The Coffer illusion

August 11, 2017 • 3:52 pm

Okay, look at the photo of the door below. Time yourself from the start to see how long it takes you to find the circles.

How many circles do you see? Do you see any?

There are sixteen circles. Do you see them? If you don’t, and for an explanation, go to the next page by clicking “read more”

Here’s a reveal: one circle. The rest should now be obvious.

This is the “Coffer Illusion, explained like this:

This fascinating image was created by Anthony Norcia of The Infant Vision Laboratory at Smith-Kettlewell. It is referred to as the Coffer Illusion due to its close resemblance to the 3-dimensional coffers usually found on wooden doors (a coffer is a decorative sunken panel). Dr. Norcia claims that the illusion works because segmentation cues are pitted against the observer’s strong conviction to interpret the image as a series of rectangular coffers with closed boundaries.

When Dr. Norcia tested this illusion on a group of 100 people, the average time taken to see the circles was 45 seconds. A few individuals were able to spot the hidden shapes after only 10-15 seconds, while other persons took much longer and/or required explicit hints to finally see the circles. How long did you take?

I didn’t time myself, but it took me a while.

 

87 thoughts on “The Coffer illusion

  1. It took only 2 or 3 seconds to see circles but only on the rightmost column. My right eye is a bit bleary, which might have contributed. Then I could see the others but it took effort. I am not convinced I can see all 16 at once!

      1. Same here. Right one first then the left one, then the second to left (more difficult), and still very hard to see the one in the second to right column, despite knowing where to look and focus.

          1. “I wonder what’s different about that one column?”

            The structures inside the circles or rectangles in the first and fourth columns are symmetrical, while those in the structures in the second and third column are not. We spot this symmetry first, which leads us to look for further symmetries (unconsciously). The prediction of things by our brain is one of the fundamental mechanisms in perception, we see first what we expect to see (and this is why it is difficult to spot the hidden lizard or snake in “spot the lizard” images because we look for obvious details, like ears or tails, which then are hidden). We enjoy classical music because we hear what we expect and know, and this is the reason that you have to listen to a classical piece a few times before to enjoy it fully).

  2. Same with me, just two seconds or less to see the rightmost ones, but could not see the leftmost ones. But if you scroll the image while looking, all are obvious.

    1. Same here. Once I saw one example, all the rest jumped out. It seemed too easy. I was expecting something like “32 circles”, and that I would need to go hunting. I’m usually slow at things like this.

  3. Pretty quick to see 4, then 7, then 10, then 14 of them, but never could see the middle 2 in the 2nd column from the right.

  4. 16 – first in about 2-3 seconds, then the rest within 2 more seconds. No cue.

    Fabulous illusion!

  5. I looked at the image before I read the prose for a few seconds. Didn’t see any circles. Then I read the prose and looked at the image again. I saw the circles within seconds.

  6. A few days ago, when I first saw this illusion, I didn’t see the circles and quickly gave up. This time, I saw the circles from right to left almost instantaneously. I’ve never been very quick on these kinds of puzzles, for whatever reason.

    1. Same here; can’t remember where I first saw it, though, can you?

      I didn’t spend much time on it then; this time it jumped out at me before I even began to read the text.

    2. Similarly here too. I saw it a day or two ago on Twitter – and on a different screen, which displayed it in a vertically-squeezed form. I couldn’t see the circles at all. In landscape format on the laptop – and presumably without the scaling function my phone used on Twitter, it took about 30 seconds to see the circles. As others say up-thread, the ones on the right appeared first, spreading left.

  7. I’ve noticed that a huge(covfefe) number of commenters admit to being miraculously good at this puzzle, but few are willing to append a shameful confession of abject failure. I’m detecting a small selection bias. 😉

    1. Ironically, to claim that you ‘detected’ selection bias, sounds like selection bias to me too: you ASSUME selection bias, because that seems to be a plausible explanation for your observation, but unless you actually test for it, you can’t state that you ‘detected’ it: it’s technically possible that everyone spoke the truth.
      😉

      1. I’m sure everyone spoke the truth. After all this is WEIT. But, self selection occurs too. Those who succeed comment. Those who don’t succeed crumble in dismay and fear to admit failure. Am I alone it this shame? 😎

    2. I admit to abject failure. I’ll pass on shameful, though. (I’m consistently awful at optical illusions.)

          1. The glass is about 2/3 full. It has big, chewy, tannins, is quite dense and complex.
            One might even say bold. It’s a mild domestic burgundy without any breeding, but I’m sure you’ll be amused by it’s presumptions.

  8. Took me ages to find the circles but the main point is why is this different for different people. Coming up with amusing optical illusions is fun but where is the science?

  9. Maybe one second, maybe two – but interestingly (it may have only been a coincidence) it was scanning down and seeing the sentence “there are sixteen circles” that did it. I looked up and saw them immediately. I didn’t see them in the second while I wasn’t sure if they were really there.

