Regularly the words would rip through my small body like a knife: "Daydreaming again, Anne Johnstone!

Sit up and pay attention!" It was the shrill voice of my primary school tormentor, Mrs Ashton. Looking back across half a century, I think I spent most of my first decade with my head stuck in the clouds. It felt like a sensible place to be for a shy, bespectacled, buck-teethed dyslexic with skinny plaits but to my tyrannical teacher this silent soliloquising was merely confirmation of inherent laziness.

All this came to mind yesterday in a so-called idle moment, on hearing that two academics were busy telling the annual conference of the British Psychological Society that boredom makes us more creative. Why? Because it gives us time to daydream. Their two studies suggest boredom gives the mind a chance to wander in a way that enhances bursts of creativity.

Others have come to similar conclusions. So, while Freud dismissed daydreaming as "infantile" and merely a way of coping with boredom, more recently psychologists have discovered it is a vital cognitive tool, enabling the brain to relax and refresh itself and to hypothesise different possibilities. It's been described as "eavesdropping on the unconscious".

Meanwhile, neuroscience shows that despite the "vacant" facial expressions of daydreamers, several parts of the brain remain fully engaged.

So what is daydreaming? In 1927 Virginia Woolf came up with a delightful depiction in To the Lighthouse, when describing Lily Briscoe: "And as she lost consciousness of outer things ... her mind kept throwing up from its depths, scenes and names, and sayings, and memories and ideas, like a fountain spurting."

Surely she would have loved the splendid Scots word "dwam", which featured as The Herald's Scots Word of the Week last September where its definitions included swoon, trance and pleasant daydream. Another authority, Betty Kirkpatrick, a former editor of Chambers Dictionary, translates "in a dwam" as "staring into space" or "lost in thought" and notes there is no exact English equivalent.

In a culture increasingly obsessed with efficiency and the micro-management of time, when our streets are thronging with pedestrians chattering on mobiles or peering at tiny screens, are such mental meanderings under threat?

Last week a survey revealed we Brits spend an average of nine hours a day glued to screens. That's equivalent to 132 days a year or 37.5 years over an 80-year lifespan. Are we eclipsing vital dwam time as we rush from our workstations to checking our smart phones as we commute home to slump in front of the telly or prattle on social networking sites?

It's going to get worse, according to one consumer trends website. Our 18 to 24-year-olds already exchange an average 109 messages every day. Among predictions for 2013 is "mobile moments or lifestyle hyper-tasking".

"Consumers will look to their mobile devices to maximize absolutely every moment," it rejoices, adding: "Hectic urban lifestyles mean no amount of micro time will be too fleeting or activity too absorbing to cram in more content connection, consumption or simply more fun."

How depressing. If our kids are seamlessly moving from one screen-based activity to another, what will happen to all those little reveries we once used to incubate all those ideas milling around in our stream of consciousness?

Today I look back on my daydreaming in the back of Mrs Ashton's class as a form of deep relaxation or self-hypnosis that rendered bearable what seemed a rather bleak and unpromising life. It was a blessing in disguise that enabled me to switch off from all my day-to-day worries.

I hope my own children find time in their non-stop lives to dwam a little. In the words of an anonymous poem called Dare to Daydream that I stumbled on yesterday: "Choose a wish, find a dream, pick a lucky star. Let your hopes and spirits soar, high and free and far."