[youtube https://www.youtube.com/watch?v=LqR179VT8tk&w=560&h=315] A new National Geographic video examines what laughter can do for human health. Psychology Professor Robert Provine appears in the video and provides insight on the origins of laughter, saying it begins at three to four months of age and is one of the most important forms of early communication between babies and mothers. “It’s a kind of instinctive language that exists before we learn to talk. Laughter, like speech, evolved to change the behavior of other individuals,” Provine said. “Does [laughter] have to have other purposes? It probably does, but we’re just now starting to tease out what those …