The emergence of cave drawings c40,000 years ago is explained as an ‘external hard-drive’, alleviating biological constraints on brain capacity by preserving shareable information about predators and prey necessary for survival during a period of expanding social networks, ultimately leading to humans becoming the globally-dominant species. Theories of visual perception, fundamental to any pedagogy of drawing, are reviewed. Modes of visual ‘attention’ are discussed, defining the difference between ‘focused’ and ‘distributed’, and relating both to intentional communication through drawing, the progenitor of writing. The article argues that drawing facilitates an intelligence of seeing, a visualcy, as important as literacy and numeracy at all levels of the educational curriculum. A pedagogy of drawing is proposed, illustrated with examples.