Just to be clear, we'll be talking here about class, folk psychology, and my high school math teacher. But as ever, I've buried the lead. Now for some recap, before we get on to the good stuff --
In the last post, we found that the behavior exhibited in the classic cookie task is more strongly linked to vocabulary development than it is to cognitive control. This suggests that what's dictating behavior in the task can't simply be explained by appeal to the child's particular cognitive architecture. Rather, how long children hold out appears to be largely a function of their verbal skills. One conclusion we might draw from this is that how children perform in the task is related to their ability to verbally strategize.
As Mischel et al. write:
Many [of the most successful] children generated their own diversions: they talked quietly to themselves, sang, created games with their hands and feet... Their attempts to delay gratification seemed to be facilitated... by self-directed efforts to reduce their frustration during the delay period by selectively directing their attention and thoughts away from the rewards. (Mischel, Shoda & Rodriguez, 1989, p. 935)
While not all of these diversions are "verbal" in nature, it is easy to imagine how conceptualizing and implementing these types of strategies could be plausibly linked to verbal ability. Indeed, it seems reasonable to assume that greater verbal prowess would facilitate more sophisticated (and more effective) distraction strategies, which would then result in greater delay times.
Of course, as my high school statistics teacher, Mrs. Grande, would be quick to point out – correlation does not imply causation. Simply because vocabulary and delay are highly correlated doesn't mean that verbal ability is necessarily what's driving delay in the task (though that is certainly a very plausible explanation, and one I would hedge my bets on).
For the moment, however, let's entertain a subtly different possibility : that vocabulary is a kind of cultural index, which is a measure of a child's environment. The possibility then, is that it is the particulars of that environment that is driving both the vocabulary scores and the delay times, in tandem.
"At the opposite extreme is the person who predominantly prefers immediate gratification and declines the alternative of waiting or working for larger, delayed goals. Correlated with this is a greater concern with the immediate present than with the future, and greater impulsivity. Socioculturally, this pattern is correlated with membership in the lower socioeconomic classes, with membership in cultures in which achievement orientation is low, and with indices of lesser social and cognitive competence." (Mischel, 1974)
In previous research, Mischel has found that children from lower socioeconomic backgrounds tend to perform worse than upperclass children on tests of delay of gratification. Given that he's also found that the time children spend delaying in the cookie task is predictive of a suite of life outcomes – including everything from their later social well-being to their academic achievement and professional advancement – he makes a logical leap: Might social classes diverge, he asks, based on our ability to exercise self-control?
It's critical that I note that Mischel is not a biological determinist on this . He is not suggesting that people who live in poverty are all simply indolent and stupid, or that they are somehow morally suspect. To the contrary, Mischel tends to remove all moral weight or judgment from his discussions of self control, and in much of his work, characterizes control as a largely learned behavior. If he makes generalizations on the basis of class (which he does), I believe this derives more from his training as a scientist, and less from any particular political attitudes or leanings. He is simply looking to make sense of trends in human behaviors, and uses "delay of gratification" as a prism through which to understand them.
In any case, the question Mischel poses become doubly interesting in light of Ramscar and Tran's findings. As detailed above, and in earlier posts, their results indicate that “self control” behavior in the cookie task is strongly tied up with verbal ability. Indeed, they found that vocabulary is a better predictor of delay times than age or cognitive control.
What I haven't mentioned yet – and what may surprise you – is what predicts vocabulary.
As it turns out, one of the best predictors of how many words a toddler knows is socioeconomic status.
Why? The problem arises from a major learning gap: on the whole, children from lower socioeconomic backgrounds tend to be exposed to far less language than their wealthier counterparts. A classic longitudinal study by Betty Hart and Todd Risley (1995) found that disadvantaged children hear far fewer word-types and far fewer words spoken overall, and receive less feedback and guidance in their production from their parents. To be clear: children from welfare families hear on the order of thousands fewer words per day than children from professional families, leading to what Hart and Risley term a “meaningful difference” over time. While it is difficult to quantify the impact this impoverished input has on learning, many researchers believe the effect to be massive. Just to give you an idea – by the age of three, children from professional families actually have larger recorded vocabularies than the parents of the welfare families.
Further, there is a wealth of evidence to suggest that early childhood language development influences the course of subsequent learning, and is highly predictive of later cognitive and linguistic competence. Developmental psychologists Virginia Marchman and Anne Fernald have found, for example, that a child’s aptitude for learning new words is predicated on her early exposure to language. The implication is troubling: how much a child learns early on shapes how well she’s able to learn later. This then leads to a vicious cycle: children of parents with impoverished vocabularies are at high risk of growing up to become parents of children with impoverished vocabularies.
The issue is not insignificant. How many words a child knows is not simply a rootless number, with little bearing on subsequent education and achievement. Many psychologists believe that vocabulary is a core marker of general intelligence, and performance on vocabulary inventories and indices is highly correlated with IQ scores. Taken together, these findings paint a bleak picture in which a child’s intelligence – her capacity for subsequent learning – even her ability to distract herself in the cookie task – all may be intimately bound up with her early experience with language.
It is easy to imagine why this would be so. Take a student promoted to the next grade level who has failed to master some of the foundational materials of the previous year. In all likelihood, she will simply slip further and further behind as she progresses. It is next to impossible, for instance, to try to teach a child algebra, when she lacks a firm footing in arithmetic, or to initiate a child into the workings of double-dutch, if she can’t already skip rope. If we understand that language – which is our most fundamental tool with which we grasp to the world – underpins much of our subsequent learning, then it becomes clear how devastating the effects of falling behind before preschool must be.
