Word Count and Cognitive Development

Margaret Talbot has written a long and detailed article about how governments and private charities are trying to make up a gross disparity in—word count.

By that one means that some children hear more words than others. This is especially important in a child’s earliest years, even at times before he can speak himself.

The more words a child hears the better his cognitive development. Optimally, a child should hear something like 30,000,000 before age 3.

Some researchers have underscored the fact that words heard during a conversation are much more important than words that spew forth from a television set. A parent who does not talk with a child but sets the child in front of a television set is depriving him of needed verbal stimulus.

Others have added, perhaps self-evidently, that repeating the same word over and over and over again does not add to the word count. A parent’s conversation should be engaging and should include some complex thought.

So, children who hear more words through conversation tend to have a cognitive advantage over those who hear fewer. Apparently, those who hear more are more often of a higher social class. Children in a lower social class often hear fewer words.

All of these observations require qualification and clear definition. Still, it appears that word count, the number of words a child hears at a very young age matters enormously for cognitive development.

Talbot provides us with an excellent summary of the research.

In her words:

In the nineteen-eighties, two child psychologists at the University of Kansas, Betty Hart and Todd Risley, began comparing, in detail, how parents of different social classes talked with their children. Hart and Risley had both worked in preschool programs designed to boost the language skills of low-income kids, but they had been dissatisfied with the results of such efforts: the achievement gap between rich and poor had continued to widen. They decided to look beyond the classroom and examine what went on inside the home. Hart and Risley recruited forty-two families: thirteen upper, or “professional,” class, ten middle class, thirteen working class, and six on welfare. Each family had a baby who was between seven and twelve months old. During the next two and a half years, observers visited each home for an hour every month, and taped the encounters. They were like dinner guests who never said much but kept coming back.

In all, Hart and Risley reported, they analyzed “more than 1,300 hours of casual interactions between parents and their language-learning children.” The researchers noticed many similarities among the families: “They all disciplined their children and taught them good manners and how to dress and toilet themselves.” They all showed their children affection and said things like “Don’t jump on the couch” and “Use your spoon” and “Do you have to go potty?” But the researchers also found that the wealthier parents consistently talked more with their kids. Among the professional families, the average number of words that children heard in an hour was twenty-one hundred and fifty; among the working-class families, it was twelve hundred and fifty; among the welfare families, it was six hundred and twenty. Over time, these daily differences had major consequences, Hart and Risley concluded: “With few exceptions, the more parents talked to their children, the faster the children’s vocabularies were growing and the higher the children’s I.Q. test scores at age 3 and later.”

Talbot adds:

But Taveras learned that Hart, who died in 2012, and Risley, who died in 2007, had also identified important differences in kinds of talk. In the recordings of the professional families, they found a “greater richness of nouns, modifiers, and past-tense verbs,” and more conversations on subjects that children had initiated. Catherine Snow, a professor at Harvard’s Graduate School of Education, who studies children’s language development, told me that these findings made sense, since quantity was often a proxy for quality. “Families that talk a lot also talk about more different things,” Snow said. “They use more grammatical variety in their sentences and more sophisticated vocabulary, and produce more utterances in connected chains.” Such parents, she noted, “don’t just say, ‘That’s a teapot.’ They say, ‘Oh, look, a teapot! Let’s have a tea party! There’s Raggedy Ann—do you think she wants to come to our tea party? Does she like sugar in her tea?’ ” Parents who talk a lot with their young children ask them many questions, including ones to which they know the answer. (“Is that a ducky on your shirt?”) They reply to those devilish “Why?” questions toddlers love with elaborate explanations. Erika Hoff, a developmental psychologist at Florida Atlantic University, has published studies about early language development whose results are similar to those of Hart and Risley. She recalled marvelling at “the young professor mothers” at a university childcare center: “Everything was a topic of conversation. If they had to get out of the building in case of a fire, they’d be so busy discussing the pros and cons with their toddlers that I kind of wondered if they’d make it.”

We can easily understand the disparity. Parents from a higher social class are most likely to have more education. They would have read more, questioned more and had more conversations.

More educated parents had more to say to their children. Less educated parents had less to say.

Does it matter whether the parent is a mother or a father?

By my guess, it must. If women, as most people believe, talk more than men, they would be most suited to engaging in conversation with infants and toddlers. Women’s garrulousness seems to manifest an instinct toward good maternal nurturance.

If we accept that upper class women are more likely to be able to stay at home with their children, this must allow them to engage in more sustained conversation with their children. If upper class women are more likely to have household help this too must free them to speak more with their children.

Lower class women bear more of the burden of housework and are less able to take very much time off from their jobs.

It is also worth noting that day care will mostly not be able to make up for the deficit of an absent mother. If one woman is caring for a group of children in day care she will not be spending very much time in one-on-one conversation. Even quality day care cannot make up for the deficit of an absent mother.

A highly verbal nanny, on the other hand, can certainly provide as much exposure to words as would a stay-at-home mother. Again, only parents from a higher social class will have the means to hire such a nanny.