Babies love baby talk all over the world, says Michael Frank, the Stanford psychologist behind the largest study to date looking at how infants from across the world respond to the different ways adults speak.
The study, published March 16 in the journal Advances in Methods and Practices in Psychological Science, tested 2,329 babies from 16 countries on their preference for baby talk, the sing-songy, high-pitched way that adults often naturally talk to small children.
And the results are in: Little ones prefer it when grownups “ooh” and “coo.”
“Overall, babies from every site preferred baby talk,” said Frank, the David and Lucile Packard Professor of Human Biology in the School of Humanities and Sciences.
The researchers found that older babies preferred baby talk more than younger infants, and infants of all ages preferred baby talk when it was uttered in their native language – probably because that’s what they recognize, said Frank.
“Often parents are discouraged from using baby talk by well-meaning friends or even health professionals,” Frank said.
“But the evidence suggests that it’s actually a great way to engage with your baby because babies just like it—it tells them, “This speech is meant for you!'”
Studying baby talk
While it was known from previous research that babies prefer baby talk over adult speech, Frank wanted to know whether this finding would vary across cultures and continents.
“Different cultures around the world baby talk more and less to their kids,” said Frank. “Do babies who hear less baby talk like it less or not at all?”
Often, however, researchers draw universal conclusions from studies at one university with only a few dozen babies. Frank didn’t want to fall into this trap. So, he thought bigger.
“We wanted to get labs together from around the world to test how similar or different babies’ preferences are across different environments,” Frank said.
Through the “ManyBabies” Project-an international research consortium Frank co-founded in 2015 – a team of 67 labs in North America, Europe, Australia and Asia were assembled (collaborations to test babies in Africa and South America are underway).
The average age of infants in the study was about nine months, with some as young as three months and as mature as 15 months.
Each lab followed the same experimental parameters, tested the same phenomena and used the same stimuli, specifically audio clips of other mothers speaking in baby talk to their infants and mothers talking normally to an adult in North American English.
Overall, the researchers found that babies preferred clips of mothers talking to their baby.
The preference for this childish chit-chat was also stronger when the speech patterns matched an infants’ native language – showing that their prior exposure to baby talk at home mattered, said Frank.
“We think babies’ preferences probably come partly from their experience with baby talk at home, but also partly because more melodic speech just sounds nicer to them,” said Frank.
Coming together to solve research questions
While researchers all tested the same question with the same recordings, different labs did the procedure slightly differently. This gave Frank and his collaborators an opportunity to determine which method gave the best measurements.
For example, they found that one of the methods they used called the “head-turn preference procedure” – which trains babies to turn their head to one side to hear baby talk and the other side to hear adult talk – resulted in the most effective measurement.
“Findings like this one can really help other labs choosing their experimental method down the road, illustrating why it’s important to team up the way we did in this study,” said Frank.
Parental language input is one of the best predictors of children’s language achievement. Parentese, a near-universal speaking style distinguished by higher pitch, slower tempo, and exaggerated intonation, has been documented in speech directed toward young children in many countries.
Previous research shows that the use of parentese and parent–child turn-taking are both associated with advances in children’s language learning. We conducted a randomized controlled trial to determine whether a parent coaching intervention delivered when the infants are 6, 10, and 14 mo of age can enhance parental language input and whether this, in turn, changes the trajectory of child language development between 6 and 18 mo of age.
Families of typically developing 6-mo-old infants (n = 71) were randomly assigned to intervention and control groups. Naturalistic first-person audio recordings of the infants’ home language environment and vocalizations were recorded when the infants were 6, 10, 14, and 18 mo of age.
After the 6-, 10-, and 14-mo recordings, intervention, but not control parents attended individual coaching appointments to receive linguistic feedback, listen to language input in their own recordings, and discuss age-appropriate activities that promote language growth.
Intervention significantly enhanced parental use of parentese and parent–child turn-taking between 6 and 18 mo. Increases in both variables were significantly correlated with children’s language growth during the same period, and children’s language outcomes at 18 mo. Using parentese, a socially and linguistically enhanced speaking style, improves children’s social language turn-taking and language skills. Research-based interventions targeting social aspects of parent–child interactions can enhance language outcomes.
The present study was designed to test three specific hypotheses: That a parent coaching intervention delivered at 6, 10, and 14 mo would:
1) Increase parental use of parentese speech, but not parental use of standard speech, or the overall quantity of parental speech;
2) increase parent–child turn-taking between 6 and 18 mo; and
3) lead to enhanced growth in child vocalizations during the same time period, and enhanced language outcomes at 18 mo, 4 mo after the third coaching appointment.
The results support our hypotheses. Parents who received coaching increased their use of parentese and were engaged with their child in more conversational turns compared to parents who did not receive coaching.
Their children, in turn, increased their production of speech-related vocalizations significantly more between 6 and 18 mo, and produced more words at 18 mo.
Importantly, the growth in parentese and turn-taking between 6 and 18 mo was positively correlated with the growth in children’s vocalizations during the same time period and with children’s 18-mo language outcomes, suggesting that parental and child language behaviors coevolved.
We have previously shown that parentese can be enhanced by parent coaching, and that this has immediate effects on child language (30). The data presented here further support the notion that experimental manipulation of parental language input is possible, across a range of SES backgrounds.
