About 12 years ago I made a decision to stop shouting at my children. As a means of crowd control in the family home, shouting does not work. It can be surprisingly easy to change the habits of a lifetime (my children's lifetime anyway). To aid me in this endeavour, I turned off the radio. The noise level plummeted. The squabbling and shouting that vied to be heard over fresh disasters on the radio stopped. I became calmer, the children much quieter; in fact, silence reigned in our house in the mornings. It was wonderful. A new pattern established itself very quickly and I smugly joined the ranks of mothers who don't shout. Well, rarely.

Increasingly, we are allowing visual images from television and external sound to intrude on our reality. It is impossible to avoid in our urban society, with piped music, radio or television in our homes, pubs, supermarkets, waiting rooms, cars. It is common to find both television and radio on in the same pub. My most recent count was three televisions (one of them large screen) and radio on at the same time. Requests to turn down music are usually met with blank incomprehension. I've no doubt I'm considered downright eccentric.

So if everyone wants music, radio or television within earshot, does it matter? Surely it can't do any harm? Doesn't it help us relax? The contrary seems to be the case. Attention to reality, what is actually going on, becomes less focused with background noise. We become more preoccupied. We become distracted, unable to give attention fully to one thing or the other.

There is nothing children like more than undivided attention.

Mothers often notice that when they are having a conversation with a friend, especially on the phone, their children become much more demanding and disruptive. Children need to be listened to attentively, with our ears, our eyes and our bodies - getting close and down at their level.

Parents with whom I have worked have invariably found that reducing background noise has helped in managing their children's behaviour. The children have become calmer and conflict within the house has been reduced, leading to a reduction in the overall stress levels.

In 1984 Dr Sally Ward, a speech and language therapist in Manchester, investigated the listening skills of nine-month-old babies. She found that 12 per cent of those in the study showed delays in listening skills. In a further study in 1991, she found that 20 per cent of nine-month-old infants were delayed in listening skills. This had risen to a staggering 30 per cent in 1996.

In order to develop language and learn to speak, children need to develop selective attention. In other words, they need to learn what to listen to. Think about it: if you paid attention to everything you hear, you'd go mad. We need to select what we want to listen to, and tune out the rest. If infants in their first year are exposed to fairly constant sound, they are going to "tune out". What seems to be happening is that they are also tuning out their mothers' voice as well. They do not know that her speech is more important than the voice-over in the latest ad for washing-up liquid.

There is considerable evidence that the development of selective attention in infants can be seriously impaired in excessively noisy environments, particularly in their crucial first year. This can lead to impaired language development, which can affect the child's emotional and social development. Impaired language is more likely to lead to reading and other learning difficulties later on.

In Ward's study, the children were divided into two groups, the study group and the control group. In the first group, speech and language therapists spent one session a month for four months with each child and its parent. The control group had no intervention. The programme of intervention was planned to assure the infants developed selective listening. It was childishly simple. Although the programme was geared to each child's needs, the general advice could not be simpler: turn off background noise; get close to your child; speak a little louder; speak a little slower; use lots of tune in your voice; chat to your child.

Within four months the children who were seen by the speech and language therapist were developing normally and their language development continued to accelerate. Meanwhile, 30 per cent of the control group had been referred for speech and language therapy by their third birthdays. None of the children who were part of the intervention programme was ever referred for therapy.

The final, stunning, results of the study were broadcast on BBC TV's Tomorrow's World recently. The study-group children are now eight years old and all show excellent language development - but also show an higher-than-average intelligence. On average, they were 15 months ahead of "normal" for their age, with an unexpected number of IQs in the "gifted" range.

Many people tell me that they love the company of the radio and find silence hard to tolerate. However, by turning our backs on silence we are more and more passively observing life rather than actively participating in it. We cannot focus our attention on the present moment and activity if there is constant sound vying for our attention. I'm not suggesting we get rid of radios or television. I'm suggesting we make a decision about what we listen to and watch by selectively choosing the programmes that interest us and setting an example for our children to follow. We need to take greater control of the role technology plays in our lives, so that it is enhancing rather than diminishing our quality of life. Even deciding to turn off for 15 minutes is a start. And then notice the effects on yourself and your children.

Eileen McCann is a senior speech and language therapist with the North Eastern Health Board.