INTERESTING: How Adding Iodine To Salt Resulted In A Decade’s Worth Of IQ Gains For The United States. “A new NBER working paper from James Feyrer, Dimitra Politi, and David N. Weil finds that the population in iodine-deficient areas saw IQs rise by a full standard deviation, which is 15 points, after iodized salt was introduced. Since one quarter of the population lived in those areas, that corresponds to a 3.5 point increase nationwide. We’ve seen IQs go up by about 3 points every decade, something called the Flynn effect, so iodization of salt may be responsible for a full decade’s worth of increasing IQ in the U.S.”