Type 3: Ambiguous Figures 🟡 Medium
All is Vanity (Skull or Women)
A classic bistable drawing from 1892. At a distance, it is a giant skull; up close, it is two girls sitting at a vanity table.
👁️
👁️ WHAT TO LOOK FOR: Stare at the image. Squint your eyes or stand back to perceive the skull structure. Toggle the controls to highlight the skull contours or the outline of the two seated girls.
This illusion uses a fixed display for accuracy.
🎮 EXPERIENCE IT FIRST
Observe how your brain resolves this visual ambiguity:
- Squint your eyes or walk back a few steps. Notice how the details of the dresses and vanity table merge into the teeth and jaws of the skull.
- How does the candle flame in the center function? In the skull interpretation, it serves as the bridge of the nose; in the scene, it's a candle on the vanity.
- Notice how spatial frequency determines which image dominates. High spatial frequencies (up close) reveal details of the women. Low spatial frequencies (far away) reveal the skull.
🧠 THE SCIENCE
Charles Allan Gilbert's "All is Vanity" is a classic example of a bistable illusion based on spatial frequency filtering. In the human visual system, details are processed in parallel pathways depending on how close or far apart the visual cycles are. High-spatial-frequency pathways (processed by parvocellular pathways in the LGN) carry sharp borders, fine details, and color. Low-spatial-frequency pathways (processed by magnocellular pathways) carry coarse outlines, shadows, and motion cues.
When you stand close to the drawing, your visual cortex has access to high spatial frequencies. This allows the LOC (lateral occipital complex) to group the lines into two distinct women facing each other, looking at mirrors on a table. The white background represents the window/table, and the details of the dresses are highly visible.
However, when you stand far away, or squint your eyes, the high-spatial-frequency details are filtered out. The visual cortex is left with only low-frequency components: the dark shadows of the women's dresses merge into the eye sockets of a skull, and the table outline forms the teeth row. The brain, attempting to recognize a cohesive structure, resolves this coarse outline as a giant skull.
This demonstrates that object recognition is an active predictive process: the brain applies semantic filters to group visual elements based on spatial constraints. Because the skull and scene are mutually exclusive interpretations of the same visual space, they compete in the visual cortex, flipping back and forth as neural populations adapt.
💡 FUN FACTS
- • "All is Vanity" is a double-entendre referring both to the vanity table where the women sit and the biblical concept of vanity (memento mori).
- • Charles Allan Gilbert was only 18 years old when he drew this masterpiece in 1892.
- • It was sold to Life magazine in 1902 and quickly became a global sensation in visual science.
🧪 TRY THIS AT HOME
Try looking at the image on your phone, then move the phone slowly away from your eyes. Pinpoint the exact distance where the women disappear and the skull takes over.
📜 DISCOVERER
Discoverer: C. Allan Gilbert (1892)
Charles Allan Gilbert was an American illustrator who pioneered using bistable vanity scenes as vanity/death allegories, a theme that has since been adapted by Salvador Dalí and other surrealist artists.