Hans Prinzhorn was a psychiatrist and art historian who had worked with Emil Kraepelin at the University of Heidleberg on a collection of art by mentally disturbed patients. By 1921, when Prinzhorn left Heidleberg, this collection had grown to include over 5000 works by about 350 patients. Prinzhorn’s 1922 book Artistry of the Mentally Ill (profusely illustrated with images from the Heidelberg collection), was the first attempt to analyse this type of art, that subsequently became known as ‘Outsider Art’. Prinzhorn was interested in the borderline between psychiatry and art, mental illness and self-expression, and his work became very influential among artists, especially the Expressionists and Surrealists, with their interest in self expression and in visualising the working of the unconscious mind.

As most serious artists and designers are interested in the act of perception and cognition – the way we transmute the visual and other sensual input from the outside world into mental images – and how we then illustrate these images and evoke them with works of art, Prinzhorn’s book stands out as the first major study to analyse these issues. Of course we know much more now of the workings of the brain, and have begun to develop coherent theories of the Mind (see for example Marvin Minsky’s Society of Mind, and Daniel Dennet’s Consciousness Explained), but the issues addressed by Prinzhorn are still central to these developments. ‘Outsider Art’ is the label now used to describe the art of the mentally ill, the ‘naive’ work of untrained ‘folk artists’, the work of so-called primitive tribes and other similar artefacts, and remains a source of inspiration for artists, nor merely in the radically unconventional images that are produced by ‘outsiders’ but as evidence of these process of perception, cognition and expression that are central to all our experiences of art and design.

Other good books on this subject: Steven Rose: From Brains to Consciousness, Igor Aleksander: How to Build a Mind, and Margaret Boden: The Creative Mind.