The Economic Effects of Micronutrient Deficiency: Evidence from Salt Iodization in the United States

Iodine deficiency is the leading cause of preventable mental retardation in the world today. Iodine deficiency was common in the developed world until the introduction of iodized salt in the 1920’s. The incidence of iodine deficiency is connected to low iodine levels in the soil and water. We examine the impact of salt iodization in the US by taking advantage of this natural geographic variation. Areas with high pre-treatment levels of iodine deficiency provide a treatment group which we can compare to a control group of low iodine deficiency areas. In the US, salt was iodized over a very short period of time around 1924. We use previously unused data collected during WWI and WWII to compare outcomes of cohorts born before and after iodization, in localities that were naturally poor and rich in iodine. We find evidence of the beneficial effects of iodization on the cognitive abilities of the cohorts exposed to it.

The Importance of Graduates for the Scottish Economy: A “Micro-to-Macro” Approach

There have been numerous attempts to assess the overall impact of Higher Education Institutions on regional economies in the UK and elsewhere. There are two disparate approaches focussing on: demand-side effects of HEIs, exerted through universities’ expenditures within the local economy; HEIs’ contribution to the “knowledge economy”. However, neither approach seeks to measure the impact on regional economies that HEIs exert through the enhanced productivity of their graduates. We address this lacuna and explore the system-wide impact of the graduates on the regional economy. An extensive and sophisticated literature suggests that graduates enjoy a significant wage premium, often interpreted as reflecting their greater productivity relative to non-graduates. If this is so there is a clear and direct supply-side impact of HEI activities on regional economies through the employment of their graduates. However, there is some dispute over the extent to which the graduate wage premium reflects innate abilities rather than the impact of higher education per se. We use an HEI-disaggregated computable general equilibrium model of Scotland to estimate the impact of the growing proportion of graduates in the Scottish labour force that is implied by the current participation rate and demographic change, taking the graduate wage premium in Scotland as an indicator of productivity enhancement. We conduct a range of sensitivity analyses to assess the robustness of our results. While the detailed results do, of course, vary with alternative assumptions about future graduate retention rates and the size of the graduate wage premium, for example, they do suggest that the long-term supply-side impacts of HEIs provide a significant boost to regional GDP. Furthermore, the results suggest that the supply-side impacts of HEIs are likely to be more important than the expenditure impacts that are the focus of most “impact” studies.

Competitive Altruism, Mentalizing and Signalling

The human tendency to cooperate with nonkin even in short-run relationships remains a puzzle. Recently it has been hypothesized that altruism may be a byproduct of “mentalizing”, the process of understanding and predicting the mental states of others. Another idea is based on sexual selection: altruism is a costly signal of good genes. The paper shows that these two arguments are stronger when combined in that altruists who can mentalize have a greater advantage over non-altruists when they can signal their type, even though these signals are costly. Further, once such an equilibrium is established, altruists will not be supplanted by mutants who have similar mentalizing abilities but who lack altruism.