What this test measures
Two nearly identical versions of a simple scene alternate, with a brief blank screen between them. One object differs between the versions - a different colour, a different size, or circle versus square. You click it as soon as you spot it.
Your score is the median time to detection across five trials. Lower is better. A trial you never solve is capped at 30 seconds.
How to get a clean score
- Do not stare at the centre. Move your attention deliberately around the scene, object by object.
- Hold each object in mind across the blank and check whether it looks the same when it comes back.
- Colour changes are usually easiest, shape changes hardest. Expect variation.
How to improve your score
Have a system. Instead of letting your eyes wander, scan the scene in a fixed order - left to right, top to bottom - and on each object ask “is this the same as last cycle?” before moving on. Because attention is what makes a change visible here, a methodical sweep beats a hopeful stare almost every time. It also helps to widen your focus slightly rather than fixating, so more of the scene updates in your peripheral vision. Practice produces a genuine speed-up on this task.
What the number tells you
Change blindness reveals how little of a scene we actually hold in detail at any moment. Faster detection reflects more efficient visual scanning and comparison, skills that matter for proofreading, radiology, driving and any task that involves spotting what is different.