Salvador Galo Anselmo Dalí i Domènech was born to Felipa Domènech i Ferrés and Salvador Dalí i Cusí on October 12, 1901, in the town of Figueres in Catalonia, Spain. The couple's firstborn child, he showed signs of great precociousness, but his potential was tragically cut short. Little Salvador fell sick with gastroenteritis and died just two months shy of his second birthday. His parents were devastated but, in their grief, conceived another child. On May 11, 1904, only nine months and 10 days after the death of their son, a second boy entered this world. His name? Also Salvador.

It was this Salvador—middle names, Felipe Jacinto—who would become one of the most important artists of the 20th century. In his mind, however, he was forever in the shadow of his sibling. The two Salvadors shared an uncanny likeness. “When my father looked at me, he was seeing my double as much as myself,” Dalí later reflected.

Not creeped out yet? Read on.

When Dalí was five years old, his parents took him to his brother's grave and told him that he was his reincarnation. The idea took hold and haunted Dalí's days. “[We] resembled each other like two drops of water, but we had different reflections,” he once wrote. “My brother was probably a first version of myself but conceived too much in the absolute.” This belief had a profound impact on his art. His paintings prominently feature doublings, as in his Portrait of My Dead Brother (1963) above, which features a composite of the artist and his sibling.

Dalí created many visual illusions by overlaying images made of sharp contours and small details—so-called high spatial frequencies—with images made of soft contours and bigger details—or low spatial frequencies—all in the same ambiguous scene. As a result, viewers perceive one or the other image, depending on how close they are to the painting. Up close, the details from the high spatial frequency image dominate. But when viewers squint their eyes or look at the painting from far away, the other picture appears. A detailed inspection of Dalí's Portrait of My Dead Brother, for instance, reveals that the larger face is made of what appear to be dark and light cherries, sometimes paired as twins. Step back, though, and the picture of a young man emerges, with a crow or vulture embedded in his forehead and doubling as hair.

Neuroscientist Aude Oliva and her colleagues at the Massachusetts Institute of Technology have optimized this type of perceptual switch in several striking examples. One such image (opposite page at top) looks like two eagles up close but becomes a head and neck seen from afar.

Last year we served as scientific consultants for the Marvels of Illusion exhibit at the Dalí Museum in St. Petersburg, Fla. The collection of artwork showcased the role of illusions in Dalí's art and featured numerous examples of dual interpretations and doubling. “Dalí intuited that what we construe visually as reality is the product of the habits of the mind, more than of the eye,” says Hank Hine, the museum's executive director. “By creating accessible double images, Dalí asks us to reconsider on a fundamental scale our constructs of reality.”

Here we present a few of Dalí's double paintings included in the exhibit to discuss their perceptual mechanisms.

Just as Dalí saw himself as a less “absolute” copy of his older brother, a number of his paintings re-create and reinterpret previous works by the old masters, such as Raphael, Velázquez and Rembrandt. The results are eminently ambiguous: the old composition lingers just below the surface of Dalí’s version.

The Madonna of the Birds watercolor (1943) (right) is based on, and preserves, the original arrangement of Alba Madonna, circa 1510, by Raphael (1483–1520) (left). The sandal on the Virgin’s left foot is a close replica of Raphael’s original, whereas the torso is merely hinted at in Dalí’s reimagining. Cortical neurons in the viewer’s brain connect the individual birds to suggest the contours of the Virgin’s head and face. CREDIT: CORBIS


In the 1930s Dalí developed what he called the paranoiac-critical method, which relied on his ability to establish connections between seemingly unrelated concepts or images. In Paranoia (1935–1936), a battle scene resembling a Leonardo da Vinci sketch hovers over a silvery, headless female bust, set on a loosely drawn pedestal. Small figures of warriors and horses form parts of the woman's face: eyes, mouth, chin and hairline. Most of her features are absent, but the viewer's visual system fills them in.

Such filling-in processes are common in everyday perception. Face-detecting neurons in the brain's fusiform gyrus area in the temporal lobe are particularly predisposed to detecting the human visage, however vague or ambiguous. This is why we often see the fronts of cars as faces, with the grilles as mouths and the headlights as eyes.

To see the woman's face more clearly, try squinting your eyes to blur the edges of the little figures. The face itself has two different interpretations: some people see a kind lady lowering her gaze to her right, whereas others see a crazed woman with a scary smile. CREDIT: AUDE OLIVA Massachusetts Institute of Technology AND AMANDA O'KEEFE