Babies in the womb can hear and remember music as early as 20 weeks gestation, according to research at Keele University.

Stephen Evans and Richard Parncutt, psychologists, asked expectant mothers to play folk music loud enough for the sound to penetrate the womb. After the babies had been born, there were signs that they recognized the tunes, even those played to them in the 21st week.

The results, described by Mr. Evans as "astonishing," have implications for fetal development.

Fifteen pregnant women took part in the experiments. Ten played the music to the unborn children, five did not. The ten were given two tapes, one of Welsh folk music and one of Devonshire folk music. The tunes were unfamiliar to the women. They were asked to play one tape at 20 and 21 weeks of pregnancy, and the other between 30 and 31 weeks. The volume was adjusted so that it could be heard above a washing machine, yet not loud enough to annoy the neighbors.

Two to three weeks after birth the babies were played the same tunes, plus another one that had not been played in the womb. Video tapes were taken and assessed by two independent observers, who measured the "kick rates" of the babies.

The idea was to see if the music played to them in the womb soothed them and reduced the rate at which they kicked when compared either with silence or with the third tape. It did, and the music heard in the 21st week of pregnancy was as that heard in the 31st week.

Mr. Evans, who presented the results at the British Psychological Society annual conference in Brighton, said: "When you see the videos of the babies, there is a real contrast in their behavior. The babies who recognize the music look completely still and limp. The were extremely calm, very relaxed."

Earlier experiments showed that babies react to music played to them in the womb. But until now it had been thought that babies of less than 24 week gestation were incapable of memory because the cortex, the higher part of the brain, has not developed by this stage.

There were important implications, Mr. Evans said, for the way that babies might be affected by what was happening around them while in the womb. "If the mother is involved in a row, the fetus is hearing that at the same time as the mother. She has the hormonal changes that are associated with emotional conflict, and these hormones flood the fetus.

"If the fetus is aware at this time, it could result in a classical conditioned response later, after the baby is born. The baby could be frightened of its father's voice, associating it with the unpleasant memory."

He thought it might be a good idea for mothers to talk reassuringly to their unborn babies. But he said that it was a waste of time for expectant mothers to buy expensive attachments to place around their stomachs. "Music or the spoken word only needs to be as loud as background radio or stereo," he said.