On IQ

IQ questions interest me. 100 is supposed to be the average*, but there are loads of different ways of measuring it, many of which give different results for the same person - I have a 20 point differential between two of the sample tests.

IQ is a bit of a pet interest of mine, as an example of a biological statistic that has been mangled and dragged through politics. It is so controversial that many researchers won't even look at intelligence now, and the president of Harvard recently got in extreme PC trouble for even thinking aloud about it.

A few fun facts -

IQ raises on average 5 points if the test is undertaken by someone who has recently listened to Mozart.

It bears little or no correlation to cranial capacity

It is is probably true that IQ is higher in developed than undeveloped countries, which initially seems an incendiary racist argument, until you consider the effect malnutrition and illness have on the brain

The US used to test a sample of immigrants at Staten Island for IQ and concluded that all Russians were congenital morons, due to the minor point of delivering the test in English to starved sleep-deprived refugees

Whichever test method you use, the same distribution difference between men and women can be seen - there are more women of average IQ, but at the highest and lowest ends of the scale there are more men. Women cluster around the average whereas most geniuses and morons are male. Which explains a lot (chess grandmasters, severe regressive autism, GCSE passes) (see here.)

I'd also refer you to Steven J Gould's masterful 'The Mismeasure of Man', a history of political attempts to hijack intelligence studies.

* - 90 or less - certifiable learning difficulty, 125 - average for the holder of a first class degree