It has been one of the hottest must-have accessories for the cultured American baby for the last few years.

It is not a designer baby-grow, nor a hi-tech cot toy, but a classical music CD of Mozart's Sonata in D Major.

Ever since scientists published research suggesting that it could make children more intelligent, parents have been buying up almost every available copy; nursery schools have been dutifully playing it to their charges; and some American states have even been sending out free copies to families with a new-born child.

The Mozart myth?

But they have all been wasting their time, according to the latest research.

The latest research says Mozart has no more effect than other music or random noise

"The bottom line is that there is no Mozart effect," says Kenneth Steele, psychology professor at Appalachian State University, referring to the increase in spatial reasoning the sonata is said to produce in young children.

When he played the sonata to youngsters, he said it had no more effect on their intelligence than contemporary music, or even random noise did.

Professor Steele is one of a number of scientists debunking the popular theory.

John Bruer, head of the McDonnell Foundation in St Louis, is about to publish a book called The Myth of the First Three Years, in which he rubbishes the whole notion that a single piece of music can have an impact on a child's intelligence.

Experienced experts

But in a nursery school classroom in downtown Manhattan, where classical music routinely vies with the shrieks of two and three year olds, teachers calmly greet the news that it may not be having the desired effect on the toddlers' spatial reasoning.

Teacher Charlene Darnell has played Mozart, as well as Bach, Beethoven and Schubert, to her young charges for years, and she is not about to stop just because a few scientists say she is wasting her time.

Kids do not care if the music makes them smarter

"I use music with painting sessions. I use it to teach the kids about meditation and being quiet. I use it in all sorts of ways," she says. "It's just another vehicle that aids in brain development. I never thought music would make kids more intelligent on its own, but combined with other things, it definitely helps."

As they leap around the room in time to Tchaikovsky, 4-year-old Mona, Mary and Rowan do not really have an opinion about whether it is sharpening their powers of reasoning. But they do know they enjoy the music their teacher plays them.

"I feel like I'm inside it," says Rowan.

"It makes me feel like I'm in bed with a cosy blanket, snuggling up with my teddy bear," adds Mary.

"I like to dance to it," interjects Mona.

Music appreciation

What is clear is that all the children appreciate the music they hear for a variety of reasons.

Not just the particular Mozart sonata credited with such intelligence-enhancing properties, but all sorts of different sounds.

And according to Dr Stanley Greenspan, who has written several books about brain development in young children, that is what counts.

"The issue isn't whether listening to Mozart is specifically helpful for spatial reasoning," he says. "That's far too specific a question. The issue is whether music in general enhances critical development in young children, and there's a lot of evidence that music is very helpful."