Therefore, with a 10-minute experiment, we have shown the existence of neurons in the brain that require the joint presence of a specific color and orientation to fire. The adaptation effects that result from fatiguing them are called contingent aftereffects. The McCollough effect is an orientation-contingent color aftereffect.
A peculiar aspect of the McCollough effect is that once it has been generated in your brain, it can survive for a long period. Look again next week, and the stripes may very well continue to look red- or green-tinged. (The strength of the aftereffect normally ebbs gradually over time, unless you are submerged in darkness, in which case it endures undiminished!) It has therefore been suggested that contingent aftereffects have more in common with memory and learning than with purely visual adaptation. It is as though during the initial adaptation (or exposure) phase, the brain were saying, “Every time I see horizontal stripes, there’s too much red in the world, so let’s pay less attention to red. Whereas every time I see vertical stripes, I see too much green. So let me damp down the green when I am shown vertical white stripes and damp down red when I see horizontal white.” (In the same way, your brain says, “Any time I set foot into the hot tub, it’s hot, so let me recalibrate my temperature judgment accordingly. I’ll expect it to be hot and won’t withdraw my foot in surprise.”)
It has been shown that certain drugs (including caffeine) can enhance the persistence of the McCollough effect. The phenomenon deserves further study as a way of approaching the neurochemistry of perceptual mechanisms. Visual aftereffects may thus give us insights not only into the neural channels that mediate perception but also into the neural—and possibly pharmacological—basis of memory and learning.
This article was originally published with the title Aristotle's Error.
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Reply | Report Abuse | Link to thisVery interesting experiments indeed. It would help a lot to have the corresponding images though... Where are they?
Reply | Report Abuse | Link to thisHow do you know how many teeth Mrs Aristotle had? Aristotle does not differ from today's scientists in accepting data from other researchers, in not having enough time to check everything by his own experiment, nor in concentrating his efforts in only one of theory vs experiment.
Reply | Report Abuse | Link to thisBut Aristotle did have a stronger sense of logic and creativity and insight than most of the people in science today. He is remarkable in having produced work that passed later researchers' empirical and theoretical trials for millennia. It will be interesting to see what ideas from today come to be so far reaching in scientific thought for millennia to come.
the lack of pictures probably raises the average customer's frustration level. management probably hopes this will raise the occurrence of paying customers.
Reply | Report Abuse | Link to this"Curiously enough, much of the current scientific understanding of that process is based on the study of visual illusions."
Reply | Report Abuse | Link to thisWhy should this be "curious" sight and hearing are certainly the most 'available' of the 6 senses,(the sixth being consciousness).
When anyone thinks he has identified a mistake made by one of the philosophers, we are often quite interested in examining the text. Sometimes a mistake is just a mistake, I imagine, but such cases are the least interesting. On careful consideration, some apparent mistakes come to seem deliberate and revealing. Others dissolve upon reinterpretation. I'm delighted you had recourse to Aristotle's texts when writing your article. When you write about him in the future, please include mention of the name of the work and cite the passage. Some of your readers will love you all the more.
Reply | Report Abuse | Link to thisScientific American's error...
Reply | Report Abuse | Link to this"The eye has three receptor pigmentsfor red, green and blueeach of which is optimally (but not exclusively) excited by one wavelength."
Sorry, but the color receptors in the retina do not correspond to the classic additive primary colors of red, green and blue. The three distinct cone cell types (S, M and L) responsible for color perception respond to chromatic light with peaks in violet, green and yellow-orange. For reference:
http://en.wikipedia.org/wiki/File:Cone-fundamentals-with-srgb-spectrum.png
Will you Please clear up the question between (l). blue, green and red Vs (2). violet, green and yellow-orange? ?
Reply | Report Abuse | Link to thisIt seems quite remarkable to me, in the implicatons, and the apparent color combinations of the second.
Waiting.
Hypodontia (having fewer teeth) occurs in about a quarter to a third of Caucasians. One fifth of them are men; four fifths are women. Hyperdontia (having extra teeth) is in contrast very rare among Caucasians. Is it not the case, then, that Caucasian women have, on average, fewer teeth than Caucasian men? I guess that the authors didn't bother to count, which leads me to wonder what other facts they fabricate in the guise of science.
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