To flesh out some examples, the top fifth of the sample in terms of childhood self-control had rates of serious adult health problems at 11 per cent versus 27 per cent for the bottom fifth of the sample. The crime rates in adulthood were 13 per cent for those high in childhood self-control versus 43 per cent for those with low childhood self-control.

The relationship with adult outcomes held across the full-range of childhood self-control scores. In other words, there doesn't appear to be a level of self-control beyond which no more benefits are gleaned. Neither is there a nadir of self-control beneath which no further costs are incurred.

There was also evidence in the data for what the researchers called adolescent "snares" that trapped individuals in harmful lifestyles. For example, children with lower self-control were more likely to smoke in adolescence, to leave school with no qualifications and to become a teenage parent. In turn these teenage "snares" predicted the chances in adulthood of having poor health, financial problems or being a criminal.

Moffitt and her colleagues said their results strengthened the case for introducing self-control enhancement interventions in both childhood and adolescence in what they called a "one-two punch". "... [I]nterventions in adolescence that prevent or ameliorate the consequences of teenagers' mistakes might go far to improve the health, wealth and public safety of the population," they said. "On the other hand, that childhood self-control predicts adolescents' mistakes implies that early childhood intervention could prevent them."

Because the link between childhood self-control and adult outcomes held across the full range of self-control scores, the researchers further recommended introducing universal, rather than targeted, intervention programmes - doing so would help reduce stigma, they said, and could provide benefits even to those who already score highly in self-control.

This study chimes with Walter Mischel's findings when he tracked down the participants from his classic marshmallow research. Those young children who were better able to resist the allure of a cookie or marshmallow grew into teenagers with fewer disciplinary problems and better school results.
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Moffitt, T., Arseneault, L., Belsky, D., Dickson, N., Hancox, R., Harrington, H., Houts, R., Poulton, R., Roberts, B., Ross, S., Sears, M., Thomson, W., and Caspi, A. (2011). From the Cover: A gradient of childhood self-control predicts health, wealth, and public safety. Proceedings of the National Academy of Sciences, 108 (7), 2693-2698http://dx.doi.org/10.1073/pnas.1010076108

From the BPS research digest