Pride yourself on your ability to read and respond to email and keep up with your SMS messages on your Blackberry while you're scouring Google, and checking out movie session times on your notebook PC, and simultaneously watching the latest episode of your favourite TV series?

The latest research from Stanford University suggests that far from having superb control over your attention, you're in fact paying a heavy price for all that multi-tasking, in the form of mental distraction and diminished performance.

 A series of tests by researchers showed that high multitaskers significantly lagged behind people who tend to focus on one thing at a time. They were routinely distracted by irrelevancies, and had poorer memory recall.

The researchers haven't reached a conclusion yet on whether chronic multitaskers are born with an inability to concentrate or are impeding their cognitive control by taking in too much at once, but they are convinced that their inability to filter means their minds are not working as well as they could.