Tail effects

From Emil Kirkegaard‘s website,

Tail effects are when there are large differences between groups at the extremes (tails) of distributions. This happens when the distributions differ in either the mean or the standard deviation (or both), even when these differences are quite small.

A nifty interactive visualization to explore tail effects can be found here.


More on the BMW Syndrome

Newton famously lost his shirt in the South Sea Bubble. How could he, of all people, fall for this rather obvious swindle? Well, many highly intelligent people seem rather gullible.

Highly intelligent people are good at recognizing patterns in IQ tests and presumably in real life. Possibly they get more false positives than less intelligent people; they sometimes recognize patterns where no patterns exist.

If combined with arrogance and an inability to listen to others, there is no error correction. This agrees well with the observation that highly intelligent, arrogant people tend to go off into imaginary cloud-cuckoo-lands.

The BMW Syndrome

There doesn’t seem to be a name for the this syndrome: highly intelligent, brilliant people with very poor judgment.

Three exemplars are McGeorge Bundy (Bay of Pigs, Vietnam, incidentally almost managed to destroy both Yale’s and the Ford Foundation’s endowments), Robert McNamara (Bay of Pigs, Vietnam), Paul Wolfowitz (Iraq War, nepotism in the World Bank).

Bundy, McNamara, Wolfowitz. The BMW Syndrome?

Do IQ tests measure general intelligence?

On Alpha Psy Hugo reports on an interesting paper (Van Der Maas et al., A Dynamical Model of General Intelligence: The Positive Manifold of Intelligence by Mutualism).

Scores on a wide range of intelligence tests tend to correlate positively. From a statistical or psychometric point of view this creates a variable, g that merely indicates the strength of this correlation. If there were no correlation at all, there would be no g, but since the correlations tend to be high, people get excited and many of them take the next step of positing an underlying common cause (also called g). For the psychologists who defend this notion, there is a common variable (modulating, say, the way your neurons fire) that influences on the measures of all of these intelligence tests, thus creating the observed correlation. However researchers from the University of Amsterdam are challenging the common wisdom and suggest an explanation for the correlation that doesn’t need a common cause.

How important is intelligence? On Dilbert Blog Scott Adams says,

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