Do those Where's Wally type puzzles drive you nuts? Or do you revel in your ability as a speedy spotter of the panda among the snowmen, or the cat in the kitchen?

Whichever it is, there's a scientific explanation behind your ability, or lack of, when it comes to optical illusions.

Associate Professor Paul E Dux, from the School of Psychology at the University of Queensland, told the difficulty with locating the likes of the panda among the snowmen comes down to some people having stronger "special attention" than others.

"Panda among the snowmen is really focusing on visual search, which is a major topic of investigation," Professor Dux said.


He explained it as studying the way people search through space and a visual environment. "Basically, you present stimuli and you're finding a target in a mass of distracting objects," he said.

And the reason why some people find that panda and others don't? "...because some have better 'spatial attention' than others."

With the panda image, which went viral after appearing on Facebook just before Christmas, Dux says it's an example of just how difficult it is to find a slightly different item among similar ones.

"The panda and snowman image is similar to if you're looking for coriander amongst an aisle of other greens. That's what we call an inefficient visual search, which is why people struggle to locate the panda."

So what's the trick to cracking these visual puzzles?

According to Inside Science, it comes down to the relationship between the eye and the brain.

The way some of us notice an image within an illusion is down to picture fooling the brain, taking advantage of visual "shortcuts".

Science filmmaker Kirk Zamieroski wrote: "When you look at something, what you're really seeing is the light that bounced off of it and entered your eye, which converts the light into electrical impulses that your brain can turn into an image you can use."

He said the process takes about a tenth of a second, but because our eyes receive a constant stream of light - which allows for a huge amount of visual information - it's hard for the brain to focus on everything at once.

"It would be like trying to take a sip of water from a fire hose. So your brain takes shortcuts, simplifying what you see to help you concentrate on what's important, which helps compensate for your brain's tenth-of-a-second processing lag."

Optical illusions fool our brain by taking advantage of its shortcuts.