Wednesday, January 04, 2012

What Does IQ Measure?

I have more than once said that nobody knows what (biological substrate) IQ tests measure, only that they have high consistency, at least over short intervals.  There is another sense in which we know exactly what they measure: speed and skill in solving a wide variety of cognitive problems.  Those cognitive problems usually encompass verbal, mathematical, spatial, and pattern recognition tasks.  Skill (and speed) at each of these tasks is known to be teachable, at least in part.

Why then, should there be this prejudice that IQ is not teachable?  Mostly, I think, because those skills can't be taught quickly.  No one becomes a chess master in 1 or even 100 lessons, and no one acquires a large functional vocabulary without years of reading and writing.  So, if IQ measures one's teachability and is itself teachable, does that just mean there is nothing there but education?  Probably not.  We differ in reaction time, working memory, and our ability to convert working memory to permanent memory, and it doesn't seem that those things are greatly affected by practice.

It seems possible, or perhaps even likely, that intrinsic differences beyond the reach of education exist.  But its also likely that the usual results of IQ tests are only rather indirect measures of those intrinsics.