Summary: Baby talk can teach infants the relevant properties of language, a new study reports.
Many experts on infant learning have suggested that the best way to teach adult language to a tiny baby is to speak as if the infant is another adult – because adult sounds, cadence and tone of voice are what the child is eventually supposed to learn. But newly published research using mathematical models finds the best way to help a baby learn might actually be to follow many parents’ instincts and use “motherese,” a sing-songy voice that exaggerates the sounds the baby hears.
“Our intuitions are surprisingly right,” says Patrick Shafto, an associate professor of mathematics and computer science at Rutgers University-Newark (RU-N), who conducted the research – which is published in Psychological Review – with postdoctoral fellow Baxter Eaves. “Why do we speak funny to children? It’s actually to help them learn the relevant properties of language.”
Shafto, Eaves and colleagues deconstructed vowel sounds in adult speech. They then created a mathematical model that predicted understandable speech patterns from scratch, “to show what it might look like if speech were designed to actually teach children.” They then compared their invented teaching pattern with the differing speech methods that adults direct at each other and at infants, and found that infant-directed speech was the closer match.
“The sounds that are selected exaggerate the important properties that babies need to attend to and learn about,” Shafto says. “If you exaggerate in the correct way, what you get is a learner who learns more quickly from less data.” It makes sense to Shafto that over time the baby’s brain is then able to process the “motherese” into regular language.
Shafto, who also is Henry Rutgers Term Chair in computer science and on the faculty of RU-N’s College of Arts and Sciences, says his mathematical model is an elegant way to think about infants’ learning. This work, he cautions, is also preliminary. For instance, proving that infant-directed speech is more educational is difficult by definition because babies not even a year old are too young to speak, so it is challenging to probe any language skills they have learned.
But there may be a different group of learners who could demonstrate the value of a mathematical learning model. Shafto says American adults don’t only speak in exaggerated ways to infants. They also distort their speech with pets and with foreign language speakers – but they do it differently for each. Pets hear sing-songy voices with no effort by the speaker to exaggerate vowels to make the animals understand – a pure play to cuteness that differs from speech intended to teach a baby. Foreigners get the opposite – no condescending sing-song, but a concerted effort to exaggerate vowel sounds – the better to help the listener understand a language he or she doesn’t know.
Because foreign language speakers’ learning of English can be measured, Shafto says it might be possible to use mathematics to fine tune the speech patterns of instructors in ways that enhance the teaching of English as a second language. “By manipulating only the things that are important and highlighting the meaningful distinctions in the language,” he says, “we might be able to make English more learnable for someone who speaks a different language natively.”
According to Shafto, the bottom line of this new study, and of the work he is doing, is that math and the study of language learning go extremely well together. “Learning these vowel categories is a complicated problem,” he says. “There are lots of moving parts, so it’s not the sort of thing that one can easily intuit.”
“I think it’s a nice example of why mathematical rigor is important in areas where you least expect it,” Shafto adds, “such as understanding why we talk silly to children.”
About this neuroscience opinion article
Source: Robert Forman – Rutgers Image Source: This NeuroscienceNews.com image is in the public domain. Original Research:Abstract for “Infant-Directed Speech Is Consistent With Teaching” by Eaves Jr., Baxter S.; Feldman, Naomi H.; Griffiths, Thomas L.; and Shafto, Patrick in Psychological Review. Published online April 18 2016 doi:10.1037/rev0000031
[cbtabs][cbtab title=”MLA”]Rutgers. “Baby Talk May Be More Educational For Infants Than Imagined.” NeuroscienceNews. NeuroscienceNews, 27 June 2016. <https://neurosciencenews.com/baby-talk-linguistics-learning-4573/>.[/cbtab][cbtab title=”APA”]Rutgers. (2016, June 27). Baby Talk May Be More Educational For Infants Than Imagined. NeuroscienceNews. Retrieved June 27, 2016 from https://neurosciencenews.com/baby-talk-linguistics-learning-4573/[/cbtab][cbtab title=”Chicago”]Rutgers. “Baby Talk May Be More Educational For Infants Than Imagined.” https://neurosciencenews.com/baby-talk-linguistics-learning-4573/ (accessed June 27, 2016).[/cbtab][/cbtabs]
Infant-Directed Speech Is Consistent With Teaching
Infant-directed speech (IDS) has distinctive properties that differ from adult-directed speech (ADS). Why it has these properties—and whether they are intended to facilitate language learning—is a matter of contention. We argue that much of this disagreement stems from lack of a formal, guiding theory of how phonetic categories should best be taught to infantlike learners. In the absence of such a theory, researchers have relied on intuitions about learning to guide the argument. We use a formal theory of teaching, validated through experiments in other domains, as the basis for a detailed analysis of whether IDS is well designed for teaching phonetic categories. Using the theory, we generate ideal data for teaching phonetic categories in English. We qualitatively compare the simulated teaching data with human IDS, finding that the teaching data exhibit many features of IDS, including some that have been taken as evidence IDS is not for teaching. The simulated data reveal potential pitfalls for experimentalists exploring the role of IDS in language learning. Focusing on different formants and phoneme sets leads to different conclusions, and the benefit of the teaching data to learners is not apparent until a sufficient number of examples have been provided. Finally, we investigate transfer of IDS to learning ADS. The teaching data improve classification of ADS data but only for the learner they were generated to teach, not universally across all classes of learners. This research offers a theoretically grounded framework that empowers experimentalists to systematically evaluate whether IDS is for teaching.
“Infant-Directed Speech Is Consistent With Teaching” by Eaves Jr., Baxter S.; Feldman, Naomi H.; Griffiths, Thomas L.; and Shafto, Patrick in Psychological Review. Published online April 18 2016 doi:10.1037/rev0000031