You apparently have a high IQ if you can spot the hidden dog in this viral photo within 20 seconds. 

Cognitive challenges have become increasingly popular online, with people having fun finding hidden objects or animals.

Recently, one was trending involving a hidden tiger in the jungle, which left some social media users stumped and asking others for the answer.

Now, another image is circulating on Reddit, with a user asking others if they can spot the hidden dog in the snow-covered forest.

The challenge is to be able to identify the dog in 20 seconds.

At first glance, it seems impossible that a canine is hidden somewhere in the snow – but those with a sharp eye may be able to see it.

Those who can spot the four-legged animal quickly apparently have a high IQ.

Many in the comments can’t find the dog, with one person writing: “I do not see it!”

Another adds: “I have been staring at this photograph for ages now.”

“Even with the clues in the comments, I still can’t find it,” a third admits.

Someone else says: “I think y’all lying if y’all said you found it.”

An optical illusion involves the brain interpreting an image differently from how it is in reality. Sometimes, like with the image of the dog in the snow, the brain becomes confused about what the eyes are seeing, as per The University of Queensland Australia.

When people can’t figure out optical illusions, the brain may fill in the gaps where there is incomplete information.

This is down to evolution, with survival depending on fast reactions – it puts the pieces together to create a quick response, as per the American Museum Of Natural History.

Associate Professor Paul E. Dux, from the School of Psychology at the University of Queensland, explains: “How people search through space and a visual environment. Basically, you present stimuli and you’re finding a target in a mass of distracting objects,

“The reason why some people find it and others don’t is because some have better ‘spatial attention’ than others.”

Those who spotted the dog hidden in the snow were also quick to boast about finding it right away, with one Reddit user saying: “That was easy, his ears gave it away.”

A second writes: “Spotted straight away!”

“Yup… found the dog,” comments another.

For those who can’t see the hidden dog in the snowy forest, a handy tip is to look out for the canine’s ears, eyes, and nose, which stand out against the snow.

If you focus on the center of the image, it should make the dog much easier to find.