Subject 046M, two years old, was seated nervously across from me at the table, his hands clasped tightly together in his lap. He appeared to have caught an incurable case of the squirms. I resisted the urge to laugh and leaned forward, whispering conspiratorially. “Today we're going to play a game with Mr. Moo.” I produced an inviting plush cow from behind my back. “Can you say hi to Mr. Moo?”

That spring I was a newly minted researcher in the laboratory of cognitive scientist Michael Ramscar, who was then at Stanford University. Ramscar was studying how children go about what is arguably the most vital project in their schooling—learning language. We were particularly taken with the question of how kids learn a small but telling piece of that vast complex: color words. We wanted to know how much kids know, when they know it and whether we can help them get there faster.

046M (“M” for male) was off to a good start. I arranged three color swatches in front of him. “Can you show me the red one?” He paused, then pointed to the middle rectangle. “Very good!” I said, beaming. “Now, what about the one that's blue?”

The test was not designed to trip kids up. Far from it—we tested only basic color words, and we never made them pick between confusable shades, such as red and pink. To an adult, the test would be laughably easy. Yet after several months of testing two-year-olds, I could count my high scorers on one hand. Most would fail the test outright. 046M, despite his promising start, proved no exception.

There is a surprising disconnect between what children seem to know about colors and numbers and what they actually demonstrate when tested. Nailing down just what “red” or “three” means is a difficult hurdle in mastering language, and even older children sometimes slip up and reveal a less than expert grasp of these concepts. We discovered in our lab that the way we use color and number words in everyday English actually impedes kids' learning.

Parents see their children's color and number knowledge as developmental milestones for good reason—these concepts lay the foundations for key aspects of perceptual and numerical reasoning. Our research revealed that if we understand how the developing brain makes sense of speech, we can help children reach these milestones more painlessly. By phrasing things slightly differently, adults can help youngsters to grasp colors and numbers—and therefore advance to a higher understanding of language—much earlier in life.

Red Apples, Blue Skies

Before each experimental session began, a research assistant would explain to the child's parents that we would be testing color words. Responses were typically enthusiastic. “Oh, that's great! Margie's got her colors down pat.” At that point we leveled with them: if they wanted to be present during the study, they would have to be blindfolded. Such measures may seem extreme—but then again, so were the reactions we got from parents during the pilot study, as they watched their little ones fail to pick out the correct hue, over and over again. The reactions ran the short line from shocked to terrified and back again. Some parents were so dismayed they started impatiently correcting their children midtest. One mother, in particular, could not seem to stop herself and took to nervously grabbing her little boy's hand whenever it started to veer away from the correct choice.

Then, inevitably, came the post-test breakdown: “Is my child color-blind?”

The baffled response is not new. Charles Darwin was startled by his own children's failings when it came to color, writing in 1877: “They could not name the colors, although I tried repeatedly to teach them.” About a century later developmental psychologists began to systematically determine what it was that made learning color words so hard for kids. The obvious hypotheses were soon ruled out. First, children are not color-blind. They can perceptually distinguish colors within a few months of birth. Nor do kids lack experience with color words, which are common in speech and some of the first words in their vocabularies.

A typical toddler, for example, can use colors appropriately in common phrases, such as “yellow banana,” “blue sky” and “red fire truck,” and can even correctly answer familiar questions such as “What color is a tomato?” This apparent mastery is why parents are so often convinced their kids are color experts. But they might be far less confident if they realized that blind children are capable of much the same feat. It turns out that kids can learn to use color words in context simply by paying attention to how things usually get talked about—for instance, the word “red” tends to come up a lot with “fire trucks” but not so much with “ice cream.”

Take away that crucial context, and most two- and three-year-old kids are stumped—they cannot correctly identify colors in a lineup or accurately use color words in novel scenarios. What is more, psychologists have found that even after hours and hours of repeated training on color words, performance typically fails to improve noticeably, and children who are as old as six continue to make major errors naming colors. This last fact is seriously bizarre when you consider all the other things that children at that age can do: ride a bike, tie their shoes, read the comics and—mistake a blue cupcake for an orange one? Really?

Really. And that is where 046M and his color-naming compatriots came in. Armed with the tools of cognitive psychology, we decided it was high time to figure out why it takes so long for children to learn colors, of all things, and whether we could shortcut the process.

