Christine Moon

Two-day-olds prefer their native language

Newborn infants whose mothers were monolingual speakers of Spanish or English were tested with audio recordings of female strangers speaking either Spanish or English. Infant sucking controlled the presentation of auditory stimuli. Infants activated recordings of their native language for longer periods than the foreign language.

Language experienced in utero affects vowel perception after birth: a two-country study

To test the hypothesis that exposure to ambient language in the womb alters phonetic perception shortly after birth. This two‐country study aimed to see whether neonates demonstrated prenatal learning by how they responded to vowels in a category from their native language and another non‐native language, regardless of how much postnatal experience the infants had.

The role of mother's voice in the organization of brain function in the newborn

Newborn infants prefer the sound of the maternal voice within the first two days after birth. This early preference may be based on prenatal experience. The mothers voice is reported to be the most intense acoustical signal measured in the amniotic environment. Data showing the ability of the newborn to demonstrate voice preferences are presented. We have also investigated the response of the perinatal autonomic nervous system to speech sound stimulation. Both the newborn and fetus show heart rate decelerations in response to speech sounds. This cardiorespiratory attentional response occurs during sleep when sensory stimulation is probably influencing perinatal brain development. Early experience with voice has both acute and enduring effects on the developing brain. These effects have ramifications for the development of the auditory system, as well as for later social and emotional development. Further speculation and discussion on the form, function and assessment of newborn responsiveness to voice will be offered.

Evidence of transnatal auditory learning.

There is converging evidence for fetal retention of auditory experience into early postnatal life, but critical tests with appropriate controls are rare due to methodological hurdles. Research has been conducted on newborn response to naturally occurring stimuli such as heartbeats, intrauterine recordings, pre- and postnatal versions of the maternal voice, fathers voice, and unfamiliar voices. Postnatal experience cannot be ruled out as a possible explanation for many results. Only one critical prenatal exposure experiment with postnatal testing has been carried out and published in a peer-reviewed scientific journal. Interpretation of acoustic and linguistic information on intrauterine recordings suggests that the prosodic features of speech (pitch contours, rhythm, and stress) are available to the fetus. This is compatible with newborn responses and may contribute to language acquisition during the first year. There is no sound evidence that providing extra prenatal auditory stimulation benefits the developing child, and there are potential risks.

Canonical and Non-Canonical Syllable Discrimination by Two-Day-Old Infants.

Canonical syllables may be important units in early speech perception as well as production. Twenty infants (mean age 51 hours) (and twenty controls) were tested for their ability to discriminate between members of syllable pairs which were either canonical (paet and taep) or non-canonical (pst and tsp). A discrimination learning method was used in which syllables signalled the availability of either a recording of the mothers voice or silence--one of which was presented if the infant began a sucking burst. Infants in the canonical condition changed sucking patterns during signals over an 18-minute experimental session and activated their mothers voice more than silence, consistent with previous experiments using mothers voice as a reinforcer. In the non-canonical condition, infants also changed sucking patterns but sucked more during the signal for quiet than mothers voice, contrary to previous findings. Differential sucking during the syllables indicated discrimination in both conditions, but infants responded differently depending upon whether the syllables were canonical or non-canonical. The activation of silence in the non-canonical condition may be the result of a preference for quiet, but it is better explained as a failure to progress to a level of differential responding that was reached by the canonical group.

Mothers say “baby” and their newborns do not choose to listen: a behavioral preference study to compare with ERP results

Previously published results from neonatal brain evoked response potential (ERP) experiments revealed different brain responses to the single word “baby” depending on whether it was recorded by the mother or an unfamiliar female. These results are consistent with behavioral preference studies in which infants altered pacifier sucking to contingently activate recordings of the maternal vs. an unfamiliar female voice, but the speech samples were much longer and information-rich than in the ERP studies. Both types of neonatal voice recognition studies imply postnatal retention of prenatal learning. The preference studies require infant motor and motivation systems to mount a response in addition to voice recognition. The current contingent sucking preference study was designed to test neonatal motivation to alter behavior when the reward is the single word “baby” recorded by the mother or an unfamiliar speaker. Results showed an absent or weak contingent sucking response to the brief maternal voice sample, and they demonstrate the complementary value of electrophysiological and behavioral studies for very early development. Neonates can apparently recognize the maternal voice in brief recorded sample (previous ERP results) but they are not sufficiently motivated by it to alter sucking behavior.

Prenatal Experience with the Maternal Voice

Research studies over the past 40 years have established that the maternal voice is a prominent feature of the prenatal environment, that the fetus responds to it, and that prenatal learning carries over into early postnatal life. The primary aim of the chapter is to describe what is known through research about prenatal exposure to the mother’s voice, especially through audition. A second aim is to present a consideration of nonauditory experience such as the vestibular and, possibly, cutaneous sensations that are uniquely linked to auditory stimulation by the maternal voice. A third aim is to raise a question about the necessity of prenatal experience with the acoustic aspects of the maternal voice, given emerging data from deaf infants who receive cochlear implants many months after birth. The chapter concludes by considering implications for the care of hospitalized preterm infants who experience atypical experience with the mother’s voice and other sounds. Chapter conclusions are (1) fetal auditory experience with the mother’s voice begins around 24 weeks after conception, (2) the maternal voice is potentially a rich source of multimodal stimulation and information, and (3) for favorable postnatal development, the role that is played by very early exposure to the maternal voice is not yet understood.

Phonetic learning in utero.

The prevailing view is that newborn phonetic perception is tabula rasa because of poor transmission of the acoustic features of phonemes to the fetus. However, vowel information may be at least intermittently clear in utero. We tested 80 neonates (M = 32.8 h old, range 7–75) in the US and Sweden with English and Swedish vowels using an infant‐controlled sucking procedure. Sucking activated 1 of 17 stimuli (a prototype and 16 variants) from the same vowel category, either the English /i/ or the Swedish /y/. Infants sampled through all 17 stimuli, presented randomly, one time. The dependent measure was mean number of sucks per stimulus. Results showed that the Foreign Vowel Group had significantly greater means to the prototype than the Native Group. A within‐group analysis showed another Foreign‐Native Group difference. Infants in the Foreign Group had significantly more sucks to the prototype compared to the variants, whereas the Native Group treated the prototype and variants equivalently. These results ...

Newborn infant perception of vowels is affected by ambient language.

Behavioral research has shown that by 6 months of age, infants show an effect of experience with native language vowels. In a previous study of category organization, infants in Sweden and the United States treated a vowel prototype as equivalent to variants of the vowel in the native, but not the non‐native language. In the current behavioral study of Swedish and U.S. neonates, results were consistent with those of the 6‐month‐olds. Eighty infants (M=32.8 h since birth) in Washington State and Stockholm participated in a procedure in which non‐nutritive sucking activated one of 17 stimuli (a prototype and 16 variants) from the same vowel category. Twenty infants in each country heard their native vowel, and 20 the non‐native vowel. The vowels were English /i/ and Swedish /y/. Stimuli were serially and randomly activated by the onset of a sucking bout, and once a stimulus was activated, frequency of presentation was infant‐controlled. The dependent measure was number of sucks for each stimulus. For the no...