Iodized salt made Americans smarter

[garbon]

http://news.yahoo.com/new-study--iodized-salt-made-americans-smarter-140609525.html

Iodine appears to have made Americans smarter, the Daily Mail reports.

While the addition of iodine to salt originally was intended to eliminate goiters caused by iodine deficiencies, it appears to have had an unexpected consequence: Americans gained up to 15 IQ points after iodized salt became mandatory in 1924, a new study finds.

The National Bureau of Economic Research recently published a report by economists James Freyer, Dimitra Politi and David Weil that looked at intelligence data from roughly 2 million World War II enlistees born between 1921 and 1927.

The study, which compares the IQ levels of recruits born before 1924 with those born after that year, shows that those who ranked the highest were assigned to the Army Air Forces. Meanwhile, those recruits with lower IQ scores were sent to the Army ground forces.

The economists then researched likely iodine levels in recruits' hometowns based on the occurrence of goiters in those regions, and they discovered that recruits born in low-iodine areas after 1924 were much more likely to be sent to the Army Air Forces than those recruits born before 1924. In fact, the average IQ of those slightly younger recruits was 15 points higher than that of older recruits.

According to the report, the addition of iodine to salt might be one cause behind the Flynn effect, a long-sustained rise in IQ from roughly 1930 to the present.

[Caliga]

 

Hm.... doesn't this also suggest that people who lived in coastal areas would have been smarter than people who lived inland, assuming they ate a lot of fish as part of their diet?

[Neil]

You know, it's also possible that, for some reason, in 1942 the Army started recruiting from a much broader base than they did prior to that.  I wonder what could have happened in late 1941 to cause bright young men to enlist in the army?

[Caliga]

This reminds me of a map I saw once that tried to give each nation an IQ score, I think based on the average estimated IQ of its citizens.  IIRC China and Japan had the highest scores, and there were some nations in sub-Saharan Africa where the average IQ was in the mentally retarded range.

[The Minsky Moment]

I wonder what could have happened in late 1941 to cause bright young men to enlist in the army?

I can't quite recall, but I think it involved John Belushi somehow.

[Jacob]

You know, it's also possible that, for some reason, in 1942 the Army started recruiting from a much broader base than they did prior to that.  I wonder what could have happened in late 1941 to cause bright young men to enlist in the army?

While that is true that something might have happened in 1941 to change recruiting patterns in 1942, the article and study seems primarily concerned with the changes in 1924; 18 years prior to 1942.

[Caliga]

Neil, please eat some salt.

[Maximus]

This reminds me of a map I saw once that tried to give each nation an IQ score, I think based on the average estimated IQ of its citizens.  IIRC China and Japan had the highest scores, and there were some nations in sub-Saharan Africa where the average IQ was in the mentally retarded range.

Intelligence is highly subjective. It can be useful to try to measure for a specific task or related set of tasks(ie executive skills), but trying to reduce general intelligence to a scalar is a fool's game.

[DGuller]

You know, it's also possible that, for some reason, in 1942 the Army started recruiting from a much broader base than they did prior to that.  I wonder what could have happened in late 1941 to cause bright young men to enlist in the army?

While that is true that something might have happened in 1941 to change recruiting patterns in 1942, the article and study seems primarily concerned with the changes in 1924; 18 years prior to 1942.

It is concerned with changes in people born in 1924.  When would they be recruited? 

[Caliga]

Ouch.  You're good, Neil.  Jacob, please eat some salt.

[Caliga]

Intelligence is highly subjective. It can be useful to try to measure for a specific task or related set of tasks(ie executive skills), but trying to reduce general intelligence to a scalar is a fool's game.

I was just mentioning that I'd seen it.  I place very little value in IQ personally.  It seems to not have much correlation with success in life so I'm not sure what value it actually has.

[Valmy]

I was just mentioning that I'd seen it.  I place very little value in IQ personally.  It seems to not have much correlation with success in life so I'm not sure what value it actually has.

Really?  You know lots of really successful people with 75 IQs?

[DGuller]

This reminds me of a map I saw once that tried to give each nation an IQ score, I think based on the average estimated IQ of its citizens.  IIRC China and Japan had the highest scores, and there were some nations in sub-Saharan Africa where the average IQ was in the mentally retarded range.

Mentally retarded IQ range is just a proxy.  If you have an IQ that's more that two standard deviations below the average, you probably have some handicap that causes both the relatively low IQ and the observable signs of retardation.

[garbon]

From the daily mail article

http://www.dailymail.co.uk/news/article-2377052/How-adding-iodine-salt-America-smarter.html

The World Health Organization estimates that two billion people worldwide are at risk of iodine deficiency.
And it's not just a Third World problem - the WHO reports that only 27 per cent of households in Europe have access to iodized salt.

[Caliga]

Really?  You know lots of really successful people with 75 IQs?

I don't know anyone who claims to have an IQ that low.