Brain Games Color Illusion Black and White

Forget the black and blue dress, this monochrome castle is the latest image to demonstrate just how sophisticated our brains are at viewing the colours we see around us.

The strange optical illusion works by priming the receptors in the retina of our eyes so they recreate colour in a back and white image.

By staring at a dot in the centre of the first photo, the cells of the eye that see colour become desensitised and later attempt to 'fill' the monochrome scene with the colours that it is missing.

Scroll down to see the optical illusion in action in a video

The trick works by creating a false colour image of a black and white photograph (pictured) to desensitise the cone cells in the retina at the back of the eye. Stare at the blue dot at the centre of the image for 30 seconds before scrolling down to the black and white image below, where the coloured scene should become clear

The trick works by staring at the dot in the centre of the false-colour image for around 30 seconds.

This causes the cone cells in the retina - each of which detect either red, green or blue light - to 'become tired of and ignore' the colours being stared at.

When the monochrome scene is restored, the remaining cone cells responsible for detecting other colours than the ones being staring at 'fill in' the scene.

IS COLOUR ALL IN THE MIND?

Roses aren't red and violets aren't blue.

At least that's the premise of a new book, 'Outside Color', which puts forward the debate that colour is, in fact, an illusion.

Author Dr Mazviita Chirimuuta uses the book to explore the historical debates that suggest colour doesn't exist - at least not in the literal sense.

Light, however, does exist, and it's the mind that transforms that light into colour.

'Of all the properties that objects appear to have,'writes the University of Pittsburgh professor, 'colour hovers uneasily between the subjective world of sensation and the objective world of fact.'

This means the false-colour image acts like a sort of 'negative' for the scene.

Dr Helen Czerski, a physicist at University College London, revealed the illusion using a picture of Dunstanburgh Castle as part of her series about colour for the BBC.

She said: 'By staring at the dot in the middle of the screen, my brain, and if you do it your brain, is doing something remarkable.

'I find this absolutely fascinating.

'In my head a full colour image was created of a photograph that clearly contains no colour.'

The trick works due to an effect known as 'afterimage'.

This is where overexposure to a given colour causes the retina to become tired of that colour and desensitises the cone cells to it for a short period.

When the colour stimulus is removed and the eye is exposed to a black and white image under white light, then the complementary colour is perceived for a brief period of time.

Dr Czerski demonstrated the illusion as part of BBC Four's Colour: The Spectrum of Science to help explain that often the way our brains interpret colour can cause it to become confused.

She said the recent internet sensation caused by the white and gold dress, which some saw as being blue and black, was a good example.

She said: 'As we were making the series, I asked members of the public for their questions relating to colour, and I've answered some of the most popular ones here.

'One question stood about among the rest because it was asked again and again. People really care about it.

By continuing to stare at the scene after looking at the false colour image, the black and white information in the photograph should be covered with colour, just like the real scene. After a few seconds the effect wears off

'The question is: "Is the colour you see the same as the colour I see?"

'I think that the reason people asked is because they want reassurance: colour is so important to us that it's vital it's the same for everyone.

'Otherwise, how do I know that my interpretation is right or whether it means anything at all?

'Surely a red apple is red, and that's the end of it. But how do you check? And then along came The Dress.

'It turned out that people don't always interpret the world in the same way and it made such huge social media waves because it seemed so unbelievable.'

WHY THE BLACK AND BLUE DRESS APPEARED WHITE AND GOLD

'The Dress' caught the public's imagination in February, after a photo of it was posted on Tumblr. Some people were adamant it was blue and black. Others insisted it was white and gold.

Scientists from the University of Bradford and University of Giessen in Germany say the disagreements were likely caused by the mechanism the brain uses to ensure an object is seen to be the same colour, no matter what time of day it is and what type of light it is bathed in.

In bright, midday sun, daylight is blueish and so the brain subtracts blue light. Under artificial light, it gets rid of yellows - and in both cases the object should appear the same.

In bright daylight is blueish so the brain subtracts blue light. Under artificial light, it gets rid of yellows. Crucially, it relies on other nearby colours, such as reds and greens, to work out how much light to remove. In the case of the dress, these reference colours were missing and the brain had to rely on experience

Crucially, it relies on other nearby colours, such as reds and greens, to work out how much blue or yellow light to remove.

In the case of the two-tone dress, these reference colours were completely missing, and the brain had to rely on experience.

Add in the fact that blue is particularly tricky for the brain to deal with and some people got it wrong. They took away too much blue and saw the dress as white and gold.

In contrast, others subtracted the yellows, and rightly perceived it as blue and black.

Neuroscientist Bevil Conway, from the Massachusetts Institute of Technology, who asked more than 1,400 people about 'The Dress', added it is likely that people who spend a lot of time outdoors, or had just been in daylight, took away too much blue and saw it as white and gold.

While those more used to artificial light subtracted yellows and perceived it as blue and black.

MailOnline got hold of a copy of the dress (pictured) and was able to confirm that it is black and blue

This could explain why young people, who tend to spend more time indoors and stay up late, were more likely to see it as blue and black.

And why women, who are less likely to be night owls than men, veered towards white and gold.

Professor Andrew Lotery from the University of Southampton told MailOnline everyone has different combinations of the genes that create the sense of colour and because these genes are on the X chromosome, women tend to have more variations.

This may explain why women flip between seeing the different colours, and men typically don't.

He added that some people have more than one 'dose' of a blue colour gene, as an example, so they will see higher or lower levels of this colour, too. Additionally, as people get older their perception of colour changes.

The lens of the eye gradually yellows with age and this exposes more blue, continued Professor Lotery.

This will influence how deep or strong a colour appears and could explain why older people may see the blues and blacks rather than the whites and golds.

Brain Games Color Illusion Black and White

Source: https://www.dailymail.co.uk/sciencetech/article-3320480/The-image-HACK-brain-Optical-illusion-transforms-black-white-picture-colour-simply-staring-it.html

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