The research, which was published in the journal Infant Behaviour & Development, suggests that babies begin to form memories and acquire knowledge earlier than previously thought. Previous research concluded that learning was able to take place at 37 weeks, but this study has found proof of learning up to three weeks sooner.
The researchers used the 'cardiac orienting response,' a small change in heart rate, to determine when a fetus remembered. This response is believed to be a response to a stimulus, and many believe it can be used to determine whether learning has taken place.
During the study, pregnant mothers were asked to read aloud an unfamiliar nursery rhyme twice a day between weeks 28 and 34 of the pregnancy. The participants were invited in for testing at 28, 32, 33, 34, 36 and 38 weeks of pregnancy. The testing was to determine whether the fetus recognized the nursery rhyme.
In order to be sure, a recording of an unfamiliar woman reading the nursery rhyme was played during testing. This was done to make sure the baby was not simply reacting to the familiar sound of the mother's voice. If the heart rate slowed, this was taken as proof that the baby recognized the words being spoken.
At 34 weeks, participants were told not to repeat the nursery rhyme again, in order to identify how long the memory lasted. Testing found that by 34 weeks, the babies began to respond to the nursery rhyme. This response continued during testing until around 38 weeks, or four weeks after the mother-to-be stopped reading the nursery rhyme aloud each day.
A control group was used to give a clearer understanding of fetal memory. In the control group testing, a recording of a woman reading a new nursery rhyme was played. The researchers found that the heart rates of these babies accelerated in response to the new rhyme.
This research gives a greater understanding of early learning and memory. It is hoped that it will influence how preterm babies are cared for. The more research we have about the womb environment, the more we can aid preterm babies. This research might help us understand how the mother's voice could be used to stimulate preterm infants.