Plenty is doing.
"Recent research on the relationship between brain volume (measured via magnetic resonance imaging, or MRI) and IQ has indicated a moderate positive correlation of about .40 between the two variables. The purpose of the present research is to further replicate this finding in a sample of 100 healthy adult males comprising 50 pairs of brothers...In 62 subjects (31 pairs of brothers) collected to date, it was found that brain volume correlated significantly with IQ (r = .277, p < .05...."
Disclaimer: this quote appears here only to spark discussion. It is not endorsed one way or the other. Make up your own mind. Or just refresh the page for another viewpoint. From a collection assembled by the late Chris Brand.