NurtureShock (29 page)

The first time a mother and her infant arrive for an appointment at Michael Goldstein’s lab in the psychology building on
the Cornell University campus, they’re not tested at all. They’re simply put in a quiet room with a few toys, for half an
hour, to get used to the setting. The walls are white, decorated with Winnie the Pooh stickers. The carpet is light brown
and comfortable to sit on. On the floor are many of the same playthings the infant might have at home—a brightly colored stuffed
inchworm, stacking rings, a play mat with removable shapes, and a toy chest to explore. At three points around the room, videocameras
extend from the wall, draped in white cloth to be inconspicuous. The mom knows full well that she is being watched, both on
camera and through a large one-way glass pane. But this is otherwise a nice moment to interact with her baby—she can’t be
distracted by the cell phone or household chores. Her baby pulls himself to his mom’s lap, puts the toys nearby in his mouth,
and if he can crawl, perhaps pulls himself up to look inside the toy chest.

The next day, mother and baby return. In Goldstein’s seminal experiment, the nine-month-old infant is put in denim overalls
that carry a very sensitive wireless microphone in the chest pocket. The mother is given a pair of wireless headphones that
still allow her to hear her baby. They are put back in the playroom, and again asked to play together naturally. After ten
minutes, a researcher’s voice comes over the headphones with instructions. When the mom hears the prompt “Go ahead,” she’s
supposed to lean in even closer to her baby, pat or rub the child, and maybe give him a kiss.

The mom doesn’t know what triggers this cue. The mom just knows that, over the next ten minutes, she hears “Go ahead” a lot,
almost six times a minute. She might notice that her baby is vocalizing more—or that he’s waving his arms or flapping his
feet—but she won’t know what’s triggering this. For the final ten minutes, she’s asked to simply play and interact naturally
with her child again.

When mother and infant leave, she has almost no idea what the researchers might have been up to. For two half-hour periods,
she merely played and talked with her child.

But here’s what it was like on the other side of the one-way glass: during those middle ten minutes, every time the child
made a voiced sound (as opposed to a cough, grunt, or raspberry), it could be heard loudly over speakers in the observation
room. Immediately, the researcher told the mother to “go ahead,” and within a second the mother had affectionately touched
the child. Later that night, a graduate student would sit down with the session videotape and take notes, second by second,
tracking how often the baby babbled, and what quality of sounds he made.

While all baby babble might sound like gibberish, there’s actually a progression of overlapping stages, with each type of
babble more mature and advanced than the one prior. “No less than eighty muscles control the vocal tract, which takes a year
or more to gain control of,” Goldstein explained. From birth, children make “quasi-resonant” vowel sounds. They use the back
of the vocal tract with a closed throat and little breath support. Because the larynx hasn’t yet descended, what breath there
is passes through both the mouth and nose. The result is nasal and creaky, often sounding like the baby is fussy (which it’s
not).

While the child won’t be able to make the next-stage sound for several months, there’s still a very important interaction
with parents going on. They basically take turns “talking,” as if having a mock conversation. The baby coos, and the daddy
responds, “Is that so?” The baby babbles again, and the daddy in jest returns, “Well, we’ll have to ask Mom.”

While most parents seem to intuit their role in this turn-taking pattern spontaneously—without being told to do so by any
handbook—they don’t all do so equally well. A remarkable study of vocal turn-taking found that when four-month-old infants
and their parents exhibited better rhythmic coupling, those children would later have greater cognitive ability.

According to Goldstein, “Turn-taking is driving the vocal development—pushing the babies to make more sophisticated sounds.”

Parents find themselves talking to their baby in the singsongy cadence that’s termed “parentese,” without knowing why they’re
strangely compelled to do so. They’re still using English, but the emotional affect is giddily upbeat and the vowels are stretched,
with highly exaggerated pitch contours. It’s not cultural—it’s almost universal—and the phonetic qualities help children’s
brains discern discrete sounds.

Around five months, a baby has gained enough control of the muscles in the vocal tract to open her throat and push breath
through to occasionally produce “fully resonant” vowels. “To a mother of a five-month-old,” Goldstein said, “hearing a fully
resonant sound from her baby is a big deal. It’s very exciting.” If her response is well-timed, the child’s brain notices
the extra attention these new sounds win. At this point, parents start to phase out responding to all the old sounds, since
they’ve heard them so often. That selective responsiveness in turn further pushes the child toward more fully-resonant sounds.

Soon the baby is adding “marginal syllables,” consonant-vowel transitions—rather than “goo” and “coo,” more like “ba” and
“da,” using the articulators in the front of the mouth. However, the transition from the consonant to the vowel is drawn out,
since the tongue and teeth and upper cleft can’t get out of the way fast enough, causing the vowel to sound distorted. (This
is why so many of a baby’s first words start with
B
and
D
—those are the first proper consonants the muscles can make.)

As early as six months, but typically around nine months, infants start producing some “canonical syllables,” the basic components
of adult speech. The consonant-vowel transition is fast, and the breath is quick. The child is almost ready to combine syllables
into words. “We used nine-month-olds in our study because at that age, they are still commonly expressing all four types of
babble,” Goldstein said. Quasi-resonant vowel babble might still be in the majority, and canonical syllables quite rare.

