How the brain's architecture makes our view of the world unique

December 5, 2010
The Ebbinghaus illusion. Most people will see the first circle as smaller than the second one Researchers found a strong link between the surface area of the primary visual cortex and the extent to which volunteers perceived the size illusion -- the smaller the area, the more pronounced the visual illusion. Credit: Dr Samuel Schwarzkopf, UCL

( -- Wellcome Trust scientists have shown for the first time that exactly how we see our environment depends on the size of the visual part of our brain.

We are all familiar with the idea that our thoughts and emotions differ from one person to another, but most people assume that how we perceive the visual world is usually very similar from person to person. However, the primary visual cortex – the area at the back of the responsible for processing what we see in the world around us – is known to differ in size by up to three times from one individual to the next.

Now, researchers at the Wellcome Trust Centre for Neuroimaging at UCL (University College London) have shown for the first time that the size of this area affects how we perceive our environment. Their study is published online today in the journal Nature Neuroscience.

Dr D Samuel Schwarzkopf, Chen Song and Professor Geraint Rees showed a series of optical illusions to thirty healthy volunteers. These included the Ebbinghaus , a well-known illusion in which two circles of the same size are each surrounded by circular 'petals'; one of the circles is surrounded by larger petals, the other by smaller petals. Most people will see the first circle as smaller than the second one

In a second optical illusion, the Ponzo illusion, the volunteers were shown two identically sized circles superimposed onto the image of a tunnel. In this illusion, the circle placed further back in the tunnel appears larger than that placed near the front.

By adapting these illusions, the researchers were able to show that individual volunteers saw the illusions differently. For example, some people saw a big (although illusory) difference in size between the two circles, but others barely saw any difference in apparent size.

Using functional magnetic resonance imaging (fMRI), the researchers were also able to measure the surface area of the in each volunteer. They found a great deal of variability in the size of this area. Surprisingly, there was a strong link between its size and the extent to which volunteers perceived the size illusion – the smaller the area, the more pronounced the visual illusion.

"Our work is the first to show that the size of part of a person's brain can predict how they perceive their visual environment," explains Dr Schwarzkopf.

"Optical illusions mystify and inspire our imagination, but in truth they show us that how we see the world is not necessarily physically accurate, but rather depends a lot on our brains. Illusions such as the ones we used influence how big something looks; that is, they can trick us into believing that two identical objects have different sizes.

"We have shown that precisely how big something appears to you depends on the size of a brain area that is necessary for vision. How much your brain tricks you depends on how much 'real estate' your brain has put aside for visual processing."

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Dec 05, 2010
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5 / 5 (3) Dec 05, 2010
Well someone is a tad bitter today.
2 / 5 (3) Dec 05, 2010
I think it's FASCINATING STUFF! I love how Basic Learning is being revealed more & more! It's a Sure way towards removing barriers in education. I LOVE YOU SMART SCIENCE PEOPLE!
btw, any videos would be WONDERFUL. I Love your stuff. =))
3.7 / 5 (3) Dec 05, 2010
^I'm a smart science person...203-470-8759
4.5 / 5 (2) Dec 05, 2010
very interesting.

this seems a reliable indicator to estimate a brain architecture feature. You could do this test on line.

Next, I would like to know what else is co-related with this type of brain architecture. Is there a higher color sensitivity? As a practical question, in graphic design it is often required to visually judge the appropriate amount of white space around a logo or the appropriate amount of white space between lines of text so that they are easiest to read. Page margins in particular exhibit a similar pattern of some people finding them essential to look at the page information while others find them only a waste of paper that adds nothing to their reading or viewing experience.
5 / 5 (2) Dec 05, 2010
Just another form of intelligence, good article and it just goes to show you, we are all different.
If I'm not mistaken, I think this is called spatial-temporal reasoning. Some people do better at certain maths than others such as geometry and algebra for instance. This could definitely have something to do with that.
5 / 5 (1) Dec 06, 2010
who the fuck cares

Well, perhaps, you should. The shallowness of thought and limited vocabulary are signs that parts of your brain may have been affected.
3 / 5 (3) Dec 06, 2010
Unfortunately this type of studies have a lot of error potential. 1. A dedicated piano player has certain parts of motor cortex enlarged. 2. The mere measurement of any cortex area is difficult. Where are the limits? 3. Does some occupations/hobbies (ornithology whatever) increase the optical cortex? 4. "Natural" variation of optical cortex/rest of cortex ratio. 5. Absolute cortex size related to body weight, female/male etc. 6. Only 30 participants ... Interesting that optical illusions are seen different by different persons (old knowledge) BUT ... "Our work is the first to show that the size of part of a person's brain can predict how they perceive their visual environment," explains Dr Schwarzkopf ... Dr Blackhead is hyping way too much ... don't make science into a "fast sales product" please !!!
1 / 5 (1) Dec 06, 2010
Mitigating factors for Mr Schwartzkopf is the fact it is hard (competition) to get funds for research and publishing much and fast and especially to "gold standard" Nature is key ... but balance is needed.
5 / 5 (2) Dec 06, 2010
We've seen optical illusion analysis before, but what is new to me is that visual cortex size between people can differ by a factor of 3? That's HUGE. I'd like to see the evidence. Maybe I'm a lizard and don't know it.
not rated yet Dec 06, 2010
who the fuck cares

Just keep telling yourself: "It's not size that matters, it's how you use it"
1 / 5 (1) Dec 08, 2010
Snowman, yes it is fascinating the span different relatively defined areas/volumes can differ quite much between different individuals. Would be interesting to see a study on say extreme versions/sizes of primary visual cortex, and perform a lot of cognitive/performance tests on these extremes. See if relatives have extremes. Check for their occupation/training/hobby etc.
1 / 5 (1) Dec 08, 2010
and check for light conditions they might have grown up under, visual acuity, pattern recognition ability and thousands of other parameters

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