illuminating science

I find neuroscience, the study of the brain and its functioning (e.g., this year’s Psychology Ig Nobel.) to be a fascinating topic. At the University of Queensland, we’re lucky enough to have Jack Pettigrew, an amazing scientist, who is researching (among other things) perceptual rivalry and interhemispheric switching. His website has a lot of information, so I’ll try and summarise what I know here, including things I learned from one of his talks.

Perceptual rivalry refers to the phenomena of being presented with an image which has two possible interpretations, but where you can only see one at a time. The simplest example is the Necker cube - which “side” is the top of the cube? You will probably see it switching from leaning to the left or to right, every few seconds. Try as you might, you probably won’t be able to see both at once! Jack Pettigrew has a tonne of demos on his site. A few of my favourites are:

• The reversible sphere - which way is it rolling? Keep watching! If you think there’s a trick, get a friend to watch with you, and you can both say which direction it’s going in and when it changes - bet you won’t always agree!
• An animated Necker cube
• Boneh’s Illusion - watch the blue dots, and see what happens to the yellow dots. Some or all of them should periodically disappear and reappear! If they don’t, “try again when you are in a “better mood” (disappearance increases with euphoria), or at a different time of day.” Some of his thoughts on it are .
• Dali’s Slave Market/Voltair. Can you see both of the title images? (hint: there’s a skull in one of them!)

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Next post will describe Jack Pettigrew’s theories of perceptual rivalry and interhemispheric switching!