Early childhood, when brain plasticity and neurogenesis are very high, is a key period for the development of skills (both cognitive ans psychosocial). Differences in this early investment might be the seeds of inequalities observed later in life across countries and within countries. More than 200 million children under the age of 5 are at risk of not reaching their full potential, the majority of them living in extreme poverty. Starting from a disadvantaged point, Figure 1 shows that remediation later is less effective and more expensive than early interventions.
Figure 1: Returns to investment by age.
Source: Heckman (Economic Inquiry, 2008)
An experimental study in Jamaica, recently published in Science, has provided more rigorous evidence on the benefits of early childhood investment. Growth-stunted children - reliable indication of severe economic disadvantage in developing countries - between the ages of 9 and 24 months participated in a 2-year randomized controlled trial. Usually we cannot compare the benefits of parents who themselves decide to promote their children's situation because of selection issues. For example, parents who invest in education are probably different in many characteristics from those who do not (maybe more motivated or caring for example). Hence, we would be comparing both the increased investment as well as parents "quality." To avoid this issue, the Jamaican study randomly assigned children to one of four groups: 1) psychosocial stimulation (explained below); 2) nutritional supplementation (1 kg milk-based formula per week); 3) both psychosocial stimulation and nutritional supplementation; and 4) a control group that did not receive treatment. Another group of non-stunted children was surveyed to provide a external comparison group, so that the question "Were these children able to catch-up?" were possible to answer.
Groups 1 and 3 participated in a program that consisted of two years of weekly one-hour sessions at home focused on improving parent and children interaction, with innovative activities to develop child cognitive, language and psychosocial skills. They were also encouraged to practice the activities and games learned during the visit beyond the home visitation time. The particularly interesting element of this project was the length of time for which children were studied. Participants were interviewed 20 years later and evaluated on a number of economic indicators. While stunted growth is largely due to a lack of nutrition, the nutrition intervention alone didn't affect later adult economic outcomes. The nutrition-only group showed no long-term effect on any measured outcome, but this may be due to the sharing of the nutritional supplementation within the family. On the other hand, psychosocial stimulation seems to have brought substantial long-term benefits.
In addition to improving direct parent-child interaction during the 2 years of the program, it seems that it also promoted greater parental investments later in life with an improved home environment, which probably improved later outcomes. Years of education increased by an average of 0.6 years by age 22, while college attendance increased three-fold. Even though they were also more likely to be in school (and hence working below their potential), their income was between 40 and 60% higher among those who received early psychosocial stimulation. Early intervention also reduced involvement in violent crimes.
Finally, could they catch up to remediate their initial disadvantages? Yes. The differences in income between children who were disadvantaged but received early stimulation and those who were not disadvantaged was zero (or not significantly different from zero). Early improvements probably encouraged the families to seek greater education and employment opportunities. 22% of the families in the treatment group emigrated to countries with great opportunities for upward mobility, compared with only 12% of the control group families.
These results are remarkable. Returns to early intervention are close to 10%, much higher and more persistent than other alternatives later on in life. So why are policies concerned with inequality so focused on re-distribution later on in life? Maybe instead we should try to pre-distribution during the earliest stages of life.
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