From the NYT:
By WILLIAM YARDLEY
Published: October 25, 2012
Betty Hart, whose research documenting how poor, working-class and professional parents speak to their young children helped establish the critical role that communicating with babies and toddlers has in their later development, died on Sept. 28 in hospice care in Tucson. She was 85 ....
Dr. Hart was a graduate student at the University of Kansas in the 1960s when she began trying to help poor preschool children overcome speech and vocabulary deficits. But she and her colleagues later concluded that they had started too late in the children’s lives — that the ones they were trying to help could not simply “catch up” with extra intervention.
At the time, a prevalent view was that poor children were essentially beyond help, victims of circumstances and genetics. But Dr. Hart and some of her colleagues suspected otherwise and revisited the issue in the early 1980s, beginning research that would continue for a decade.
“Rather than concede to the unmalleable forces of heredity, we decided that we would undertake research that would allow us to understand the disparate developmental trajectories we saw,” she and her former graduate supervisor, Todd R. Risley, wrote in 1995 in “Meaningful Differences in the Everyday Experience of Young American Children,” a book about their findings, which were reported in 1992. “We realized that if we were to understand how and when differences in developmental trajectories began, we needed to see what was happening to children at home at the very beginning of their vocabulary growth.”
They began a two-and-a-half-year study of 42 families of various socioeconomic levels who had very young children. Starting when the children were between 7 and 9 months old, they recorded every word and utterance spoken to them and by them, as well as every parent-child interaction, over the course of one hour every month.
It took many more years to transcribe and analyze the data, and the researchers were astonished by what they eventually found.
“Simply in words heard, the average child on welfare was having half as much experience per hour (616 words per hour) as the average working-class child (1,251 words per hour) and less than one-third that of the average child in a professional family (2,153 words per hour),” Drs. Hart and Risley wrote.
“By age 4, the average child in a welfare family might have 13 million fewer words of cumulative experience than the average child in a working-class family,” they added.
Isn't there a giant assumption in this famous calculation: that the one hour per month of child-parent interactions that Hart & Risley recorded are representative of the entire month? Don't some of these non-welfare parents have jobs, during which periods they can't be talking to their children?
Let's try the math. Say the average 0 to 4 year old is awake 10 hours per day, or 3,600 hours per year, or 14,400 hours in those four years. If the working class family talks at the child 635 more words per hour than those famously laconic welfare families, then that comes out to a differential of 9,144,000 words, not 13,000,000 words. So the working class family must be talking at their children not just ten hours per day, but more like 14 hours per day, leaving only 10 hours per day for the poor child to sleep (or to talk himself or to watch TV or to play with his blocks or to watch the cat or to daydream).
Shouldn't somebody call Child Protective Services and report all the non-welfare families in the country for child abuse due to incessant chatter?
They also found disparities in tone, in positive and negative feedback, and in other areas — and that the disparities in speech and vocabulary acquisition persisted into school years and affected overall educational development.
So, parents with big vocabularies tended to have children with big vocabularies. (Also, I would imagine, parental skin tone, height, and hair color tended to correlate with their children's skin tone, height, and hair color.)
“People kept thinking, ‘Oh, we can catch kids up later,’ and her big message was to start young and make sure the environment for young children is really rich in language,” said Dr. Walker, an associate research professor at Kansas who worked with Dr. Hart and followed many of the children into their school years.
I recommend taking your preschoolers to Tom Stoppard plays. Start with The Real Thing no later than 30 months and work up to Arcadia by at least the fourth birthday. Also, read to them every night from Nabokov. Pnin is an easy start, but they should be finished with Ada by the time they enter kindergarten.
The work has become a touchstone in debates over education policy, including what kind of investments governments should make in early intervention programs. One nonprofit program whose goals are rooted in the findings is Reach Out and Read, which uses pediatric exam rooms to promote literacy for lower-income children beginning at 6 months old.
Prompted by the success of Reach Out and Read, Dr. Alan L. Mendelsohn, a developmental-behavioral pediatrician at Bellevue Hospital and New York University Langone Medical Center, pushed intervention even further. He created a program through Bellevue in which lower-income parents visiting doctors are filmed interacting and reading with their children and then given suggestions on how they can expand their speaking and interactions.
“Hart and Risley’s work really informed for me and many others the idea that maybe you could bridge the gap,” Dr. Mendelsohn said, “or in jargon terms — address the disparities.” ...
I don't see any mention here of experimental research, just tracking of existing differences that are compatible with most combinations of nature and nurture theories.
“Today, much of her research is being applied in many different ways,” said Dr. Andrew Garner, the chairman of a work group on early brain and child development for the American Academy of Pediatrics. “I think you could also argue that the current interest in brain development and epigenetics reinforces at almost a molecular level what she had identified 20 years ago.”
One obvious but little mentioned implication of this popular line of thought is: White professional mothers who hire semi-literate nannies who have smaller vocabularies in English than in Spanish and smaller vocabularies in Spanish than in Mayan to raise their children for them while they put in the hours to make partner or get tenure are dooming their offspring to only getting into State U. You see, by not personally speaking to their small children for much of the day using their high level vocabularies, Hart & Risley's logic says their kids are in big, big trouble.
And, indeed, many white mothers behave exactly as if this were true.
For example, one of my early bosses in the marketing research business was Kathie, a hard-charging, funny, foul-mouthed MBA who let nothing stand in the way of our team making the numbers. Then I heard a rumor that she and her boyfriend, an MBA at a big corporation, were going to take a little time off from each other. Then she started going to the gym at lunchtime, lost ten pounds, and then showed up one Monday morning wearing an engagement ring and a big smile: her ex-boyfriend was now going to be her husband. Marriage and a baby ensued, but she was right back on the job a month after giving birth. Then she got pregnant again, and came back to the job a couple of months after giving birth. But within a week of her return, she announced she was permanently retiring to be a housewife. Management tried hard to talk her into part-time work or taking just a couple of years off or whatever she wanted, but she was adamant that she was done with working: she was a full-time mom from now on.
Of course, Kathie's trajectory was feasible because her husband was making good money. But, her emotions are common.
Of course, this pro stay-at-home-mom implication of the Hart & Risley conventional wisdom is not played up in the press, which is largely run by women who are not stay-at-home-moms and who frequently feel guilty about it if they do have children or resent those women who are mothers, and thus try to put them down by emphasizing how glamorous and politically important it is to be a working woman.
What does the research say on stay-at-home mothers vs working mothers in terms of children's cognitive development? I haven't looked in a long time, but my recollection was that it's inherently uncertain because nobody can run a controlled experiment. Mothers are constantly adapting to what they think is best for their children (e.g., Kathie), trying to optimize a variety of factors that differs for each family and, indeed, for each child.
That moms refuse to follow experimental methodologies when it comes to their own kids is bad for science, but good for children.