In your example, we have no reason to privilege the hypothesis that there is an underlying causal factor behind that data. In the case of g, wouldn’t its relationships to neurobiology be a reason to give a higher prior probability to the hypothesis that g is actually measuring something real? These results would seem surprising if g was merely a statistical “myth.”
In the case of g, wouldn’t its relationships to neurobiology be a reason to give a higher prior probability to the hypothesis that g is actually measuring something real?
The best evidence that g measures something real is that IQ tests are highly reliable, i.e. if you get your IQ or g assessed twice, there’s a very good correlation between your first score and your second score. Something has to generate the covariance between retestings; that g & IQ also correlate with neurobiological variables is just icing on the cake.
To answer your question directly, g’s neurobiological associations are further evidence that g measures something real, and I believe g does measure something real, though I am not sure what.
These results would seem surprising if g was merely a statistical “myth.”
Shalizi is, somewhat confusingly, using the word “myth” to mean something like “g’s role as a genuine physiological causal agent is exaggerated because factor analysis sucks for causal inference”, rather than its normal meaning of “made up”. Working with Shalizi’s (not especially clear) meaning of the word “myth”, then, it’s not that surprising that g correlates with neurobiology, because it is measuring something — it’s just not been proven to represent a single causal agent.
Personally I would’ve preferred Shalizi to use some word other than “myth” (maybe “construct”) to avoid exactly this confusion: it sounds as if he’s denying that g measures anything, but I don’t believe that’s his intent, nor what he actually believes. (Though I think there’s a small but non-negligible chance I’m wrong about that.)
In your example, we have no reason to privilege the hypothesis that there is an underlying causal factor behind that data. In the case of g, wouldn’t its relationships to neurobiology be a reason to give a higher prior probability to the hypothesis that g is actually measuring something real? These results would seem surprising if g was merely a statistical “myth.”
The best evidence that g measures something real is that IQ tests are highly reliable, i.e. if you get your IQ or g assessed twice, there’s a very good correlation between your first score and your second score. Something has to generate the covariance between retestings; that g & IQ also correlate with neurobiological variables is just icing on the cake.
To answer your question directly, g’s neurobiological associations are further evidence that g measures something real, and I believe g does measure something real, though I am not sure what.
Shalizi is, somewhat confusingly, using the word “myth” to mean something like “g’s role as a genuine physiological causal agent is exaggerated because factor analysis sucks for causal inference”, rather than its normal meaning of “made up”. Working with Shalizi’s (not especially clear) meaning of the word “myth”, then, it’s not that surprising that g correlates with neurobiology, because it is measuring something — it’s just not been proven to represent a single causal agent.
Personally I would’ve preferred Shalizi to use some word other than “myth” (maybe “construct”) to avoid exactly this confusion: it sounds as if he’s denying that g measures anything, but I don’t believe that’s his intent, nor what he actually believes. (Though I think there’s a small but non-negligible chance I’m wrong about that.)