McCullough Effect

OK. This has absolutely nothing to do with communism or space whatsoever. But this blog is my blog. I can post whatever the hell I want to if I deem it interesting. Because I can’t really foster a blog with occasional posts about space and communism, I’m going to post other cool science things too.

Today I’m going to talk about something I just learned about. Something called the McCullough Effect. Now I must tell you. While the effect is pretty much harmless, it will seriously fuck with your vision for months. Sort of. Only if you look at black and white stripes, which, unless you have an unconventional wardrobe, is usually only really seen in bar-codes. So I must warn you. DO NOT ATTEMPT TO LOOK AT THE FOLLOWING IMAGES FOR MORE THAN FIVE MINUTES UNLESS YOU’RE FINE WITH SEEING COLOR WHERE THERE IS NONE FOR MONTHS TO A YEAR.

Also it doesn’t work if you’re colorblind. Not with the colors I’ve chosen. You can choose any two high contrast colors though.

Apart from that, it’s pretty harmless. The only harm that comes from it is that it’s an afterimage that lasts three months.

OK. First take a look at this image.

McCollough Effect

What do you see? Chances are, you see two boxes of horizontal black-and-white stripes, and two boxes of vertical black-and-white stripes. We’re going to revisit this picture later.

Now I’m going to insert some high contrast stripes.


Green and black horizontal stripes. Simple enough, right?


Red and black vertical stripes. Nothing surprising here.

Now what I want you to do is look at the top picture. Count sixty seconds out. It doesn’t have to be exact. Just roughly one minute. Then look at the bottom picture and do the same. Then look at the top one again. Then look at the bottom one. So you should have stared at both images for a total of about four to five minutes.

Now look at the top picture again. Does it look any different? I’m not going to tell you what you’re supposed to see. But it’ll be similar to an afterimage–only more intense, and it doesn’t make sense. If you have a device with a screen you can turn without auto-rotate, then turn your screen and watch things shift in front of your eyes. If things don’t look wonky, do it for another five minutes. It took me half an hour of total exposure time for me to see anything incredibly perceptible and undeniable, so maybe you might actually need 15 minutes to see it. But you don’t have that sort of attention span, do you…

I found a Flash version of this, so if you have a Flash-compatible device, you can have this time and flash automatically for you. Again. I highly advise against staring at it for more than 5 minutes, but honestly, I found the effect most perceptible after 15 minutes, and incredibly perceptible and undeniable after an hour of exposure.

Note that in exposing myself to minimum one hour (I can’t stop looking at this, for some reason) means that the effect is pretty much guaranteed to last me over a year.

I can tell you that I was skeptical at first–there’s no way that this could last three months. There’s no way this could last even 15 seconds. But I found that 1 hour of exposure led to 1 hour of intense visualization, and diminishing (but noticeable) effect for at least a day afterwards.

I’m going to attempt to expose myself for at least 15 minutes every day for the next week or so. I’m going to see if I can harden a strong visualization that lasts three months. Will it seriously fuck with my vision? Very likely. Not by much, but I’m probably going to develop a hatred of stripes. Or love. I designed a dress based off of the McCullough effect that can both test and trigger the effect, as well as get people to stare at my medium-endowed chest for five minutes. I might actually attempt to make it in the future.

Sure doing this may permanently condition me to see color in black and white stripes for the rest of my life. But anything that sounds stupid–but isn’t truly harmful–can be justified by preceding it with “for science!” And that’s what I’m doing right now.

The interesting thing about this effect is that unlike an afterimage (depicted below),


it doesn’t operate on the retinal level, and it isn’t fleeting. It operates on a cognitive level. If I understand it correctly, the same plasticity effect is what allows you to be able to get used to something insanely different (for instance, goggles that mirror your vision) given enough time. And once that stimulus is removed, the “real world” appears to be wonky to you. The thing is, what I’m surprised about, is that usually such only takes about a day or so to readjust, and hours to days of exposure/induction. Yet in this case, you can achieve induction in as short of a time span as five minutes, and have the effect last for days. A fifteen minute exposure lasts for months, and I’ve heard instances where it lasted for years in some people. The effect diminishes over time, but come back to this post tomorrow and look at the black and white image. It’s likely still tinged in color. Come back a week later. Very faintly, likely, it’s tinged. It’s mind-blowing how long this one lasts.

Also the text editor is black on white. The text is surrounded by a reddish haze. If I hold my laptop sideways, the text is surrounded by a greenish haze. It is SO WEIRD.
If you want to know more.

It is now my new favorite optical illusion, and I really wonder what this specific illusion says about cognitive psychology. How we can see colors from nothing. And if you think this is just a screen illusion, print out the black and white bars, or even draw them out with a sharpie or something on white paper. It’s so legit.

I had to put some effort in finding a non-tinged version of the black and white bars, since it was hard to tell which picture is a “this is what you’re supposed to see” image and the original image when I’m already exposed since they all look the same to me now.


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