No, this is not a ‘Ha Ha Bonk’ joke.
Australian optometrist has discovered that laughing makes your brain go funny. Prof. Pettigrew is a jovial chap who happens to be director of Queensland Uni’s Vision Thing. He noticed that laughter stops binocular rivalry illusions/phenomena.
If your eyes see different images, normally your visual experience alternates between the two, but laughter blends them. If your left eye sees some vertical stripes/bars and your right eye see horizontal ones, your visual experience is normally of one then the other and so on. If you happen to be laughing then you would see a grid.
He goes onto claim that the same would hold for good old Necker Cube. But he has done the experiment and I wonder. First off, being a vision bod, I presume he knows that Necker cube illusion is not a phenomenon of binocular rivalry. More interestingly while Bin. Riv. is a classic bottom up kind of a thing, the Neck. Cu. appears to be far more of a top-down kind of thing. (See Meng & Tong, 2004 [here])
As a fan of jokes and Necker Cube I’d be very interested if this result does extend. But I’ll believe it when I see it!