How observant are you? Can you spot the T in this video test?

'Individuals who explicitly ignore distracting information improve their visual search performance'

The video above asks people to to find the letter T among a jumble of shapes with and without hints of what colours to ignore.

It was created by Johns Hopkins University(JHU) as part of a study into how the ability to ignore things affects people's ability to spot key details.

The study published in the journal, Psychological Science, found that knowing what to ignore could be just as helpful as knowing what to look for.

Lead author, Corbin A Cunningham, from JHU's Attention and Perception Lab, said: "Individuals who explicitly ignore distracting information improve their visual search performance, a critical skill for professional searchers, like radiologists and airport baggage screeners."

Study participants were asked to search for certain letters on a computer screen among other letters of different colours.

Sometimes they would be told what colour the letter would not be and other times no colour hints would provided.

At first these eliminating hints slowed down responses. However, after hundreds of trials, participants became far more efficient when they knew how to compute what to ignore.

Co-author Howard Egeth, a professor of psychological and brain sciences, said: "Attention is usually thought of as something that enhances the processing of important objects in the world

"This study, along with some recent work in which we measured brain activity while subjects responded selectively to stimuli presented in the midst of competing stimuli, highlights the importance of active suppression of those competing stimuli.

"It's what I think of as the dark side of attention."