Teachers' failure to understand that children's brains cannot truly "multitask" is leading to substandard and slower learning in schools, a leading psychologist has warned.
Asking students to do too much at once could even be adding to the problem of shortening attention spans, said JoAnn Deak, an academic and writer. Dr Deak, author of The Owner's Manual for Driving Your Adolescent Brain and a former science teacher, said that just asking children to take notes at the same time as listening was too much for young minds.
"Deep understanding cannot be reached if a child is trying to write at the same time," she said. Listening to an explanation while watching the teacher draw diagrams on the board was also a problem because students could not simultaneously process what was seen and heard.
"Some extremely talented teachers may have noticed this, but the reason most do not is that the stuff they are teaching, for them, isn't complex," Dr Deak said.
The explosion in technology in the classroom was another problem, she added. Tablets and laptops could be a huge distraction, with many children focusing on spelling and fonts, rather than listening to and understanding the lesson.
Her warning comes as a row over the best ways to teach intensifies in the UK, with leading Conservative politicians calling for an end to "child- centred" learning and a return to more traditional lessons.
Meanwhile, Tristram Hunt, the Labour Party's education spokesperson, this week called for students to be taught "attentiveness" to overcome the influence of social media. "They need to learn the ability to concentrate for sustained periods, especially in today's world of short attention spans," he said in a newspaper interview.
Dr Deak, an educational consultant to schools and organisations around the world, warned that schools were contributing to the "barrage" of multiple activities that young people's brains were being tasked with in modern life, such as social networking and texting.
"[Research shows] that kids are getting worse at being able to focus for long periods of time," she told TES. "We are actually causing some attentional issues by the kind of multitasking that's going on.
"If you're jumping from one thing to another over a long period of time, your brain gets used to that. Then, when you ask it to focus on one thing for any length of time, it gets bored.
"[Children] lose focus because they need that multiple barrage, otherwise it doesn't feel as fast and good and interesting."
To overcome the issue, children should be allowed to do only small amounts of note-taking after the teacher has spoken.
Once they had learned not to do more than one thing at a time, children could apply those lessons at home, Dr Deak said, and do homework without simultaneously trying to listen to music, message their friends or play computer games.
Al McConville, director of teaching and learning at Bedales, a private boarding school in Hampshire, England, said his school had tackled the problem of children's increasingly divided attention through "mindfulness" courses.
This practice - where students consciously empty their minds of distractions - could improve learning, he said. "What people can get better at is quickly switching their attention, since true multitasking is impossible.
"People who are good at that have a good executive function, the ability to control and focus."
Dr Deak's comments come just weeks after it was announced that the UK is to pioneer the application of neuroscience in the classroom, with the launch of a pound;6 million fund for research. Ten projects in hundreds of schools will test whether better understanding of neuroscience can improve learning.