Patricia Kuhl customarily opens her lectures with the same two slides: The first shows the stages of the development the human brain undergoes from birth until age 18. It’s plain to see that the most significant leap in development occurs in the first year, with a second surge taking place between the ages of 1 and 3. Subsequently the brain develops slowly until reaching its final size at maturity. With the slide lighting up her back, Prof. Kuhl, co-director of the Institute for Learning and Brain Sciences at the University of Washington in Seattle, looks at the audience and says, “If you were the decider and you had the money and you were the politician, where would you spend the money? When in development would you spend the money?” Naturally, everyone replies, “In the early stages” – that is, where there is the highest potential to effect changes in the brain.
The second slide is meant to demonstrate the importance of such an investment. It compares the vocabulary of infants from three socioeconomic classes in the United States, from birth to three years of age. All of them start with no vocabulary at all, of course, but by the age of 10 months, the three graphs veer apart sharply. Whereas children who grow up in families where parents have at least a high-school education can speak, on average, 1,200 words by age 3, children in working-class families have a vocabulary of 600 words, and children from families on welfare know only 300 words.
The disparities in vocabulary show that cognitive differences between children begin from the day they are born. By the time a child enters first grade, his brain will have grown to 90 percent of its final size. The brain of children born into educated families develops in an optimal way, whereas less fortunate youngsters will begin first grade with a vacuum, which schooling will probably never be able to fill. Accordingly, says Kuhl, government intervention on behalf of children must be launched as early as possible.
She isn’t just a talker, she’s a doer, an activist – which is a bit surprising because she is a brain researcher, not an educator per se. While you may have never heard her name before, you are probably aware of the implications of her studies, which resonate both among scientific communities and the public, around the world. A recipient of numerous prizes and honorary degrees, Kuhl, 73, is different from other scholars, whose research findings remain within the walls of ivory towers or in professional periodicals: She has made tireless efforts to convert discoveries in the lab she runs into policy on the ground, presenting her research to three presidents – Bill Clinton, George W. Bush and Barack Obama – and dozens of education ministers and other policy makers around the world. Her TED lecture has more than three million views. Her husband, child psychologist Andrew Meltzoff, is also a renowned expert on infant and child development. Their daughter, Katherine Kuhl-Meltzoff Stavropoulos, is a brain researcher who specializes in autism.
Kuhl recently visited Tel Aviv at the invitation of Urban95, a joint project of the Bernard van Leer Foundation, the Tel Aviv Foundation, Bloomberg Philanthropies and the Tel Aviv Municipality’s culture and sports administration. The “95” refers to the average height of a 3-year-old: 95 centimeters (37.4 inches). Tel Aviv is the first Israeli city to affiliate itself with the international project, which encourages urban planning and design intended to promote optimal development in early childhood. Underlying this undertaking is the belief that a short but critical window of opportunity for children exists during the first few years of life. Economics is also a factor: Studies show that every dollar invested in children during this period generates a return of between $7 and $10 in the future, in terms of economic productivity.
I met Kuhl at Tel Aviv City Hall, shortly after she spoke to municipal employees about the importance of cultivating brain development in infants. Her most recent research study, whose results are due to be published in a scientific journal, deals with the effect of a parent ignoring a baby because he or she is busy on the cellphone. This echoes the famous 1975 Still Face Experiment, conducted by developmental psychologist Edward Tronick. Tronick showed that when a mother’s face abruptly became indifferent and emotionless, after three minutes, the infant “rapidly sobers and grows wary. He makes repeated attempts to get the interaction into its usual reciprocal pattern. When these attempts fail, the infant withdraws [and] orients his face and body away from his mother with a withdrawn, hopeless facial expression,” as Tronick put it.
Kuhl’s research was similar, but she probed deeper into the brain of the infants. Moreover, instead of using as subjects parents who adopted a passive expression, the parents in her study turned their attention to their phones. She brought into her lab a magnetoencephalography (MEG) neuroimaging machine – which is used to map brain activity – that had been adapted for use with babies. It was the first time the technique, which registers the magnetic fields produced by electrical currents occurring naturally in the brain, had been used for infants responding to various stimuli.
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“It looks like a hair dryer from Mars, but it is totally safe,” Kuhl says. “Anyone of any age can sit in the machine,” and babies can move about as freely as they like.
