A Great Visual Illusion: Radiating the Same Luminance

This is a great visual illusion.

The top and bottom chess pieces radiate the same luminance. (I did some sampling to check, and it seems to check out.)

(Tip of the cap to Luiz Pessoa.)

The Donkey Kong Visual Illusion

This visual illusion ought to be called the "Donkey Kong Illusion"

Horizontally aligned rows appear to tilt alternately. pic.twitter.com/80pfmXPql6

— Akiyoshi Kitaoka (@AkiyoshiKitaoka) January 9, 2022

A Visual Illusion: Game-and-Watch Style

Here is a visual illusion (in game-and-watch style) for you. The illusion is of the forward motion. It arises from a border of about 1 pixel that lags/leads the dominant color.

This may be the strongest optical illusion I’ve ever seen.pic.twitter.com/J8fCqbQUJ1

— Siqi Chen (@blader) November 22, 2020

(Tip of the cap to Sydney Padua.)

"Rotating" Cubes: An Impressive Visual Illusion

This visual illusion is very impressive. (I was skeptical and stopped and restarted the animated gif many times to look at the angles.)

One of the most powerful motion illusions I've seen: The cubes appear to be rotating in opposite directions – but they're not actually moving at all… 😮

Credit: @jagarikin pic.twitter.com/RgUFskZbZU

— Steve Stewart-Williams (@SteveStuWill) August 15, 2020

(Tip of the cap to Philip E. Tetlock.)

A Colorful Visual Illusion

All the balls are the same color — and that color is *brown*! pic.twitter.com/JriPXHnNYR

— Chaz Firestone (@chazfirestone) June 14, 2019

(Tip of the cap to Lucas Lacasa.)

Visual Illusion: Starry Night Edition

Very cool!

Stare at the white dot for 10 seconds, then look at Van Gogh's Starry Night below. pic.twitter.com/GDECuOrdau

— Universal-Sci (@universal_sci) March 27, 2019

A Funky Visual Illusion: What's the Frequency?

From my own experimentation, the frequency matters.

You can only see this optical illusion if you shake your head (I’m serious) 😂 pic.twitter.com/WhtZ1b0r4t

— Dr Michelle Dickinson (@medickinson) January 10, 2019

(Tip of the cap to Jenna Walrath.)

A Really Fancy Visual Illusion

Wow!

Amazing motion illusion.
V5 is firing due to V4 saturation! pic.twitter.com/oNgxRXXN3f

— Alice Proverbio (@AliceProverbio) October 12, 2018

Amazing Visual Illusion: A Dynamic Müller–Lyer Illusion

This visual illusion is amazing. It is a dynamic Müller–Lyer illusion.

This is probably the best illusion I've ever seen. The blue and red lines are all the same length; none is moving or changing size, and they’re all at the same level. Only the arrowheads are moving. https://t.co/bDyeOKXgbC pic.twitter.com/V6KrmLkiPr

— Steve Stewart-Williams (@SteveStuWill) October 4, 2018

(Tip of the cap to Marcel Salathe.)

A Bulging Visual Illusion

This is a great visual illusion!

The image appears to bulge out, though it consists of squares aligned vertically and horizontally. pic.twitter.com/uwb0HJPyiw

— Akiyoshi Kitaoka (@AkiyoshiKitaoka) June 20, 2018

(Tip of the cap to Ben Orlin.)

Visual Illusion: Snakes on a Plane

Enough is enough. I've had it with these ****** illusory snakes on this ******-****** plane.

Snakes appear to move. pic.twitter.com/HggajNQsHY

— Akiyoshi Kitaoka (@AkiyoshiKitaoka) March 17, 2018

(Tip of the cap to Maggie Koerth-Baker.)

Curvature Blindness Illusion

This is amazing!

