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.