During the experiment, Kuhl explains, “Mama is sitting next to the baby and she’s talking and mothering and playing and touching him” – and then, at a signal from the researcher the mother begins to look at the cellphone she’s holding, “and doesn’t respond to the baby. The baby’s brain response to that is very negative, the fear centers light up. You can see how strongly babies react to the absence of their parent’s attention, especially when it happens suddenly and unpredictably” – as it can in real life when the phone rings.
Kuhl has little good to say about electronic screens in general. And coming from her, that’s scary, because she knows very well what happens in a human brain.
“I worry about our dependence on screens,” she cautions. Our brain, she says, is most active and creative when it is not confronting a new task – when we are staring into space. “The screen is very tempting, but we are losing something by being so constantly driven by this thing, which keeps us constantly in a loop of getting work done.”
Her prognosis? We will reach a point when we can no longer tolerate screens individually or collectively, and only then will we start to look for equilibrium – the place where the screens still help us but do not cause our brains to atrophy, in a metaphorical sense.
Until that happens, she warmly recommends cutting ourselves off from the phone at our own initiative, in order to save the brain. In any case, it’s preferable not to put a toddler up to the age of 2 in front of a screen, because at that age children are still learning how to read and interpret facial expressions, and the screen blunts that process.
Though the issue of the screens is the focus of Kuhl’s research these days, she gained her renown from studying how infants learn. She is the person who informed the world that the part of the human brain that’s responsible for communication, the forging of friendships and emotions (what is considered the left side of the brain) is eternally connected to the cognitive region (the right side of the brain), which is responsible for learning.
“The social brain is the gateway to cognitive learning,” she says. “Ten years ago, social information, music and other artistic endeavors were considered to originate on the right side of the brain; whereas logic and language and mathematics were considered to belong to the left side. This is totally incorrect. All sections of the brain are involved very strongly in the learning process. The social and attention and engagement centers of the brain are absolutely key to cognitive learning – it’s artificial to separate them.” Kuhl came to this conclusion through her research into language-learning skills. In one study, English-speaking American parents came to her laboratory with their 6-month-old infants for a session of playing, singing and storytelling – but in Mandarin Chinese, the language of one of her doctoral students. This was repeated once a week for 12 weeks. In the meetings, the student played with the babies, sang to them and played musical instruments, all the while speaking Mandarin. There was also a parallel control group in English. At the end of the series, the children who had been exposed to Chinese responded to it and understood it exactly like children for whom it was the mother tongue.
All this linguistic bounty emanated from 12 one-hour encounters. The reason for the phenomenal success is that they took place during the magical window of opportunity, as Kuhl terms the period between four months and eight months. At that age, she says, a language can be learned with astonishing speed and naturalness.
The next stage of the research she conducted is even more fascinating. In the United States, Kuhl relates, there’s a glut of computer programs, television shows and apps that claim to be able to teach infants and children a second language. Kuhl decided to check whether the unequivocal findings of the Mandarin Chinese experiment would hold also when the little ones learned that language via a screen. The doctoral student repeated what she had done with the infants in the previous experiment, only this time not in person. Instead, her face was seen on a television screen, or only her voice was heard. The findings will disappoint anyone who pins hopes on such programs. The infants looked at the screen with interest, touched it and were curious about it, but after 12 encounters – visual and aural – it was obvious that they hadn’t learned Mandarin Chinese at all.
Kuhl’s explanation is that only when a person is physically next to an infant does the social region of his or her brain activates the cognitive region, which performs learning – in this case, language acquisition.
'So much fun'
Kuhl had intended to become a research physician and focus on brain damage among adults who suffer a stroke. A year into her doctoral studies at the University of Minnesota, her supervisor died and she was unable to find anyone else who specialized in language loss. Another teacher at the university suggested that she investigate language development in infants, an area that had not been studied until then in neurological terms.
“It wasn’t much of a field,” Kuhl recalls, “because there weren’t really brain studies, no brain images at all, and very little was known about the mind and brain of the child. So everything you did was huge. You’re constantly pulling yourself up in amazement about the things you would learn. It’s just been so much fun.”