With this developmental scale in mind, it’s shocking to hear the difference in how the baby vocalizes over the course of Goldstein’s
experiment. In the first ten minutes (that baseline natural period when the mom responded as she might at home), the average
child vocalized 25 times. The rate leapt to 55 times in the middle ten minutes, when the mom was being coached to “go ahead”
by Goldstein. The complexity and maturity of the babble also shot up dramatically; almost all vowels were now fully voiced,
and the syllable formation improved. Canonical syllables, previously infrequent, now were made half the time, on average.

To my ear, it was stunning—the children literally sounded five months older, during the second ten-minute period, than they
had in the first.

“What’s most important to note here is that the infant was not mimicking his parent’s sounds,” Goldstein noted.

During those middle ten minutes, the parent was only caressing the child, to reward the babble. The child wasn’t hearing much
out of his mother’s mouth. But the touching, by itself, had a remarkable effect on the frequency and maturity of the babble.

Goldstein reproduced the experiment, asking parents to speak to their children as well as touch them. Specifically, he told
half the parents what vowel sound to make, the other half he fed a consonant-vowel syllable that was wordlike, such as “dat.”
Not surprisingly, the tots who heard vowels uttered more vowels, and those who heard syllables made more canonical syllables.
Again though, the babies weren’t repeating the actual vowel or consonant-vowel. Instead, they adopted the phonological pattern.
Parents who said “ahh” might hear an “ee” or an “oo” from their baby, and those who said “dat” might hear “bem.” At this tender
age, infants aren’t yet attempting to parrot the actual sound a parent makes; they’re learning the consonant-vowel transitions,
which they will soon generalize to
all
words.

To some degree, Goldstein’s research seems to have unlocked the secret to learning to talk—he’s just given eager parents a
road map for how to fast-track their infants’ language development. But Goldstein is very careful to warn parents against
overdoing it. “Children need breaks for their brain to consolidate what it’s learned,” he points out. “Sometimes children
just need play time, alone, where they can babble to themselves.” He also cites a long trail of scholarship, back to B.F.
Skinner, on how intermittent rewards are ultimately more powerful than constant rewards.

And lest any parent pull her infant out of day care in order to ensure he’s being responded to enough, Goldstein says, “The
mix of responses a baby gets in a high-quality day care is probably ideal.”

Tamis-LeMonda also warns against overstimulation. Her moms weren’t responding at that high rate
all day.
“In my study, the mothers were told to sit down and play with their infant and these toys. But the same mom, when feeding
the baby, might respond only thirty percent of the time. When the child is playing on the floor while the mom is cooking,
it might be only ten percent. Reading books together, they’d have a very high response rate again.”

Goldstein has two other points of caution, for parents gung-ho on using his research to help their babies. His first concern
is that a parent, keen to improve his response rate, might make the mistake of over-reinforcing less-resonant sounds when
a baby is otherwise ready to progress, thereby slowing development. This would reward a baby for immature sounds, making it
too easy for the baby to get attention. The extent to which parents, in a natural setting, should phase out responses to immature
sounds, and become more selective in their response, is thus far unknown.

Goldstein’s second clarification comes from a study he co-authored with his partner at Cornell, Dr. Jennifer Schwade. As Goldstein’s
expertise is a tot’s first year of life, Schwade’s expertise is the second year, when children learn their first 300 words.
One of the ways parents help infants is by doing what’s called “object labeling”—telling them, “That’s your stroller,” “See
the flower?,” and “Look at the moon.” Babies learn better from object-labeling when the parent waits for the baby’s eyes to
naturally be gazing at the object. The technique is especially powerful when the infant both gazes
and
vocalizes, or gazes
and
points. Ideally, the parent isn’t intruding, or directing the child’s attention—instead he’s following the child’s lead.
When the parent times the label correctly, the child’s brain associates the sound with the object.

Parents screw this up in two ways. First, they intrude rather than let the child show some curiosity and interest first. Second,
they ignore what the child is looking at and instead take their cues from
what they think the child was trying to say
.

The baby, holding a spoon, might say “buh, buh,” and the zealous parent thinks, “He just said ‘bottle,’ he wants his bottle,”
and echoes to the child, “Bottle? You want your bottle? I’ll get you your bottle.” Inadvertently, the parent just crisscrossed
the baby, teaching him that a spoon is called “bottle.” Some parents, in Goldstein and Schwade’s research, make these mismatches
of speech 30% of the time. “Beh” gets mistaken by parents as “bottle,” “blanket,” or “brother.” “Deh” is interpreted as “Daddy”
or “dog,” “kih” as “kitty,” and “ebb” as “apple.” In fact, at nine months old, the baby may mean none of those—he’s just making
a canonical syllable.

Pretending the infant is saying words, when he can’t yet, can really cause problems.

Proper object-labeling, when the infants were nine months, had an extremely strong positive correlation (81%) with the child’s
vocabulary six months later. Crisscrossed labeling—such as saying “bottle” when the baby was holding a spoon—had an extremely
negative correlation with resulting vocabulary (–68%). In real life terms, what did this mean? The mother in Schwade’s study
who was best at object labeling had a fifteen-month-old daughter who understood 246 words and produced 64 words. By contrast,
the mother who crisscrossed her infant the most had a fifteen-month-old daughter who understood only 61 words and produced
only
5.