Watch the flickering scene. What do you notice?
Watch the scene carefully. It alternates between two versions with a brief grey flicker between them. One thing changes between the versions, but the flicker makes it hard to spot.
When you think you have found the change, click "Reveal Change" to confirm. Click "Next Scene" to try another puzzle.
Normally, when something changes in our visual field, the motion signal (the transient) grabs our attention instantly. But the grey flicker creates a global transient that masks the local change, leaving your visual system unable to distinguish where the change occurred.
Without the motion signal, you must search the image piece by piece using focused attention — a slow process for a scene with many objects.
Change blindness suggests that our sense of rich, detailed visual awareness may be partly illusory. We feel as though we see everything, but experiments like this show we actually sample the world sparsely, attending to only a few things at a time.
Our sense of visual completeness is a construction - a "just-in-time" strategy where details are fetched from the world as needed, rather than stored in some internal picture. Consciousness presents an illusion of richness that the underlying mechanisms cannot support.