The Remarkable 'Curvature Blindness' Illusion - Neuroskeptic https://t.co/KDPouUSuOW pic.twitter.com/AEHIdW9j3P

— Sabine Hossenfelder (@skdh) December 8, 2017

Another Cool Visual Illusion

Just a reminder that reality happens in the mind. pic.twitter.com/svqAl4xjze

— Science (@scienmag) August 27, 2017

(Tip of the cap to Justin Lanier.)

Another Optical Illusion: How Many Circles Can You Find?

Here's another optical illusion. It's not as visually striking as the other one I posted recently, but it's interesting (and, unlike the other one, the basic qualitative feature of the illusion is not one that I have not encountered before).

In this image there are 16 circles. Don't you find them? Look again carefully & discover the 'coffer illusion' https://t.co/zPpephKSos pic.twitter.com/fnzOFI83GP

— Massimo (@Rainmaker1973) August 9, 2017

Awesome Optical Illusion: Bathroom Tile Edition

Versions of this optical illusion (much less elaborate variants of it) appear to be ubiquitous in restaurant bathroom tiles. :)

Terrific optical illusion by Victoria Skye. @RichardWiseman @chriscfrench pic.twitter.com/IeSFupAcfU

— Martin S Taylor (@martinstaylor) August 7, 2017

Ambiguous Cylinder Illusion

The ambiguous cylinder illusion is funky.

Awesome Visual Illusion

This visual illusion is really cool!

Note: I originally referred to this illusion as an "optical illusion", but my friend Steve Van Hooser, a visual neuroscientist, has pointed out my use of the incorrect term: "I know you are a stickler for details, and as a visual neuroscientist I feel you'd want to know: say "visual illusion" rather than "optical illusion". Because the visual system produces this illusion. There are true "optical" illusions, like the illusion of water on a hot road ahead. That is an optical illusion because it is the diffraction of light that causes the illusion." (I have made this same error on several prior blog posts, which I may eventually look up and correct.)

Motion Sickness from an Optical Illusion in a Seminar

The talk that is just finishing in the neural rhythms and oscillations workshop concerns optical illusions. The speaker walked us through and demonstrated the "flickering pinwheel illusion" in his slide. It's a very interesting phenomenon, but unfortunately that slide has also very seriously kicked in my motion sickness. Sigh... I feel sick.

And then later on in the talk, the speaker was connecting this stuff to illusions in things like stroboscopic lights, drugs, and migraines. As some of you know, the latter of these is extremely familiar to me from my own experiences --- and stroboscopic lights have triggered them on occasion (and I specifically try to avoid stroboscopic lights). Sigh. Well, at least I have provided another data point.

I guess some neuroscience talks ought to include motion-sickness alerts along with them? I really hope this doesn't mess me up for the rest of the day.

This also reminds me of Kramer's epilectic reaction to Mary Hart on Seinfeld. Just imagine that seen from Seinfeld, except with people at a conference watching a talk on optical illusions and me in the background playing the part of Kramer.

Update: It turns out that another audience member (who also has a history of migraines) who knew better purposely covered her eyes during that slide. I didn't know that such illusions could cause such things, so if I had possessed the scientific knowledge beforehand, I could have done something about it. Burned by my lack of knowledge!

Optical Illusion of the Day

You might remember that I posted a link a while back to this awesome optical illusion of a spinning silhouette. (I can't find my blog entry on it at the moment, so I must not have tagged it very well.) Here is a more generic but still cool optical illusion that I mentioned previously.


Well, here is another really awesome optical illusion, which was posted on Bad Astronomy. Damn! It's probably not as cool as the silhouette, but I still really like it. It also makes me thing of the green/blue paradox (or whatever that's officially called). :)

Also, here is an aural illusion that I can't get to work. I get exactly the same thing whether or not my eyes are open or closed. Can somebody explain this one to me?

(Tip of the cap to Rob Neyer.)

Optical illusion of the day

Take a look here for the optical illusion of the day.

I've, of course, encountered this particular type of illusion many times, but I think it's just fantastic for it to occupy the entire facade of a building.

(I found this image on the MAA website.)