Mind-boggling optical illusion tricks your brain into thinking these faces are different colours – but they’re actually identical

From the cigar nestled in the brickwork to ‘The Dress’, many optical illusions have baffled viewers over the years. 

But the latest illusion is arguably one of the most mind-boggling yet. 

The illusion has gone viral across social media, and feaures two cartoon faces. 

So, what colour do you think the faces are? 

Your initial reaction is probably that the face on the left is white, while the face on the right is black. 

However, when they’re placed together, you’ll find that the two faces are actually identical shades of grey. 

The illusion has left many people scratching their heads, with one tweeting: ‘this is hurting my head why is it real.’ 

Another added: ‘I’ve seen this kind of trick before but this is easily the most convincing version of I’ve ever seen.’

On the surface, the illusion is very basic, and simply features two winking cartoon faces. 

The face on the left is set on a dark green background, while the one on the right is shown on a light green background. 

Several other features are different colours across the two images – including the hair and the eye. 

However, the faces themselves are actually identical shades of grey.  

The origin of the cartoon illusion remains unclear, although it has been widely shared across TikTok, X, and Facebook. 

In TikToker SmartFactFeed’s video, they show the two faces merging together to confirm the colour is the same. 

‘At first glance, the two faces seem to be different shades, but this is only due to the surrounding hair color and background shading,’ it explained in the caption. 

‘When placed together, you’ll see they are, in fact, the exact same color and shade. 

In TikToker SmartFactFeed’s video, they showed the two faces merging together to confirm the colour is the same

‘Yet, the illusion remains, as your perception is still influenced by the background and neighboring colors.’

This is what’s known as a ‘colour saturation optical illusion’, and comes down to the ways our eyes view and perceive colours and brightness. 

‘The way we view colours and brightness is due to the cells we have in our retina at the back of our eye,’ Lenstore explains. 

‘The cones are the judge of colour, and the rods judge the brightness of the image we are seeing.

‘These two cells send information to our brain through the optic nerve and the brain from that signal tries to interpret what we see. 

‘When judging colour, the brain perceives it differently when it is compared to what is surrounding that object.’

The illusion has been widely shared, with many viewers expressing their disbelief. 

‘Actually insane how this illusion works. I cant even describe it,’ one user wrote on X (formerly Twitter). 

Another added: ‘I never realize how powerful color context is until images like these appear.’

And one joked: ‘It’s the dress all over again.’

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. 

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

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.