The pleasure Kuhl derives from her work is palpable. She declares that to her last day, she will study infants and work for their benefit. Say the words “second language” to Kuhl and you unleash an abundance of information, including a description of an experiment involving a conundrum that 11-month-olds were supposed to solve. A baby sits in his mother’s lap, and opposite them a pleasant, smiling tester. The tester shows the baby a noisy, alluring toy, then places it in a transparent box with an opening on the left. All the babies succeed, some more quickly, others less so, in finding the opening and pulling out the coveted toy amid cheering by mother and tester. The next stage is the interesting one. The tester again rattles the toy and returns it to the transparent box – but this time she turns the box over, so the opening appears on the right side. The results are indisputable: Babies who are being raised in a bilingual home have twice as much success in getting the toy out of the box in the second part of the experiment as babies exposed to only one language at home.
“That doesn’t mean that bilingual babies are smarter or have a higher IQ,” Kuhl is quick to explain. “But they do have a special feature, called cognitive flexibility. It’s part of the executive functions, the control of attention and inhibitory control. It’s like they know there are two ways of saying something, there are two ways of doing something, because of cultural differences. And they get better at doing this.”
The experiments Kuhl has been describing make it sound as though everything is social and there’s no place for heredity. Where does the genetic element come in? Genetics, she says, plays a part in an infant’s inclinations, but environment exercises an enormous influence. Genes can reduce or increase our reactions to environmental stimulation, but only by a little.
To prove her point, she refers to a series of experiments conducted in a language she calls “Motherese,” referring to the intuitive way in which adults address babies. Kuhl found that this form of intuition differs from that which adults use in addressing one other in terms of three criteria: pace (speech addressed to infants is slower), tone (the sound is higher) and vocabulary (simpler words). She also discovered that this form of speech characterizes adults all over the world, irrespective of the language they speak. In her talk, she shows a video of an American mother who speaks English to her 4-month-old baby daughter, and afterward addresses a woman of her age in English. She then shows an identical video, with one difference: The woman in it is Japanese. An analysis of the sound waves of the forms of speech used by the two mothers in addressing the babies, as compared with their mode of addressing the adults, reveals clearly the same differences of tone, pace and vocabulary.
The objects of Motherese – the infants – respond to the language joyously. Experiments have shown, Kuhl says, that they turn their head, kick their feet, smile and listen attentively. Hearing Motherese appeals not only to an infant’s cognition, but also to the social brain. It’s like receiving a signal that the person opposite is willing to make an effort to communicate, is drawing close in order to have a conversation, that the infant is important to that person. Another experiment conducted in Kuhl’s lab found that infants whose parents addressed them in Motherese possessed a larger vocabulary.
Kuhl discovered that parents can be taught to speak to their children in Motherese. She held instructional sessions for parents in which she showed the statistical correlation between the use of Motherese and the child’s vocabulary, and explained how to achieve this result. At the same time, she set up a control group of parents who hadn’t undergone the training. Unsurprisingly, infants whose parents underwent instruction had a larger vocabulary. Kuhl notes that she and her staff were greatly encouraged by the fact that instructions to parents in this regard could generate major change by simple means.
Kuhl is most thrilled by the potential of “brain based interventions”: the application of educational programs and the training of educators on the basis of research and scientific knowledge. Kuhl feels a powerful motivation to change the world, she says, adding that today enough is known to accomplish that goal. With shining eyes she describes the programs grounded in her research which she has been able to implement to date. One of them was carried out in Spain.
“We went to middle- and lower-class neighborhoods and did an intervention – one hour per day of social play with language, with English, for 18 weeks – and they’re hearing Spanish in their homes and normal classrooms. The data were amazing.” At all ages, in elementary school, the children knew basic English. When you play in a new language, you learn that language, Kuhl says, and she and her staff have proved that wherever the program has been implemented. In Spain, where few people speak a second language, the program was considered a dazzling success. The Madrid municipality plans to apply it in 13 schools next year.
As for the future, the brain is endlessly fascinating, Kuhl says, “and we have only begun to scratch the surface.” The human brain is capable of accomplishing wonders in such areas as music, language, poetry, philosophy and the system of laws, but also of giving rise to unspeakable horrors. It’s riveting to try to understand what happens in the brain in either direction – how it can create both beauty and ugliness, Kuhl observes. The future of the field lies in understanding how that is possible.