<p>I can't tell you the exact underlying mechanism unfortunately. I can analyze the illusion so as to approximate an answer.</p>

<p>You can see that the effect is virtually absent when the white squares on the two rows are nearly similarly sized (rook - pawn). The effect is biggest when the white surfaces are most unequal (king - pawn). </p>

<p>Additionally, to me, the white fields seem to be bigger than the black ones, not so much the reverse. I think it is the illusion of the remainder of the black fields looking like they are offset and widening, which is most evident in pawn - bishop.</p>

<p>So in all, the white squares are central to the illusion, and the black fields are seemingly bordering the white fields. It now looks as if the black outlines are widened around the white squares. This may be related the fact that the white squares seem to be interpreted as squares and the black field (-remainders) as the borders of the white squares. In other words, the white fields are interpreted as squares, the black fields as borders.   </p>

<p>Hence, I think this illusion is to be sought higher up in the cortex, where visual images are interpreted as opposed to 'simple' retinal illusions. </p>

CC BY-SA 3.0
2015-03-29T14:01:49.847Z
2015-03-29T14:01:49.847Z
AliceD
<p>As I was working on a basic chess application for Android, I loaded some chess clip art into my imageviews. Then this happened. Look closely at the top two rows.</p>

<p><img src="https://i.sstatic.net/oCkQp.png" alt="The Illusion"></p>

<p>At first I was startled. My imageviews had reformatted themselves! But no. All the squares are still identically sized. </p>

<p>Question is this: How does this image fool our minds? What can illusions like this tell us about how the brain is wired?</p>

<perception><cognitive-neuroscience><vision><consciousness>
How does this illusion - that I just inadvertently created - work?
zlaporta
# How does this illusion - that I just inadvertently created - work?

(Asked by: username_0 on 2015-02-13)

As I was working on a basic chess application for Android, I loaded some chess clip art into my imageviews. Then this happened. Look closely at the top two rows.

![The Illusion](https://i.sstatic.net/oCkQp.png)

At first I was startled. My imageviews had reformatted themselves! But no. All the squares are still identically sized.

Question is this: How does this image fool our minds? What can illusions like this tell us about how the brain is wired?

**Tags:** perception, cognitive-neuroscience, vision, consciousness


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## 1 answers

### Answer by username_1 on 2015-03-29. Score: 1

I can't tell you the exact underlying mechanism unfortunately. I can analyze the illusion so as to approximate an answer.

You can see that the effect is virtually absent when the white squares on the two rows are nearly similarly sized (rook - pawn). The effect is biggest when the white surfaces are most unequal (king - pawn).

Additionally, to me, the white fields seem to be bigger than the black ones, not so much the reverse. I think it is the illusion of the remainder of the black fields looking like they are offset and widening, which is most evident in pawn - bishop.

So in all, the white squares are central to the illusion, and the black fields are seemingly bordering the white fields. It now looks as if the black outlines are widened around the white squares. This may be related the fact that the white squares seem to be interpreted as squares and the black field (-remainders) as the borders of the white squares. In other words, the white fields are interpreted as squares, the black fields as borders.

Hence, I think this illusion is to be sought higher up in the cortex, where visual images are interpreted as opposed to 'simple' retinal illusions.


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