolution...
Well, dogs smile. Humans smile. I wonder what the 'experts' make of that.