Salvador Dalí

Salvador Dalí (1904–1989) is remembered as one of the twentieth century's most flamboyant public figures and one of its most technically skilled painters. A strand of his work also belongs in any account of ambiguous images. Trained in classical technique at the Real Academia de Bellas Artes de San Fernando in Madrid before joining the Surrealists in Paris in the late 1920s, Dalí could paint dreamlike, contradictory scenes with photographic conviction. That skill is what made his double images work: both readings look equally real.

The paranoiac-critical method

Dalí named his approach the "paranoiac-critical method": deliberately cultivating a state in which one thing suggests another, then painting what emerged with complete control (Ades, 1982). In practice it often produced paintings with two readings in a single composition. In Slave Market with the Disappearing Bust of Voltaire (1940), two women in black and white dresses standing in an archway also form the eyes, nose and chin of a bust of the philosopher Voltaire. In Swans Reflecting Elephants (1937), three swans and their reflections in a lake become three elephants, the swans' necks doubling as trunks.

He meant these as deliberate explorations of how one arrangement of forms can support several incompatible interpretations, an artistic counterpart to the reversible figures psychologists study, such as the duck-rabbit and the "my wife and my mother-in-law" drawing.

Lincoln at twenty metres

Dalí also read about vision science. In 1973, the Bell Labs researcher Leon Harmon published an article in Scientific American on how people recognise faces, illustrated with a portrait of Abraham Lincoln reduced to a coarse grid of grey squares (Harmon, 1973). Close up it's just blocks; seen from a distance, or with your eyes half closed, Lincoln appears, because the blocks still carry the broad pattern of light and dark that the visual system uses to recognise a face. Dalí turned the idea into a painting, Gala Contemplating the Mediterranean Sea which at Twenty Meters Becomes the Portrait of Abraham Lincoln, made in two versions between 1974 and 1976. Up close it shows his wife Gala looking out of a window made of coloured squares; from across a room, the squares become Lincoln's face.

Not quite the same as a lab figure

Dalí's double images aren't the same as the figures on this site's ambiguous pages. Rubin's vase and the duck-rabbit are stripped down so that the two readings are as evenly balanced as possible. Dalí's hide a second image inside a rich, detailed scene, closer to a hidden-picture puzzle. What links them is the mechanism: the visual system organises ambiguous information into one interpretation at a time, and once you've found the second reading, the picture flips. His work shows that the same features of vision psychologists demonstrate with line drawings can carry ambitious paintings.