The Cognitive Link between Geography and Development: Iodine Deficiency and Schooling Attainment in Tanzania

64 Pages Posted: 28 Mar 2008 Last revised: 25 Apr 2021

See all articles by Erica Field

Erica Field

Duke University, Fuqua School of Business-Economics Group; Duke Innovation & Entrepreneurship Initiative

Omar Robles

Harvard University - Faculty of Arts and Sciences

Maximo Torero

International Food Policy Research Institute (IFPRI); International Food Policy Research Institute (IFPRI)

Date Written: March 2008

Abstract

An estimated 20 million children born each year are at risk of brain damage from in utero iodine deficiency, the only micronutrient deficiency known to have significant, non-reversible effects on cognitive development. Cognitive damage from iodine deficiency disorders (IDD) has potentially important implications for economic growth through its effect on human capital attainment. To gauge the magnitude of this influence, we evaluate the impact of reductions in fetal IDD on child schooling attainment that resulted from an intensive distribution of iodized oil capsules (IOC) in Tanzania. We look for evidence of improvements in cognitive ability attributable to the intervention by assessing whether children who benefited from IOC in utero exhibit higher rates of grade progression at ages 10 to 14 relative to siblings and older and younger children in the district who did not. Our findings suggest that reducing fetal IDD has significant benefits for child cognition: Protection from IDD in utero is associated with 0.36 years of additional schooling. Furthermore, the effect appears to be substantially larger for girls, consistent with new evidence from laboratory studies indicating greater cognitive sensitivity of the female fetus to maternal thyroid deprivation. There is no indication that IOC improved rates of illness or school absence due to illness, suggesting that IOC improves schooling through its effect on cognition rather than its effect on health. However, there is weak evidence that the program also reduced child but not fetal or infant mortality, which may bias downward the estimated effect on education. Cross-country regression estimates corroborate the results from Tanzania, indicating a strong negative influence of total goiter rate and strong positive influence of salt iodization on female school participation. Together, these findings provide micro-level evidence of the direct influence of ecological conditions on economic development and suggest a potentially important role of variation in rates of learning disability in explaining cross-country growth patterns and gender differences in schooling attainment.

Suggested Citation

Field, Erica and Robles, Omar and Torero, Maximo and Torero, Maximo, The Cognitive Link between Geography and Development: Iodine Deficiency and Schooling Attainment in Tanzania (March 2008). NBER Working Paper No. w13838, Available at SSRN: https://ssrn.com/abstract=1104175

Erica Field (Contact Author)

Duke University, Fuqua School of Business-Economics Group ( email )

Box 90097
Durham, NC 27708-0097
United States
(919) 660-1857 (Phone)

HOME PAGE: http://sites.duke.edu/ericafield/

Duke Innovation & Entrepreneurship Initiative ( email )

215 Morris St., Suite 300
Durham, NC 27701
United States

Omar Robles

Harvard University - Faculty of Arts and Sciences ( email )

1875 Cambridge Street
Cambridge, MA 02138
United States

Maximo Torero

International Food Policy Research Institute (IFPRI) ( email )

1201 Eye St, NW,
Washington, DC 20005
United States

International Food Policy Research Institute (IFPRI) ( email )

1201 Eye St, NW,
Washington, DC 20005
United States

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