High scores in these tests tend to correlate with high scores on measures of depression and impulsivity. But it is not clear which comes first -- proneness to boredom, or the mood and behaviour problems. “It’s the difference between the sort of person who can look at a pool of mud and find something interesting, and someone who has a hard time getting absorbed in anything,” said Stephen J Vodanovich, a psychologist at University of West Florida in Pensacola.

Boredom as a temporary state is another matter, and in part reflects the obvious: that the brain has concluded there is nothing new or useful it can learn from an environment, a person, an event, a paragraph. But it is far from a passive neural shrug. Using brain-imaging technology, neuroscientists have found that the brain is highly active when disengaged, consuming only about 5 per cent less energy in its resting “default state” than when involved in routine tasks, according to Dr Mark Mintun, a professor of radiology at Washington University in St Louis.

That slight reduction can make a big difference in terms of time perception. The seconds usually seem to pass more slowly when the brain is idling than when it is absorbed. And those stretched seconds are not the live-in-the-moment, meditative variety, either. They are frustrated, restless moments. That combination, psychologists argue, makes boredom a state that demands relief -- if not from a catnap or a conversation, then from some mental game.

“When the external and internal conditions are right, boredom offers a person the opportunity for a constructive response,” Dr Belton, co-author of the review in the Cambridge journal, said.

... contd.