Months before their first words, babies' brains rehearse speech mechanics

July 14, 2014, University of Washington
A year-old baby sits in a brain scanner, called magnetoencephalography -- a noninvasive approach to measuring brain activity. The baby listens to speech sounds like "da" and "ta" played over headphones while researchers record her brain responses. Credit: Institute for Learning & Brain Sciences at the University of Washington

Infants can tell the difference between sounds of all languages until about 8 months of age when their brains start to focus only on the sounds they hear around them. It's been unclear how this transition occurs, but social interactions and caregivers' use of exaggerated "parentese" style of speech seem to help.

University of Washington research in 7- and 11-month-old infants shows that stimulate areas of the brain that coordinate and plan motor movements for speech.

The study, published July 14 in the Proceedings of the National Academy of Sciences, suggests that baby brains start laying down the groundwork of how to form words long before they actually begin to speak, and this may affect the developmental transition.

"Most babies babble by 7 months, but don't utter their first words until after their first birthdays," said lead author Patricia Kuhl, who is the co-director of the UW's Institute for Learning and Brain Sciences. "Finding activation in motor areas of the brain when infants are simply listening is significant, because it means the baby brain is engaged in trying to talk back right from the start and suggests that 7-month-olds' brains are already trying to figure out how to make the right movements that will produce words."

Kuhl and her research team believe this practice at motor planning contributes to the transition when infants become more sensitive to their native language.

The results emphasize the importance of talking to kids during social interactions even if they aren't talking back yet.

"Hearing us talk exercises the action areas of infants' brains, going beyond what we thought happens when we talk to them," Kuhl said. "Infants' brains are preparing them to act on the world by practicing how to speak before they actually say a word."

In the experiment, infants sat in a brain scanner that measures through a noninvasive technique called magnetoencephalography. Nicknamed MEG, the brain scanner resembles an egg-shaped vintage hair dryer and is completely safe for infants. The Institute for Learning and Brain Sciences was the first in the world to use such a tool to study babies while they engaged in a task.

Here's a video of one the babies in the experiment:

The babies, 57 7- and 11- or 12-month-olds, each listened to a series of native and foreign language syllables such as "da" and "ta" as researchers recorded brain responses. They listened to sounds from English and Spanish.

The researchers observed brain activity in an auditory area of the brain called the superior temporal gyrus, as well as in Broca's area and the cerebellum, cortical regions responsible for planning the motor movements required for producing speech.

This pattern of brain activation occurred for sounds in the 7-month-olds' native language (English) as well as in a non-native language (Spanish), showing that at this early age infants are responding to all speech sounds, whether or not they have heard the sounds before.

In the older infants, brain activation was different. By 11-12 months, infants' brains increase motor activation to the non-native speech sounds relative to native speech, which the researchers interpret as showing that it takes more effort for the baby brain to predict which movements create non-native speech. This reflects an effect of experience between 7 and 11 months, and suggests that activation in motor areas is contributing to the transition in early speech perception.

The study has social implications, suggesting that the slow and exaggerated parentese – "Hiiiii! How are youuuuu?" – may actually prompt infants to try to synthesize utterances themselves and imitate what they heard, uttering something like "Ahhh bah bah baaah."

"Parentese is very exaggerated, and when hear it, their brains may find it easier to model the motor movements necessary to speak," Kuhl said.

Explore further: While in womb, babies begin learning language from their mothers

More information: Infants' brain responses to speech suggest Analysis by Synthesis, PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1410963111

Related Stories

While in womb, babies begin learning language from their mothers

January 2, 2013
Babies only hours old are able to differentiate between sounds from their native language and a foreign language, scientists have discovered. The study indicates that babies begin absorbing language while still in the womb, ...

Babbling babies—responding to one-on-one 'baby talk'—master more words

January 6, 2014
Common advice to new parents is that the more words babies hear the faster their vocabulary grows. Now new findings show that what spurs early language development isn't so much the quantity of words as the style of speech ...

Study links bilingual babies' vocabulary to early brain differentiation

August 29, 2011
Babies and children are whizzes at learning a second language, but that ability begins to fade as early as their first birthdays.

Touch influences how infants learn language

April 23, 2014
(Medical Xpress)—Tickling a baby's toes may be cute but it's also possible that those touches could help babies learn the words in their language. Research from Purdue University shows that a caregiver's touch could help ...

Infants benefit from implants with more frequency sounds

May 19, 2014
(Medical Xpress)—A new study from a UT Dallas researcher demonstrates the importance of considering developmental differences when creating programs for cochlear implants in infants.

Babies may remember words heard before birth, research finds

August 26, 2013
(HealthDay)—If you feel like talking to your fetus in the womb, a new study suggests you should: The research finds that babies develop a memory of words they hear frequently before they are born.

Recommended for you

Research reveals atomic-level changes in ALS-linked protein

January 18, 2018
For the first time, researchers have described atom-by-atom changes in a family of proteins linked to amyotrophic lateral sclerosis (ALS), a group of brain disorders known as frontotemporal dementia and degenerative diseases ...

Fragile X finding shows normal neurons that interact poorly

January 18, 2018
Neurons in mice afflicted with the genetic defect that causes Fragile X syndrome (FXS) appear similar to those in healthy mice, but these neurons fail to interact normally, resulting in the long-known cognitive impairments, ...

How your brain remembers what you had for dinner last night

January 17, 2018
Confirming earlier computational models, researchers at University of California San Diego and UC San Diego School of Medicine, with colleagues in Arizona and Louisiana, report that episodic memories are encoded in the hippocampus ...

Recording a thought's fleeting trip through the brain

January 17, 2018
University of California, Berkeley neuroscientists have tracked the progress of a thought through the brain, showing clearly how the prefrontal cortex at the front of the brain coordinates activity to help us act in response ...

Midbrain 'start neurons' control whether we walk or run

January 17, 2018
Locomotion comprises the most fundamental movements we perform. It is a complex sequence from initiating the first step, to stopping when we reach our goal. At the same time, locomotion is executed at different speeds to ...

Miles Davis is not Mozart: The brains of jazz and classical pianists work differently

January 16, 2018
Keith Jarret, world-famous jazz pianist, once answered in an interview when asked if he would ever be interested in doing a concert where he would play both jazz and classical music: "No, that's hilarious. [...] It's like ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

russell_russell
not rated yet Jul 15, 2014
Infants can tell the difference between sounds of all languages until about 8 months of age when their brains start to focus only on the sounds they hear around them.


The difference between the sounds of all languages was not available as a source from which all infants "can tell the difference between" until about 8 months of age?

What was the focus on of all infants until about 8 months of age?
All infants can "tell the difference" until about 8 months of age.
What was the source of sound giving all infants the ability, acquisition, or capability to "tell the difference" between the "sounds of all languages" in the absent of all the "sounds of all languages" until about 8 months of age?

Reading further...
"...infants are responding to all speech sounds, whether or not they have heard the sounds before."

How is a response conditioned to a sound never heard before or for the first time?

Actually all these questions are answered during fetal development - before birth.
russell_russell
not rated yet Jul 15, 2014
A.
All infants basilar membranes at birth are organized tonotopically the same.
External auditory stimuli will eventually strengthen those signal pathways to an auditory area of the brain most often used to process the sounds coming from the surroundings the infants are exposed to after birth the most.

A pathway's strength (myelination) will eventually determined the sensitivity and selectivity of sounds heard more often externally.

Sensitivity and selectivity are reduce for pathways not undergoing heavy myelination (from lack of use) - stemming from sounds least heard. Becoming noticeable at about 8 months.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.