All of which raises a rather subversive possibility.
If you recall, I first raised the idea (hypothesis 1) that verbal ability may be driving children’s ability to effectively strategize – and thereby delay – in the cookie task. If this is the case, then it suggests that what Mischel’s experiments have been tapping into all these years, is how early language attainment charts the course of what is to come. Language is our primary mode of operating within and engaging with the world, and as such, touches everything we do and everything we understand . It may be that the cookie task, as an indirect measure of verbal ability, is telling us something about how children employ that skill to their benefit. And it may be that that ability – to effectively navigate the world through language – is what is predicting everything else.
This does not, of course, rule out the possibility that the task measures a form of “self control.” It does, however, shift the emphasis, from one of impulse control (prefrontal functioning), to one of verbal strategy and practice. And it suggests that no, classes do not diverge on the basis of some cognitive ability; rather, they diverge on the basis of language -- which is just another way of saying, they divide by social advantage .
But then, of course, there remains that pesky second possibility (hypothesis 2) : that whatever the task is measuring, is a measure of culture and environment, which is then reflected in both the vocabulary scores and the practice of “self control.” In other words, it may be that having a large vocabulary at age three tends to go hand in hand with having parents who value industriousness and temperance, who diet rigorously and exercise strenously, and who model delay of gratification at every turn, such that their children – seeing this – are both scholarly and disciplined by age three (and of course, all too cookie-avoidant).
Indeed, this may be the case, and perhaps it is tempting to characterize the socioeconomic divide in this way. But I find something suspect about supposing that the ‘toiling’ poor are somehow less able to exercise self-control than the often ‘indolent’ rich. Certainly there are the archetypes of the industrious, self-made millionaire, and the slothful welfare recipient to consider. But what of the advantages and disadvantages that fate has bestowed on our children? A child from a wealthier family will, in all likelihood, be exposed to far more language, go to far better schools, benefit from the support of tutors, never have to decide between supporting her family and continuing her schooling, and so on, and so forth. Such that, at every point in her life, she is blessed with a comparative advantage, whose benefits will simply multiply as she advances.
Is it really the case that a child who has to drop out of school to support her family is failing to exercise “self control”?
My point is: it may be true that certain cultures within American society place more value on education – for example – or the merits of “an honest day’s work.” But it's not hard to see why people from lower-income neighborhoods might be hard-pressed to value education, given the state of their local drop-out factories, or why one might be tempted to engage in below-the-board activities, when there simply is no better recourse. From this perspective, we can see that how low-SES families navigate the world may be far more indicative of the constraints the world has placed on them, than of their ability (or no) to control their own behavior .
When we then consider Ramscar & Tran's finding -- that behavior in the cookie task isn't a good mirror of good cognitive function -- it seems that the already tenuous link between class and "self control" begins to come apart at the seams.
But then again, it depends what we mean by control, doesn’t it?
Do we mean: Valuing education or quitting smoking? Waiting to get pregnant or avoiding drugs? Studying hard or running through the pain? Waiting on the cookie or holding one's tongue? We collapse all of these behaviors into one broad heading: "self control." But it's far from clear that they all take the same determinants. Whether we engage or not in these behaviors may be the product of our cultural value systems; the workings (or failings) of our neural architectures; the strategies we have learned to engage with our lives; or the idiosyncrasies of our highly particular personalities. By mixing science with self control, we've walked into a hornet's nest, a word trap, what the philosophers would call a bit of 'folk psychology.'
But now that we know -- what do we do?
The Daily Fact Check
 Let me be clear: Mischel frequently acknowledges the contribution of learning. "...an early family environment in which self-imposed delay is encouraged and modeled may nurture other types of behavior that facilitates the acquisition of social and cognitive skills, study habits, or attitudes which may be associated with obtaining higher scores...It also seems reasonable...that children will have a distinct advantage beginning early in life if they use effective self-regulatory strategies to reduce frustration in situations in which self-imposed delay is required to attain desired goals." (Mischel, Shoda & Rodriguez, 1989, p. 936)
 I want to be careful here not to set up Mischel as a straw man. Mischel is as careful a thinker as he is an experimentalist, and some of the broad strokes I've used to characterize the question he posed don't do justice to the subtleties with which he considers them. Nevertheless, I feel like this is a critical question to address, given that how we interpret and understand human behavior may shape everything from our politics to our day to day interactions with our fellow man. If you're hankering for some more on Mischel, Jonah Lehrer, darling of the science writing world and a, er, graduate of my high school, has a wonderful piece --that no doubt, you've already read-- in the New Yorker.
 For a fascinating (and provocative) application of this idea to social behavior and economics, you may be interested in Karelis' “The Persistence of Poverty: Why the Economics of the Well-Off Can't Help the Poor.” Listen to him talk shop on NPR.
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Marchman VA, & Fernald A (2008). Speed of word recognition and vocabulary knowledge in infancy predict cognitive and language outcomes in later childhood. Developmental science, 11 (3) PMID: 18466367
Hoff, E. (2003). The Specificity of Environmental Influence: Socioeconomic Status Affects Early Vocabulary Development Via Maternal Speech Child Development, 74 (5), 1368-1378 DOI: 10.1111/1467-8624.00612
Huttenlocher, J., Haight, W., Bryk, A., Seltzer, M., & et al, . (1991). Early vocabulary growth: Relation to language input and gender. Developmental Psychology, 27 (2), 236-248 DOI: 10.1037//0012-16184.108.40.206
Mischel, W., Shoda, Y., & Rodriguez, M. (1989). Delay of gratification in children Science, 244 (4907), 933-938 DOI: 10.1126/science.2658056