Talking to teen parenting gurus Janey Downshire and Naella Grew is depressing, to say the least.

Don't get me wrong – they are charming, sensible, full-of-solid-advice experts in their field. But the image they paint of how our teens are sleep-walking into a lifetime of being unable to concentrate on anything long-term, be that reading a book or watching a screen, is simply terrifying.

I spoke to the women, who boast six teens between them, about the emergence (in my own household too), of TV-watching youngsters who keep only one eye on the big screen, whilst flicking through umpteen other screens on their i-pad/mobile/tablet/lap-top/other.

"A teenager's brain is naturally programmed to seek out the most exciting and novel of things, so it's understood they will be looking at different screens and sources of information at this stage," explains Naella.

"But it's crucial that they also need to start training their brain to linger, to concentrate, to really focus and process information – because this state of constant sensory overload and hyper-arousal of the brain is not actually helpful," she says.

My heart sinks further when Janey, who with Naella has co-authored 'Teenagers Translated: How to Raise Happy Teens', chips in: "As adults we have mastered the art of impulse control and know that it is better to do one thing at a time well, rather than starting lots of different tasks."

Is this woman really saying that multi-tasking isn't all it's cracked up to be? I think she is. When I think about it, in my own life I have a pretty scattergun approach to tasks. I can often be found ironing, emptying the dishwasher, peeling the spuds, writing a piece, putting out the rubbish and shouting at my kids to bring down their dirty washing. The result is that I am forever saying "now where was I?" and having to really think about what I need to do.

"Exactly!" says Naella. "Teenagers are only mirroring this behaviour with their screens." She refers to research by the psychologist Professor David Meyer at the University of Michigan, who has spent the last few decades studying multi-tasking in adults. Whilst there's not much research into multi-tasking teens, the findings will ring true with many of us.

"For tasks that are at all complicated, no matter how good you have become at multi-tasking, you're still going to suffer hits against your performance. You will be worse compared to if you were actually concentrating from start to finish," he says.

Read the full article "Teenagers translated: How to raise happy teens" at MSN.