Television and poor diet making children unteachable, report Graeme Paton, Nicola Porter and Karen Thornton
Ten "toxic" ingredients of modern life are making our children harder to teach than 30 years ago, a leading educational consultant has warned.
Sue Palmer spent three years interviewing teachers and academics before identifying a damaging mix of technology, family breakdown and poor diet.
She says these factors explain worsening behaviour and an explosion in numbers of special-needs pupils.
Her study emerged as the Assembly government announced a major review of pupil behaviour, discipline and attendance.
Ms Palmer, a writer on literacy and childhood, believes parents could help address the behavioural slide by having regular family meals and taking televisions out of children's bedrooms - where they are subjected to "damaging" influences without censorship.
Her findings follow the publication of a study of 10,000 pupils earlier this year, which revealed a dramatic drop since 1976 in the number of 11-year-olds who are able to grasp basic maths and science concepts.
The number of children being diagnosed with attention deficit hyperactivity disorder (ADHD) has soared in recent years. And a report last month said NHS prescriptions for a drug to treat the condition had increased three-fold since 1999.
Ms Palmer, who is a TES contributor, said: "On the whole, children are more distractible and impulsive than a few decades ago.
"This causes problems with discipline in school and in settling them to learn. It is a significant factor in the problems that we have teaching reading, and the explosion in special needs."
Her research, which was to be presented at the Education Show in Birmingham yesterday, identified 10 causes of the behaviour shift: access to modern technology, a lack of outdoor play, poor sleep patterns, lack of communication with adults, the testing culture in schools, pressure from advertisers, changes in family structure, poor advice to parents contributing to worsening manners, sleep deprivation and diet.
Ms Palmer's findings will be published in a book, Toxic Childhood, in May.
They come as Jane Davidson, education, lifelong learning and skills minister, announced this week a major review of pupil behaviour and attendance in Wales.
The Education and Inspections Bill, currently before the Westminster Parliament, will allow Wales to develop its own legislative approach to the issue, including on parental responsibilities and educating excluded pupils.
But she wants any changes to be based on clear evidence and developed in consultation with schools and the wider community. The review will look at "good and not-so-good practice", and involve children's charities and children's commissioner Peter Clarke, she added.
The influence of parents and the effects of diet on children's behaviour were acknowledged in an opposition amendment carried by the Assembly. Plaid Cymru's Jocelyn Davies (South Wales East), said: "Diet has a profound effect on behaviour. Parents who can't cope should have much more support than they do at present."
But a Conservative motion calling for guidelines for teachers on the right to confiscate property, place pupils in detention, and use appropriate measures to restrain violent pupils was not agreed.
Meanwhile, another study this week cast doubt on the link between television and behaviour. Researchers at Texas Tech university followed two groups of 2,500 children, tracking their viewing habits over a two-year period from age five.
It found that their exposure to television had no bearing on their risk of contracting ADHD later.