The art of children, psychiatric patients and prisoners who create art outside conventional structures of art training and art production is often categorised as outsider art. In 1964 the French artist Jean Dubuffet started to collect artworks he considered to be free from societal constraints. This was termed art brut (raw art) – another term for outsider art – and in 1948 he founded the Compagnie de L’Art Brut with André Breton.

The artist Ben Nicholson discovered the naïve painter Alfred Wallis in St Ives in the 1920s. A retired fisherman, Wallis painted pictures of ships and the town harbour on pieces of driftwood and cardboard.