Your Baby Recognizes Your Voice In-Utero
Your baby likes you best
While previous research on infant development has demonstrated that newborns prefer to listen to their own mother's voice to that of a female stranger and will even change their behavior to elicit their mother's voice, Dr Kisilevsky's research proves that this "preference/recognition" begins before birth.
"This is an extremely exciting finding that provides evidence of sustained attention, memory and learning by the fetus," says Dr Kisilevsky. "The fetuses learn about their mother's voice in the womb and then prefer it after birth. Our findings provide evidence that in-utero experience has an impact on newborn/infant behavior and development, and that voice recognition may play a role in mother-infant attachment."
The findings also suggest that the foundation for speech perception and language acquisition are laid before birth, notes Dr Kisilevsky. Therefore, the precocious language processing abilities observed in newborns and young infants may not be due to a hardwired speech-processing module in the brain as has been assumed, but instead stems from the interaction of the fetus with its environment.
How they figured it out
Along with researchers at Zhejiang University, China, Dr Kisilevsky tested 60 fetuses at term. Thirty babies were played a two-minute audiotape of their own mother reading a poem, and another 30 babies were played the voice of a female stranger reading the poem. The researchers found that the little ones responded to their own mother's voice with heart-rate acceleration, and to the stranger's voice with a heart-rate deceleration. The responses lasted during the two-minute tape as well as for at least two minutes after the offset of the voices.
"These results tell us that the fetuses heard and responded to both voices and that there was sustained attention to both voices," notes Dr. Kisilevsky. "But, because they responded differently to the two voices, we know they had to recognize their own mother's voice. We believe they are probably already learning about language in general and their own language specifically."
Dr Kisilevsky's team is now investigating both fetal response to the father's voice and the ability of the fetus to differentiate between English and Mandarin. In 2000, her research team proved that babies hear by the third trimester of pregnancy.