Are some people simply more visual than others? And, what do we reveal through our drawings? Drawing is something we all do unselfconsciously as children before we learn to write. It is a form of expression that goes back 40,000 years and began on the walls of caves. But why do we draw? Is it to make our mark on the world, to decorate our surroundings, or is it a way of communicating with others when words fail us?

Lucy Ash talks to Stephen Wiltshire, world famous for his incredibly detailed pen and ink cityscapes; to Rebecca Chamberlain, a psychologist now at the University of Leuven in Belgium who is studying art school students to try and understand how people get better at drawing; to David Hockney renowned for his both his traditional draughtsmanship and his enthusiasm for new technology and to Lizzie Ellis, who comes from a remote community in central Australia and draws with a stick, telling stories through her traditional form of Aboriginal women's art. And at the London charity Kids Company, Arts manager Jebet Mengech encourages children to express themselves with pencils, crayons and felt tips using drawing to reveal problems in the children’s lives.

(Photo: A student in a life class at the Royal School of Drawing)