We show that enhancements in parental social communication skills are both robust and durable, and suggest that the effects of parent coaching between 6 and 18 mo put both parents and children on a trajectory of enhanced social communication, evidenced by an increase in conversational turn-taking that we measured in the I group.
As such, we argue that the present study presents evidence for a social benefit of parentese. It should be noted that the present study measured the effects of the intervention on a predetermined set of social interaction and child language variables.
It is, of course, possible that the intervention changed other parental and child behaviors that were not assessed here. It should also be noted that the present study focuses on young children in the early stages of productive speech.
Previous research shows that some aspects of parental input may relate more to child language development at different developmental stages than others (40), and future studies should investigate the importance of parentese and other social aspects of parental speech at later ages.
However, previous research also indicates that differences in language skills in infancy are predictive of subsequent stages in language development (36, 51, 54, 55), and suggests that enhancement in parental social behaviors achieved through intervention could have cascading effects on infant speech development over time.
Follow-up studies should assess children’s language skills with objective language measures in the laboratory, as well as assess children’s language-related brain function and structure, to monitor the potential effects of interventions in infancy on long-term language, cognitive, and neural outcomes.
Previous studies demonstrate that, while parents may know that talking with their child promotes language learning, they are rarely aware of the specific aspects of their own language behaviors (46, 47, 53).
Although all families in the present sample already used parentese at baseline, conversation during the coaching appointments revealed that the vast majority of parents were unaware of its positive effects on children’s language growth, struggled to name specific moments of the day when they use parentese, and were often surprised to hear themselves using it in the recordings.
Our approach was to raise their awareness by highlighting the research behind parentese and other social aspects of parent–child interactions, and by demonstrating to parents, through listening to their own recordings, that they can interact with their infant in ways that promote language growth.
We provided qualitative and quantitative linguistic feedback, and explained how and why each language measure can vary from day to day, from family to family, and from context to context. Finally, we gave parents concrete language tips and, through discussion of their own daily routines, encouraged them to think of additional scenarios in which they can use language and interact with their infant.
Parents were generally grateful to leave the appointments with new ideas to implement at home. The results presented here support the notion that complex scientific information can successfully be explained to nonscientists (parents) to leverage their use of specific language behaviors and have a powerful effect on children’s learning (56).
While the findings described here apply to a broad range of SES backgrounds, it remains to be seen how they generalize to other populations, such as bi/multilingual families, clinical populations, or cultures where parent–child verbal interaction is limited (57).
The present study illuminates the debate about the specific mechanisms by which parentese enhances children’s language growth. With its dramatic changes in the pitch of the voice (10), as well as exaggerated facial movements (58), parentese conveys a positive emotion that makes the speaker sound “happy” (29, 59).
Furthermore, we established here that both parentese and conversational turns are related to enhanced language growth, which adds to the growing body of work linking language learning to social processes.
The importance of a social context in language learning was demonstrated earlier in studies of foreign-language exposure at 9 mo of age, a “sensitive period” in phonetic learning (61).
In the original study, infants experienced a foreign language while interacting socially with live tutors as opposed to receiving the identical language input delivered via video (61). Results demonstrated that live social interaction resulted in rapid and robust learning of the sounds that was equivalent to that of 9-mo-olds living in the foreign country, but that exposure via video produced no learning whatsoever (61).
Analysis of the social (eye gaze) behaviors during these interactions were positively related to neural measures of phoneme and word learning, and infants’ attention in the live, interactive social settings was higher than when watching the same material via video (61), suggesting that social skills play a critical role in language learning (62).
The social interaction promoted by parentese has been relatively neglected as a cause of increased language learning in favor of explanations that parentese enhances learning because it enriches the linguistic signal (14).
Contingency or reciprocity in parents’ reactions to children’s vocalization increases their complexity (65), which is consistent with our previous data demonstrating that the parent intervention increased concurrent infant babbling, itself a positive predictor of the child’s future language (30).
Through back and forth exchanges, parents provide contingent feedback that is constantly adjusted to their infants’ linguistic needs, and infants, in turn, adjust their vocalizations in response to parental vocalizations (66–69), thereby creating a positive feedback loop (70).
Early language learning depends on infants’ social interest in the people around them, their appreciation of others’ communicative intentions, and their desire to engage with adults through imitation (42, 71).
Studies using advanced neuroimaging in the form of magnetoencephalography reveal an auditory–motor link that is activated as infants listen to speech: Auditory presentations of speech activate speech motor planning areas, such as Broca’s area and the cerebellum that allow infants to respond with their own vocalizations as early as 7 mo of age (72).
The acoustic and visual features of parentese may represent an ideal signal both linguistically and socially that activates the social brain systems underlying infants’ motivation to learn language (60, 72, 73).
Research on children aged 4 to 6 y demonstrates that the number of conversational turns during parent–child language interactions correlates positively with stronger more coherent white-matter track connectivity in the language areas of the brain, an effect independent of SES (74).
While further studies will be necessary to fully unpack the underlying mechanisms through which social language interaction enhances infant language development, the present study demonstrates that translational science can create successful interventions and has the potential to improve children’s language learning.
More information: undefined undefined. Quantifying Sources of Variability in Infancy Research Using the Infant-Directed-Speech Preference, Advances in Methods and Practices in Psychological Science (2020). DOI: 10.1177/2515245919900809