Classic Titchener Circles
Which ORANGE circle is larger?
Match the Centers
Control the Surroundings
Make both surrounding sizes equal—watch the illusion DISAPPEAR! The center circles are always 30px.
Surround Distance
Size Perception Game
Which CENTER circle is ACTUALLY larger? Ignore the surroundings!
Animated Illusion
Watch the center circles appear to PULSE as the surrounding circles change size—even though centers never change!
Beyond Circles
The illusion works with ANY shapes—not just circles! The brain compares relative sizes.
Real-World Applications
Food & Diet
Food on a large plate looks smaller, so you serve more. The Delboeuf illusion (related) shows that plating matters for portion control. Use smaller plates to eat less!
Web Design
Buttons surrounded by whitespace look larger and more clickable. Designers use the Ebbinghaus effect to draw attention to call-to-action elements.
Fashion
Wearing patterns with large elements makes the wearer look smaller relative to the pattern. Stylists use this to create slimming or enlarging effects.
Architecture
Rooms with large furniture feel smaller. Interior designers balance object sizes to manipulate perceived room dimensions.
The Psychology of Relative Size
The Ebbinghaus Illusion (also called Titchener Circles) was discovered by German psychologist Hermann Ebbinghaus in the 1890s and popularized by Edward Titchener. It demonstrates that perceived size depends heavily on context.
The "Contrast" Theory: Your visual system doesn't measure absolute size—it compares objects to their surroundings. A circle surrounded by large circles looks small BY CONTRAST. Surrounded by small circles, the same circle looks large. This relative encoding is efficient but can be fooled.
The "Contour Interaction" Theory: Nearby contours interfere with size perception. Large surrounding circles push their "influence" onto the central circle, shrinking it perceptually. Small surrounding circles have less influence, allowing the center to "expand."
Cross-Cultural Differences: The Ebbinghaus illusion affects people worldwide but with different strengths. Some studies show Westerners experience it more strongly than East Asians, possibly due to differences in holistic vs. analytic visual processing styles.
Historical Note
Hermann Ebbinghaus (1850-1909) is best known for discovering the "forgetting curve" and pioneering experimental memory research. The size illusion bearing his name was just one of many perceptual phenomena he explored. Edward Titchener later popularized it in his influential textbooks, which is why it's often called "Titchener circles" in English-speaking countries.