From the ‘Moon Illusion’ to ‘The Dress‘, there have been many baffling optical illusions discovered over the years.
However, this festive illusion might be one of the most perplexing yet.
This visual trick has been shared across social media and features a magically appearing Christmas tree.
During the intense illusion, viewers’ brains are tricked into seeing a bright green tree.
However, in reality, the image actually remains black-and-white while your brain provides all the colour.
In a TikTok video, radio presenter Dean Jackson shared this baffling illusion to the amazement of social media.
One shocked commenter wrote: ‘I saw a green tree with colored bulbs. I played it again to make sure the ending was really black and white. AMAZING!!!’
So, what colours can you see?
To make the illusion work, you first need to look closely at the coloured image.
In the video, Mr Jackson says: ‘Have a look at this picture, stare at the red cross in the middle there. Focus on it intensely and try to block out everything else.
‘In a few seconds’ time, I’m going to wipe the picture and replace it with a black-and-white one and I’m hoping that your brain will fill in the missing colours.’
If you keep your eyes focussed on the cross as the colour vanishes, you should see the impression of a green tree with coloured decorations and presents.
Many social media users flocked to the comments to share their experience with the illusion.
One commenter wrote: ‘The red turned to blue the green turned to magenta the pink turned to green the blue turned to orange but the star turned yellow instead of orange.’
‘Very clever, saw a green tree and decorations,’ added another.
While one commenter wrote: ‘The colors turned pastel!! The tree turned green the star is yellow and the ornaments were pink.’
While the image on the screen is actually black-and-white your brain is tricked into seeing the colours due to an effect called the afterimage illusion.
Just like looking at a bright light leaves spots in your vision, looking at any colours can cause you to see afterimages.
When you see a bright colour, light-sensitive cells in your eyes called photoreceptors become overstimulated and fatigued, causing them to lose sensitivity.
Normally, you wouldn’t notice this effect because your eyes are constantly making tiny movements which prevent the photoreceptors from becoming overstimulated.
However, by staring intently at the red cross you are preventing those movements from happening so that an afterimage can form.
The reason that you see a green tree is due to something called the ‘opponent process theory’ of colour perception.
This theory claims that your vision is controlled by two systems: one which detects magenta and green, and another which detects blue and yellow.
Within each system, the two colours balance each other out so that you see a normal mixture of tones.
But when one group of receptors is fatigued the other over-compensates and produces an inverted afterimage.
Since magenta normally balances against green, the bright magenta tree creates a green afterimage.
However, some scientists now believe the afterimage illusion may be far more complex than once thought.
In 2001, researchers from the California Institute of Technology in Pasadena made the strange discovery that optical illusions could also create afterimages.
They found that the brain would continue to see colours created by a well-known illusion called ‘perceptual colour filling’.
But since there is no colour, it can’t be the case that the viewer’s retina were getting fatigued.
This suggests that afterimages might be formed by adaptions in the brain itself, rather than in the eyes.
WHAT IS THE DELBOEUF ILLUSION?
The Delboeuf illusion is one type of visual illusion where a dot surrounded by a large ring is typically perceived to be smaller than the same-sized dot surrounded by a small ring.
This optical trick works because your brain perceives the dot in the context of the outer ring.
It was named after the Belgian philosopher and mathematician Joseph Remi Leopold Delboeuf (1831 – 1896), who created it in 1865.
In terms of plate size, the theory goes that having a smaller plate tricks people into thinking they have more food.
However, new research suggests that when people are hungry, they are able to identify food portion accurately, no matter how it is served.
According to the researchers, this indicates that hunger stimulates stronger analytic processing that is not as easily fooled by the illusion.
However, the Delboeuf illusion is widely believed to work in other contexts.
