Not done Sir, but doing.

Plenty is doing.

"Younger and less intelligent people have been said to have smaller and less elaborately organized knowledge bases; to use fewer, simpler, and more passive processing strategies; to have less metacognitive understanding of their own cognitive systems and of how the functioning of these systems depends upon the environment; and to use less complete and flexible executive processes for controlling their thinking.... Although definitive analyses have not been done, presently used tests of intelligence can be assumed to measure base knowledge and cognitive strategies reliably and validly."

E.C.BUTTERFIELD, 1986, in R.J.Sternberg & D.K.Detterman, What is Intelligence?. Norwood, New Jersey : Ablex.

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.