Rapid Scan
A clinical measure of visual search efficiency and pre-attentive processing. A single target character hides among hundreds of distractors — find it as fast as possible. Density increases each round.
Visual Search Efficiency
Find the Q among the O's · 60 seconds total
Grid grows each round · wrong click = game over
01 /How to Play
- The screen fills with a grid of identical O characters.
- One Q is hidden somewhere in the grid — find it and click it as fast as possible.
- Each successful round increases the grid density.
- Your score is the number of rounds completed.
- Clicking the wrong character ends the test immediately.
02 /The Science
Visual search tasks distinguish between pre-attentive and attentive processing. When targets share features with distractors (as in Q-among-O), search requires serial attentive scanning — reaction time scales linearly with distractor count. The Q-in-O task engages feature conjunction search, requiring the visual system to combine information about curvature and the presence of a tail. This recruits the frontal eye fields and parietal cortex in a coordinated top-down attention sweep.
03 /Pro Tips
- Don't scan systematically — let your eyes roam freely. Pre-attentive processing works best with distributed attention.
- Slightly blur your focus — the Q tail becomes more salient in peripheral vision.
- Scan in a loose Z-pattern to maximize grid coverage efficiently.
- Increase screen brightness — higher contrast makes the subtle Q-tail more detectable.
- Avoid fixating on individual characters — move your gaze in large jumps.