Arnold Kling  

Heckman on Inequality

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James Heckman writes,


Family environments of young children are major predictors of cognitive and socioemotional abilities, as well as a variety of outcomes such as crime and health.

...Family environments in the U.S. and many other countries around the world have deteriorated over the past 40 years.

...interventions early in the life cycle of disadvantaged children have much higher economic returns than later interventions such as reduced pupil-teacher ratios, public job training, convict rehabilitation programs, adult literacy programs, tuition subsidies or expenditure on police.

...The longer society waits to intervene in the life cycle of a disadvantaged child, the more costly it is to remediate disadvantage.

Read the whole paper. In my opinion, Heckman is one of the most careful researchers on the topic, and this paper is an outstanding summary of his findings.

A key point that the year 2000 Nobel Laureate makes is that more young people in America are being born and reared in disadvantaged family environments than was the case 50 years ago.

An important inference to draw from the paper is that trying to reduce economic inequality by, say, subsidizing more young people to go to college, is likely to be very ineffective. Even interventions at the primary school level are mostly too late.


Most of the gaps at age 18 that help to explain gaps in adult outcomes are present at age five. Schooling plays a minor role in creating or perpetuating gaps.

...While more educated women are working more, their families are more
stable and the mothers in these families are also devoting more time to child development activities than less educated women. Children in affluent homes are bathed in financial and cognitive resources. Those in less advantaged circumstances are much less likely to receive cognitive and socioemotional stimulation and other family resources. The family environments of single parent homes compared to intact families are much less favorable for investment in children.

One of Heckman's themes is that while IQ is difficult to change with intervention, it is possible to affect what he calls socioemotional skills, and those in turn will affect performance on test scores and overall achievement.

Programs that target the early years seem to have the greatest
promise...Programs with home visits affect the lives of the parents and create a permanent change in the home environment that supports the child after center-based interventions end. Programs that build character and motivation that do not focus exclusively on cognition appear to be the most effective.

In the conclusion to his paper, Heckman stresses making sure that these early interventions "respect the sanctity of early family life and...cultural diversity." It is not clear that the basis for this concern is practical, or whether it is because Heckman is experiencing queasiness over promoting state intervention into family life. I can appreciate a libertarian concern with having the state take a large role in child-rearing. I am less persuaded if the concern is one of political correctness, where you want the state to intervene but then fret about the self-esteem of the families or groups where the intervention is undertaken.


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The author at 曼昆/Greg Mankiw's Blog in a related article titled Heckman on Ability Gaps writes:
    This fascinating survey by Nobelist Jim Heckman (via Arnold Kling) make the following case: Cognitiv... [Tracked on June 22, 2008 12:46 AM]
COMMENTS (7 to date)
BC writes:

Since both IQ and major personality variables are substantially inherited (IQ about 50-80 percent heritability, and personality about 50 percent) this leaves relatively little unexplained variance left over for everything else to influence. (BTW it is likely that these numbers are under-estimates due to mis-classification errors).

And some of this left-over variance (probably more than we thought) is due to 'somatic gene mutations' accumulated after conception. Some other stuff is random accidents.

What's left of the transmission between generations is divided up among a multitude of systemically varying 'environmental' factors. But this is very poorly-understood; and there is currenttly - I think - no *robust* knowledge of how to affect outcomes by manipulating these variables.

And, against these uncertainties piled upon uncertainties, we have demographic change due to factors such as the changing composition of the population due to migration and the differential reproduction of the population due to big differences in fertility rates according to IQ and personality - these changes _must_ be having big effects.

Surely demographic change is the most scientifically-plausible cause of the changes Heckman describes?

But even discussing demographic change is taboo, so I think there is a near-zero chance of socio-political interventions to change demographic trends.

Which leaves genetic engineering as the only potentially effective intervention. I am beginning to think of genetic engineering as an imperative, rather than a optional enhancement.

Mark Seecof writes:

A fascinating paper. This paper does not use the term "executive function," but Heckman has previously used that term and I think we can fairly assume that the "noncognitive abilities" he discusses in this new paper include chiefly executive function. A new paper, of which Heckman could not have been aware while writing his paper, will apparently suggest that executive function is strongly heritable, and may be largely genetic. Now, Heckman's paper goes to some trouble to show that environmental factors bear strongly on development, even to the extent of modulating the expression or effect of genetic differences. Heckman suggests that changing the infant environment may improve the development even of infants with less impressive genetic endowments. The core of his argument is undoubtedly correct, but the conclusions he draws may be somewhat overstated. Basically, Heckman builds up his thesis that massive intervention into how people raise their infants could greatly improve social outcomes by taking the most favorable interpretation of the evidence for each link in his chain of reasoning. For example, he cites works like the long-ago Perry Preschool project but does not dwell on the relative mediocrity of long term results from them, preferring to cherry-pick the good news. Also, Heckman nods toward the importance of cognitive factors in human achievement, but then chases off after non-cognitive values because he thinks they are more malleable. Even if they were perfectly malleable, such factors are more of a complement to than a substitute for cognitive ability. Favorable non-cognitive abilities predict better social integration and behaviour than otherwise, and would be worth developing for that reason alone, but must be complemented with cognitive abilities to predict high intellectual achievement. Heckman fails to address the essential paradox (which Murray and Herrnstein did not ignore) that the more you equalize environmental factors (and I will add, non-cognitive abilities), the more non-environmental (genetic) factors will predict the dispersion of outcomes in the long run. Over time we may learn that while we can promote a happier society by improving infant environments, that may not do away with the big bell curve.

dearieme writes:

I try to think of large-scale experiments on intervention in child-rearing, and what is now said about them. For instance, the Australian attempt, now routinely excoriated by reference to The Stolen Generation.

KDeRosa writes:

I'd also point out that Heckman's reliance on the Perry Preschool Project is misplaced.

The PPP was a very small (N about 50) study whose effcets have never been replicated. The research was collecetd by the same people who ran the PPP intervention. And, there were some methodically inconsistencies. Moreover, when these same researchers developed a similar program for K-3 that was independently researched on a much larger scale, the program failed miserably. See Project Follow Through, Cognitive Curriculum (High Scope) intervention which performed worse than the control group.

Steve Sailer writes:

In effect, it appears, Heckman is largely giving up on his angry 1995 review of The Bell Curve in "Reason" and is now adopting what has been Charles Murray's position all along -- that non-IQ factors (i.e., character) offer us more hope for improvement.

Floccina writes:

I have become convinced that attempting to teach children more or make them more intelligent (without the use of drugs or bioengineering) will yield very, very, very little perhaps even negative results (see above post about The Stolen Generation) and so we should focus on what we teach rather than how early we start or how well we teach. IMO there is a lot to gain by making schooling deliver more practical information (and BTW more interesting information).

Ted Craig writes:

The 50-year figure seems like cherry-picking. Why not 75 years? The variation between 1933 and 2008 would be far smaller, I'm guessing. What was the difference? In theory, with the easy availability of abortion today, fewer children should be born into disadvantaged circumstances.

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