Optical illusions are not universal, and the differences in how we perceive them can help us to understand cognition. The famous Müller-Lyer illusion is not universal, but differs by culture, with some African tribes unable to see the illusion at all - possibly because of differences in environment. Individuals with autism seem less sensitive to the Sheppard's table illusion, which might help improve an understanding of the condition. Differences in responses are possible because different illusions trick your brain in different ways. BBC has a great history of the evolution of optical illusions, and, finally, here are some auto-kinectic illusions, because they are awesome.
Apollo Robbins is a spectacular pickpocket whose work extends to neuroscience, the military and magic.
Have you ever wondered why you don't see motion blur when your eyes flick to a new position? Why, if you sit in front of a mirror and watch yourself, you never see your eyes move? That is saccadic masking, one of the lies your brain tells to avoid confusing you. Have you noticed that the first tick after glancing at a clock with a second hand can take more than one second? No, it's not just you! That's a related phenomenon called chronostasis, or more commonly the stopped clock illusion.
The average human eye has three types of cone cells, each of which is sensitive to a different wavelength range of visible light. The difference in the relative signal from the three cones allows us to distinguish colors. Unfortunately, since these sensitivity ranges overlap, there are some combinations of signals from the cones that can't be created by light emitted from a real object. These are the so-called "imaginary colors". However, by selectively overstimulating one or more types of cone, we can still perceive these colors; this is the principle behind the Eclipse of Titan, an optical illusion which produces both a green and a cyan that don't otherwise appear in nature. (Similar effects can be seen in the Eclipses of Mars, Neptune, and Triton.) [more inside]
If I Were You: Perceptual Illusion of Body Swapping. Expanding on previous experiments, researchers discover how to induce a "body-swap" illusion, whereby subjects perceive the body of another as if it were their own.
Of Jock Straps and Conspiracy Theories. A new study looks at how lacking control increases the tendency for magical thinking and illusory pattern perception. [Via]
Is the dancer spinning clockwise or counterclockwise? An optical illusion. [more inside]
Virtual Out-of-Body Experience. Using two procedures to deliberately scramble a person's visual and tactile senses, neuroscientists are able to induce "out-of-body" experiences in people. The effect is the same as the 'rubber hand illusion', but extends the effect to the whole body instead of just one limb (you can try the hand illusion for yourself).
Your daily dose of perception-bending. Stare at the center of this video (wmv or flash) for a minute or two then look away from the screen at your surroundings. You'll experience an interesting and somewhat disconcerting effect. Not appropriate for anyone prone to headaches or seizures.
Carnegie Mellon researchers have created a program that can automatically generate a 3-D model from a single photograph, using machine learning. Take a look at this high-res comparison of original and generated images, also demonstration animations and downloadable videos (with executables). [via /. see also: a little on human 3d perception at everything2, groovy dragon illusion]
Masters of Deception "There are a number of incredible artistic works featured in Masters of Deception, which require movement to appreciate their full impact. Additionally, I had in my possession various interviews with some of the book's featured artists that I wanted to share with my readership. Unfortunately, the publisher was unwilling to produce a CD to accompany the book. I have created this web site, therefore, to augment and enhance the reader's experience by presenting those works and interviews that I could not present in book form." Al Seckel. enjoy.
Red and green dots have never been so interesting. At least to a geek like me. I love it when my brain plays tricks on me.
Remember the weirdness with Bush's hypnotic rainbow tie last week? Now you too can experiment with creating mesmerizing patterns on Project LITE's Moire page.
[via j-walk blog]
[via j-walk blog]