Objective: Spot the single changing object as fast as you can while two versions of a scene flicker back and forth.
How it works:
- The scene alternates between version A and version B, with a brief gray flash in between
- Exactly one object differs between the two versions — its color changes, its shape changes, or it appears and disappears
- Click the changing object the moment you spot it; your detection time is recorded for each round
- Clicking the wrong object counts as an error, so only click when you're confident
- If you really can't find the change, use the Skip button — that round is recorded as not found
Why is this hard?
- The gray flash between the scenes wipes out the visual motion signal that would normally make a change "pop out" — this phenomenon is called change blindness
- Without that motion cue, you have to search the scene and compare it from memory, one region at a time
- More objects make the search dramatically harder, and appear/disappear changes are often the hardest of all
Tips:
- Scan the scene systematically — for example, left to right, row by row — rather than jumping around
- Try holding your gaze on one region across several flickers before moving on