Moving Illusions

A single still image can look like it’s subtly “boiling” or “waving” because the brain misreads how it should account for the eye’s own movements—an effect called anomalous motion. After a saccade, the brain doesn’t process all parts of a scene at the same speed. Higher-contrast details register sooner than lower-contrast ones, and when the image is arranged to exploit that timing gap, the visual system settles on one wrong explanation: the picture must be moving rather than the perception pipeline being out of sync. Akiyoshi Kitaoka’s “Out of focus” takes the idea further by splitting the image into tiny slices that nearby neurons disagree about after a saccade, making it harder for the brain to factor in what the eyes just did. The result is a convincing illusion of motion created by the brain’s own attempt to stitch perception together.

That same core vulnerability—how perception is assembled from incomplete, delayed signals—shows up far beyond parlor tricks. In nature and warfare, optical illusions become tools. Dazzle camouflage doesn’t hide a ship; it scrambles an enemy’s ability to judge shape, direction, and speed, making the target harder to track. During the Cold War arms race, the Soviet Union’s long-range bomber display used a film trick: the same few aircraft were flown past the camera repeatedly in formations that made it look like far more planes existed. The United States, taking the inflated count at face value, ramped up production—building nearly 2,000 B-52s at enormous cost—while the Soviets actually had only about 150 long-range bombers.

Optical illusions also shape everyday environments and cultural perception. Disney castles rely on forced perspective: the tops appear farther away because they’re actually much smaller. The Müller-Lyer illusion demonstrates that perception isn’t universal. People in Western cultures tend to see the bottom lines as longer, influenced by familiar rules of perspective and straight-edged man-made geometry, while bushmen from Southern Africa and tribespeople from northern Angola and the Ivory Coast are not fooled.

Illusions can even be medical and practical. Kitaoka’s work uses optical illusions to help detect glaucoma earlier than current methods. Anamorphic designs—images that look distorted from most angles but “snap” into clarity from one viewpoint—have been used for traffic safety, including a skewed road decal in West Vancouver, Canada that appears to form a 3D child about to be hit when viewed from a driver’s perspective. Anamorphic techniques have also been used for covert political signaling, such as hidden portraits revealed only when a reflective object is placed correctly on a tray.

Finally, illusions extend into judgment. The “End of History” illusion is the tendency to assume the self today is the final version, even though people consistently underestimate how much they’ll change over time. The illusion of control—named by psychologist Ellen Langer—captures the belief that outcomes depend on one’s actions. In a study with London traders, buttons that had no effect still produced a stronger sense of control, and those who felt most in control performed worse on risk management and earned less. The through-line is sobering: perception and decision-making both rely on shortcuts that can feel convincing—even when they’re wrong.