[sente]

I'm probably just being overly critical here but his example of "deciding if a number is odd or even in a matter of seconds" seems odd, I think 2nd graders and up can tell you in half a second or less whether or not a number's even or odd.

He says:

"In addition to working memory, researchers are seeking to improve fluid intelligence by training other basic mental skills — perceptual speed (deciding, in a matter of seconds, whether a number is odd or even), visual tracking (on a shoot-’em-up computer game, for instance) or quickly switching between a variety of tasks."

http://i.imgur.com/k9PXE.png

[gwern]

> can tell you in half a second or less whether or not a number's even or odd.

Sure, but just because it takes half a second or less doesn't mean it's not reflecting mental performance. For example, testing reflexes takes even less time, down to tenths of a second, but yet, reflex time still correlates with IQ.