The Cage Triple Illusion

Today I present you Peter Baker’s work. Open the image full size to see the effect better. This is description Peter provided: “Hi there! Here’s an illusion I created a year or two back, playing with equiluminance to generate a false sense of motion, and foreground background reversal. (And maximising attention by diagonalising the grid.)

I understand the false motion, and the foreground/background flipping, up to a point… but I’m puzzled about an unintended third effect: the zebra worms don’t look straight edged – they seem to be lumpy. Any ideas? And there’s a fourth effect – the edges of the worms seem to be brighter…

As for the title… why ‘The Cage’? On the surface we seem to be caged by either neon tubes (and more distant black and white bars) – or by the zebra worms. But really, we are caged by the fiction our own sensory apparatus presents to us as reality.” Did I mention the 5th effect? This picture really makes you nervous!

23 Replies to “The Cage Triple Illusion”

  1. Hi mj – yes, about a year or so ago. I was working on an illusions project, and saw some good ones using equiluminescence* to create a motion illusion in ‘The Fantastic World of Optical Illusions’ by Al Seckel, and decided to experiment myself. I work a lot in Photoshop, so it was fun!

    *This is where, if you change the colour to greyscale, the boundary disappears, because they are both exactly the same tone of grey. This is where the interesting bit starts, because the brain cannot see shape in colour, only in black and white (and grey, of course). So the part of the brain that analyses colour knows that the neon tubes are blue and violet, but the part that analyses where things are can’t see a damn thing, and the two parts of your brain get into a tizz about which one is right. Generally when this happens though – and you can see the colour of the thing, but not where it starts and finishes, it’s because it’s moving. So (my speculation now) one of them pushes the ‘movement’ button to cover up the disagreement. So you see a vague sort of movement, without seeing just what is moving – a bit like when you look out of the window and think you see very fine drizzle, but can’t be sure, just have a sense of something moving.

    And diagonals work because the brain is programmed to respond to them. In nature it generally means that something is accelerating, decellerating, falling over, or changing direction – and your eye has to automatically spot anything like that, because it may well mean something is soon going to be food. If it’s leaning over because it’s changing direction, it may be you. Strong evolutionary pressure for such a trigger to emerge in the brain.

  2. mj didnt u read the top???
    Peter provided: “Hi there! Here’s an illusion I created a year or two back


  3. I don’t get a false sense of motion (maybe my monitor’s settings aren’t right? I have mine at a lower contrast than most other people) but it looks a bit like stairs to me – only I can’t tell if the purple or the stripes are the actual steps.

  4. I see nothing wrong with the “zebra worms”. All I can see is the Violet lines running up and down with Blue and Red, but I am heavily Dyslexic if this has something to do with how I view the image?

  5. hahahaaaah i thought at first “there trying to make it look like hes walking upstairs but im not stupid hes just laying on the floor!!”
    well i guess i am stupid :)

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