Scientists already know that human foetuses begin to notice sounds coming from outside of the womb by around the 27th week of pregnancy.
But what wasn't known was whether they can learn from these sounds as part of their development.
To try to find out, researchers from the Cognitive Brain Research Unit at the Institute of Behavioral Sciences, University of Helsinki in Finland followed 33 pregnant women from week 29 of pregnancy until they gave birth.
The families of the learning group were given a CD in which two 4-minute sequences consisting of three variants of a “tatata” sound were played. In each of the sequences, the standard “tɑtɑtɑ” was presented 429 times, a vowel change (tɑtotɑ) was presented 146 times, and different pitch changes in the middle syllable were presented 74 times. The mothers were instructed to play the CD 5-7 times per week, preferably at approximately the same time of day. To make listening more pleasant, sequences were interspersed with nonvocal music.
After the babies were born, they were all played the sounds again during brain scans. These scans suggest that the babies who'd heard the word in the womb remembered it and reacted to it.
Talk to the bump
Co-author of the study paper, Professor Minna Huotilainen, tells us by email: "We tried the formation with one single word 'tatata'. It doesn't mean anything, so it is a so-called pseudoword.
"This word was repeated in its original form, and in a few different ways of uttering the same word."
They then waited until the babies were born to see if they remembered the word: "After birth, we tested the brain responses for memory traces of the words heard before birth, and we found clear evidence that both the original 'tatata' was remembered, as well as the changed forms.
"In addition, we found that minor changes in the word 'tatata', like changing its pitch, duration or changing it to 'tatota' gave stronger and faster reactions in the brains of the infants who had been listening to the tape prior to birth."
The research team hasn't yet tried different sounds or songs to compare how well babies remember them. "Of course we want to continue to this direction," Professor Huotilainen says.
"Previously, in studies assessing the behaviour of infants, strong memory traces for simple songs have been shown. It may well be that singing creates very strong memories, but this needs to be confirmed."
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