        1. After about 30 seconds, looking at the sixteen focussed me, too.
          Only then I saw 5×5.
          Probably because I’m still kind of drunk.

  10. I have seen this illusion before. Staring at the X in the center makes the circles pop out quickly. The circles with the most dark bars pop out easier than the others.

  11. I saw all sixteen straight off. That is, I recognised one (top right) straight away and instinctively deduced that all the other junctions of lines should be circles and when I looked, there they were. They seem so obvious, I can’t understand how anybody could miss them. I do agree the second-to-right column is the least obvious, due to the lower contrast between the vertical and horizontal lines.

    I *was* ‘primed’ to look for circles by having read the text of this post in my email before I called up this web page. And also I was expecting some sort of visual illusion. So maybe without that ‘priming’ it would have taken me longer to notice.

    cr

    1. I think priming is important here. I had noticed the right hand column of circles before I had finished reading the first sentence. Looked straight at the central x, and defocused. All 16 circles leapt into view. time spent looking directly at the image was probably less than a second. If I wasn’t primed I don’t know how long it would have taken, or if I would have noticed the circles at all.

  12. Probably about 10-15 seconds, starting on the right column. Doubt I would have seen them if not primed and they still don’t jump out at me.

  13. I lookly quickly at the first image, did not see the circles, and then looked at the second image with the red circle. I still did not see the circles but when I looked at the first image again more closely I saw the circles on the right side and after that I could see all of the,

  14. I saw the top left-hand circle almost immediately, and all of the others clicked into place like a reverberation wave across water. My eyes (not as good as they used to be, with quite a few ‘floaters’ now) seem to be able to turn them on and off at will. Interesting.
    (I’ve just allowed myself a written single-adjective sentence for the first time in my life; I wonder [not really!] where that comes from …)

  15. I had a look at it yesterday, but gave up when I couldn’t spot any. I came back to it today and saw the first one, in the right hand column instantly, and after a couple of seconds, saw the others. Perhaps my mind was subconsciously working on it between visits.

  16. ~30sec. I was thrown off by the fused, vaguely circular appearance of the third column. When I decided that wasn’t it, I guess I started looking at the center of the coffers. Nada. But looking at the bars between the coffers they’re instantly visible.

  17. It only took a second or two to see the circles — the first time. After that, though, I couldn’t make them pop out at me. I think I was so eager to see them that my eye wouldn’t stop wandering. Finally I gave up. I looked directly at where one of the circles would be. There it was. The others appeared. As long as I’d look where they should be, they’d be there. As soon as I looked at the X again or the squares, they’d be gone.

  18. It took about ten seconds for me to see the four circles in the right-hand column. As for the other circles, I got glimpses of them in my peripheral vision, but when I looked directly at them, they disappeared.

  19. Took me a while, a dozen seconds or so. Didn’t really time it. I wonder if I would have seen any if there had not been the question about how many circles one could see.
    For the best visual and optical illusion site go to http://www.michaelbach.de/ot/
    . I think he works at Tubingen University

  20. I can see another dozen or thereabouts.

    Firstly I noted the sixteen referred to all bisected horizontally by the ‘panel lines’.

    I reasoned that the same illusion might also apply around the vertical panel lines. Sure enough, with patience, they can be seen too, only slightly less defined than the obvious sixteen that are horizontally bisected.

    1. Yes! I didn’t see that at first. But they remain somewhat ‘cut’ in the middle, and sometimes segue into a vertical sinusoid.

  21. I tried looking at it on my phone without seeing any circles, but when I used my laptop I saw all 16 in 45 seconds. Now I can’t not see them. My wife saw them in 5 seconds, but that’s no surprise since she does everything better than I do.

  22. As a painter of —
    Architecture, I’m seeing,
    Immediately,
    All of the circles, and then?
    Went to “looking”, and “tooking”.

          1. In geberal I don’t like the fiction as well as I used to, but the cartoons are still great!

          2. George Booth’s still alive (at 91) and this cartoon was in the most recent issue! ( I’m actually caught up on my NYers.)

  23. It took me a while to spot them – longer than reported by most others – especially the third column. But when I took those so-called intelligence tests, that often included spacial recognition problems, I usually did quite good – like 99+ percentile good. But it was about 50 years ago that I took those tests – maybe I have deteriorated a bit since then.

  24. I saw them immediately, before reading the text, and I was surprised that most people have to look for them.
    I thought the illusion might refer to the nine larger circles, which I see at the intersections of groups of four circles. But the explanation makes no mention of that.
    The third column is decidedly less prominent than the other columns.

  25. I saw them fairly quickly (a few seconds) but what was weird was that I saw the ones down the rightmost column more quickly, and still see them more easily. They seem to “pop out” and stay that way, while the other ones blink in and out.

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