Q. How large is the human cortex?

A. I assume you are referring to the cerebrum or gray matter, the portion of the brain where higher cognitive functions take place. According to The Human Mind Explained: a rat’s cortex is the size of a postage stamp; a monkey’s the size of an envelope, a chimpanzee’s the size of a sheet of typing paper; the human cortex the size of four sheets. However, the cortex of an elephant is four times as large as that of a human’s, while that of a whale is six times greater. But the human cortex is much larger in relation to the size of the body. This larger cortex to body ratio in humans is supposed to be a sign of intelligence....