Researchers from Johns Hopkins have come up with a way to test your ability to focus that should take less than 10 seconds. 

It doesn't rely on how fast you can add sums in your head or recite history from memory.

Instead, asks you to call on skills you might've developed during Where's Waldo. 

 It asks participants to look at a screen with many different symbols on it in three different colors. 

Then, they are asked to find a letter, in the case of this example, the letter 'T'. 

Before this, they are either given no instruction, or told that the letter they are looking for isn't a certain color. In this example, they are told 'The T is NOT red'. 

The Johns Hopkins researchers found that people who were able to pay attention to these caveats were able to find the T faster than those who had no prompting, after a few rounds of practice. The more information they were able to ignore, the faster they found the T. 

These findings, which were published in the journal Psychological Science, give us a better understanding of how our brains are able to process and use multiple bits of information at the same time.  

It also shows how the ability to ignore certain ideas is a key part of paying attention.  

Professor Howard Egeth, who studies psychological and brain sciences at John Hopkins said he thinks of this as the 'dark side of attention.' 

It's in contradiction to a series of earlier studies which suggested that people who are searching for an item are always slowed down when prompted with things they should ignore. 

This is crucial information for people who need to rely on their visual searching skills in real life, Corbin A Cunningham, the study's lead author, who was a graduate student at Johns Hopkins at the time, said. 

'Individuals who explicitly ignore distracting information improve their visual search performance, a critical skill for professional searchers, like radiologists and airport baggage screeners,' he said. 'This work has the potential to help occupations that rely on visual search by informing future training programs.'