This article is part of Promoting Social Mobility, a forum on using early intervention to reduce inequality.
James J. Heckman
I thank the respondents for their comments. Their interesting points deserve more than the abbreviated response I can give here.
My analysis is cast in a life cycle perspective. It considers the origin of the multiple skills that produce success or failure in many aspects of life. It analyzes the consequences of life cycle dynamics through which family investments and social environments produce cumulative advantages and disadvantages. Skills beget skills. The early years are crucial in creating the abilities, motivation, and other personality traits that produce success downstream: in school, in the workforce, and in other aspects of life. Environments and investments matter for producing skills over the entire life cycle but are particularly effective when children are very young—from birth to age five.
Cognitive skills solidify by age eleven or so. For them, early development is important. Personality is malleable until the mid-twenties. This is a consequence of the slowly developing prefrontal cortex that regulates judgment and decision-making. These fundamental biological and psychological facts explain why successful remediation strategies for adolescents focus on improving personality skills. I cite evidence from effective early intervention programs with 30 or more years of follow-up. They have been rigorously evaluated and show benefit-cost ratios and rates of return that compete with those of stock market investments in normal years.
All of the respondents agree that the early years are important and that families play important roles in shaping the child. Lelac Almagor and Carol Dweck note that it would be helpful to parse out which features of the successful interventions lead to success—to “go into the black box” of program treatment effects. I agree. My colleagues and I have done so by establishing that the substantial effects of the Perry program are due to improvements in the personality traits of the participants. The next generation of intervention studies needs to move beyond reporting treatment effects in order to understand the precise interventions that produce the measured effects and the mechanisms through which they operate.
Charles Murray mischaracterizes the quality of the evidence on the effectiveness of early childhood programs. In doing so he suggests that my evidence is highly selective. The effects reported for the programs I discuss survive batteries of rigorous testing procedures. They are conducted by independent analysts who did not perform or design the original experiments. The fact that samples are small works against finding any effects for the programs, much less the statistically significant and substantial effects that have been found.
Murray questions whether any early childhood interventions can be effective because while some have worked, others have failed. His methodological stance is peculiar. In evaluating drugs to control blood pressure, we do not dwell on the failures except to learn from them. We should implement the successes. That is common sense and sound science. Perry and Abecedarian are rigorously evaluated, subjected to long-term follow-up scrutiny, and have shown high economic rates of return. Neal McCluskey’s claim that Perry is costly and has few benefits does not hold up. Perry’s high rate of return takes account of the program’s costs.
Murray misrepresents the evidence from the Infant Health and Development Program (IHDP) in an attempt to bolster his argument. IHDP was not a replication of Abecedarian, but rather an application of the Abecedarian model to a low–birth weight population—not the target population of Abecedarian. The designers of IHDP recognized in advance of collecting the data that severely low-weight children had medical needs not likely to be addressed by the Abecedarian curriculum. IHDP had substantial benefits for high–birth weight babies at ages of eight and eighteen. It was particularly effective for children from low-income families, and it promoted maternal employment.
The right interventions empower people to be what they want to be without forcing them to adopt one way of life over another.
In addition, the evaluations of IHDP (discussed by Murray) and Head Start (discussed by Almagor and McCluskey), do not account for David Deming’s point that many members of the control groups of those (and other) studies were enrolled in other early childhood programs, biasing downward simple treatment-control comparisons. (This is called “substitution bias” in the literature.) For these and other programs, there is the additional problem that treatment intensity varies among subjects. Adjusting for these biases boosts estimated program treatment effects. Also, Head Start is a very heterogeneous program and has not had any long-term follow-up, so evaluations of it are not comparable to those of Abecedarian and Perry.
Robin West correctly notes that one benefit of early childhood programs is the provision of childcare. It frees the mother to work and advance her education and career. However, quality childcare is essential. Warehousing a child in substandard daycare can cause harm.
As West, Geoffrey Canada, and Harry Brighouse and Adam Swift suggest, interventions with parents promote their employment and skills. They also create lasting improvements in the quality of parenting through direct instruction and by increasing family resources.
Adolescent interventions that target personality skills also appear to have benefits. I agree with Mike Rose that workplace-based education can foster these skills. Few of these programs have been rigorously evaluated with long term follow-ups, though. The available evidence, such as it is, suggests returns substantially lower than those found for early childhood interventions.
The GED program is an exception to the rule that few adolescent programs have been evaluated with long-term follow-ups. These evaluations reveal that GED recipients from almost all demographic groups perform poorly because the GED program does not remediate their deficient personality skills.
I hope that Dweck is correct that there are effective adolescent interventions that compete with the benefits of Perry. The jury is out. There are no long-term, rigorous evaluations of her programs or any benefit-cost or rate-of-return calculations associated with them. Due to the synergisms I discuss, the returns to adolescent interventions will be greater among the more skilled participants in her programs. Thus, I agree with Canada that adolescent interventions and early childhood interventions are complementary, not rivalrous, activities.
Brighouse and Swift and Annette Lareau flirt with cultural relativism and talk about differences in cultural values across groups. They implicitly suggest that I seek to impose a common template on all children. Their discussions miss the point. A core set of cognitive and personality traits are universally valued across cultures. Those traits promote autonomy, dignity, and human flourishing. They empower people to be what they want to be and do not force them to make particular choices or adopt one way of life over another. The rigorously evaluated programs that I discuss (including the Nurse-Family Partnership) are voluntary and non-stigmatizing, and they offer choices, information, and supplementary assistance to parents and children. These programs respect the dignity of the family but also respect the challenges that many families face.
To comment on this forum, click here to return to the lead article by James J. Heckman.
James J. Heckman is a Nobel laureate and the Henry Schultz Distinguished Service Professor of Economics at the University of Chicago. His article is based in part on his paper Schools, Skills, and Synapses.
Promoting Social Mobility, a forum with James J. Heckman, Mike Rose, Robin West, Charles Murray, Carol S. Dweck, and others.