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The Wisdom of Psychopaths
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The Neural Correlate Society recently announced the winners of its annual Best Visual Illusion contest. To celebrate the event, Mind Matters invited Susana Martinez-Conde and Stephen L. Macknik, two neuroscientists who specialize in visual perception, to explain the scientific value of visual illusions. This article is the first in a new Mind Matters series on the neuroscience of illusions.
View a slide show of illusions
It’s a fact of neuroscience that everything we experience is actually a figment of our imagination. Although our sensations feel accurate and truthful, they do not necessarily reproduce the physical reality of the outside world. Of course, many experiences in daily life reflect the physical stimuli that enter the brain. But the same neural machinery that interprets actual sensory inputs is also responsible for our dreams, delusions and failings of memory. In other words, the real and the imagined share a physical source in the brain. So take a lesson from Socrates: “All I know is that I know nothing.”
One of the most important tools used by neuroscientists to understand how the brain creates its sense of reality is the visual illusion. Historically, visual artists as well as illusionists have used visual illusions to develop deep insights into the inner workings of the visual system. Long before scientists were studying the properties of neurons, artists had devised a series of techniques to “trick” the brain into thinking that a flat canvas was three-dimensional, or that a series of brushstrokes was actually a still life.
Visual illusions are defined by the dissociation between the physical reality and the subjective perception of an object or event. When we experience a visual illusion, we may see something that is not there, or fail to see something that is there, or even see something different from what is there. Because of this disconnect between perception and reality, visual illusions demonstrate the ways in which the brain can fail to recreate the physical world. By studying these failings, we can learn about the computational methods used by the brain to construct visual experience.
In the accompanying slide show, we will showcase several basic categories of visual illusions and what they can teach us about the brain.
View a slide show of illusions
Mind Matters is edited by Jonah Lehrer, the science writer behind the blog The Frontal Cortex and the book Proust was a Neuroscientist.
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13 Comments
Add CommentIllusionism and perception have always played a very important role in ethe visual arts, from Classical Greece (with the Parthenon) to the present.. with the movies. IRENEALHANATI
Reply | Report Abuse | Link to thisFor starters, one thing that has scratched my brain since I was about 10 is that, if it is a certainty that our perception isn't an accurate representation of reality (beyond the veil of maya), how do we know that the instruments we use to interpret information outside of our perceptive range are themselves interpreting "true" reality; are we blind-folk poking an elephant with a stick and calling it a wall?
Reply | Report Abuse | Link to thisSecondly, with regards to the slides, a similar one to slide 4 can be seen at http://visualfunhouse.com/hidden_images/lady-in-the-tree-optical-illusion.html
Reply | Report Abuse | Link to thisFrom what I'm told, most children don't see the naked woman.
& slide 3 I find Similar to the feeling you get when youre on a stationary train and the one next to you sets off; I usually experience the whole physical lunge effect as if it's the train I'm sat on that is setting off.
Another simple mental illusion Ive found is lying or sitting in a familiar room with your eyes closed, then convincing yourself that youre laid/sat the other way round; when Ive done this Ive actually felt the dimensions of the room change to fit my perception; then get a mild feeling of nausia when I open my eyes and the room's the wrong way round!
+1 final illusion; when you stare at a ceiling fan and relax your eyes (in the right kind of way), it appears to speed up, before switching into reverse... doesn't do your eyes much good tho'
Ambiguous figures:
Reply | Report Abuse | Link to this"You can see one of two possible images, but never both of them at the same time."
Uh yes I can. It's pretty easy actually.
That's true... we don't see all the invisible aliens running around here.
Reply | Report Abuse | Link to thisAs an invisible alien I object to wishywish talking about me as if I'm not here!
Reply | Report Abuse | Link to thisAlso, what is up with your advertisers trying to download malware onto my machine lately? I mean really, don't you vet this junk before putting your site endorsement on it?
In the SHAPE DISTORTION ILLUSION (2/5) If you tilt your head to the sides all those square wont be distorted anymore
Reply | Report Abuse | Link to thiscool
Reply | Report Abuse | Link to thiscool
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Reply | Report Abuse | Link to thisEye Illusions are awesome
Reply | Report Abuse | Link to this<a href="http://www.google.com">Cool indeed!</a>
Reply | Report Abuse | Link to thisvar link = $(this).html();
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