The Grass Is Green

Psychologists before us have pointed out that part of what complicates color learning is that we are constantly surrounded by a vast array of hues. This overwhelming ubiquity is not a feature of other common words, such as nouns. Imagine, for example, that a child is trying to learn to distinguish “dog” from “bear.” The learning problem is not so difficult in this case: unless you are watching Old Yeller, dogs will tend to be seen and talked about in contexts in which bears are not present, and vice versa.

Contrast this with the problem of learning color words. In most situations when a three-year-old hears “red” there will be a kaleidoscope of other colors present. Sorting out which hues are “red” and which are “orange” is much harder than figuring out which furry beasts are “bears” and which are “dogs.” This may explain why children, across every language studied, invariably learn their nouns before their colors.

As it happens, English color words may be especially difficult to learn because English speakers throw in a curveball by using color words “prenominally,” meaning before nouns. For instance, we will often say things like “the red balloon,” instead of using the postnominal construction, “the balloon is red.” Our study set out to determine if our choice of word placement could actually influence kids' ability to learn colors.

Sentence construction matters, in theory, because of how attention works. In conversation, people have to track what is being talked about, and they often do this visually. If I were to start referring to “the old fnord in the corner,” you would probably begin quickly glancing around for the mystery person or object.

Kids do the same thing, only more avidly, because they have much, much more to learn about. That means that when you stick the noun before the color word, you can successfully narrow their focus to whatever it is you are talking about before you hit them with the color. If you say “the balloon is red,” for example, you will have helped narrow “red” to being an attribute of the balloon and not some general property of the world at large.

From what we can decipher, children also figure out that the “red” in “the red balloon” has to do with the balloon, but they interpret it differently. When we say “the balloon is red,” they learn that “red” is the name of a property, such as “wet” or “sharp,” whereas when we say “the red balloon,” they learn that “red” is more like a proper name, such as “Tom” or “Heather.” Knowing someone's name does not usually reveal as much as knowing that someone is cruel or kind. Whether kids learn “red” as something like a name or something like a property depends entirely on how their attention is directed when they hear it.

Helping Kids Learn Hues

Our hypothesis was simple: using color words after nouns should make colors far easier to learn and kids far faster at learning them. To test this idea, we took a group of two-year-olds and gave them some quick training on color words. Either we trained them with prenominal sentences (the standard variety in English) or postnominal sentences (helpful, we hoped). In both cases, we would simply show them familiar objects and say encouraging things such as “this is a blue crayon” or “this crayon is yellow.”

As we reported in August 2010 in Cognitive Science, the kids who got the postnominal training improved significantly over their baseline test scores, whereas the ones who got the prenominal training still looked just as confused as ever. Given that previous studies had not found much improvement after hundreds of explicit training trials, it was hard to believe that such a simple manipulation could make such a clear difference. And yet it did.

Next up, we ran a similar experiment using numbers instead of colors. To assess how well our young subjects understood numbers, we first asked them, “Look, hearts; can you show me four?” and “Can you show me four hearts?” We then trained the kids on number words, one group prenominally and one postnominally. Here again the sentence construction made all the difference. After only 15 minutes of training, youngsters who learned postnominally (“Flowers! There are six”) dramatically improved their test scores, averaging 30 percent better in both reliability and accuracy. Those who we trained prenominally (“There are six flowers”) showed no improvement.

Considering that early number comprehension is a good indicator of how well children will do in math later in life, helping kids learn numbers at a younger age could very well have a long-lasting influence. Which brings me to the key, take-home point: if you want your two-year-old to match colors with aplomb and count with ease, watch your tongue. It might seem faster to ask Johnny not to pop “the red balloon,” but it may be better for him if you rephrase: “I mean, the balloon that is red.”

Pass the Blue

In English, we tend to position adjectives before nouns (“the green grass”), an ordering preference that can make it harder for kids to learn their colors and numbers than if we were to reverse the sequence ("the grass is green”). Many other languages naturally use the latter construction, placing adjectives after the nouns they describe. Does that mean a child growing up in a French- or Spanish-speaking household will grasp the concept of colors more easily?

The short answer is we do not know. Elise Percy and her colleagues have found that word order biases can influence how speakers of different languages organize information in memory. But studies have not yet been done comparing color learning between prenominally biased languages and postnominally biased ones. The outcome of such a study might not be so predictable, because many of those languages come with curveballs of their own. In Spanish, for instance, speakers often omit nouns in casual conversation. Whereas English speakers will ask for the “blue bowl,” Spanish speakers can just as gracefully demand “the blue.” —M.D.