Charles Baudelaire

It is only when you watch the dense mass of thousands of ants, crowded together around the Hill, blackening the ground, that you begin to see the whole beast, and now you observe it thinking, planning, calculating. It is an intelligence, a kind of live computer, with crawling bits for its wits.

I can well imagine that certain writers, even writers that we'd consider today very great writers, may not necessarily have tested highly on IQ just because of their numerical skills, or maybe they may not be very good at memory, and are not particularly good at these kinds of tests.