How pop-ups slow your PC

Although pop-ups on a computer screen may only last a few seconds, they tend to set back our performance, say researchers.

Helen Hodgetts and Dylan Jones, professor of psychology at Cardiff University, examined the cost of such interruptions in terms of the time taken to complete a simple seven-step computer task.

"Our findings suggest that even seemingly brief and inconsequential on-screen pop-up messages might impact our efficiency, particularly given their frequency over the working day," says Hodgetts.

They found that, even after only a five second interruption, people take longer than normal to complete the next step in the task they are working on.

But in a more realistic work environment, where there is more information to retrieve after the interruption, the loss of concentration could have a greater impact on performance.

Other results from the study show that an interruption lag -- a brief time between a warning for a pop-up and the interruption itself -- can reduce the time we lose trying to find our place again.

A warning sound was found to be most effective because it allows us to consolidate where we are in the current task before transferring our attention to the interruption.

Conversely, a flashing warning signal on the screen can be just as disruptive as the interruption itself, said a Cardiff release.

Researchers suggest that e-mail alerts and similar pop-up messages should be as small and discreet as possible and should not obscure the original activity.