SEE THE DIFFERENCE · 20 TRIALS
Choose the side with the visually larger object before time runs out.
Complete 20 timed comparisons. Mistakes and timeouts count, then play continues.
READY?
Press Left Arrow or A for LEFT. Press Right Arrow or D for RIGHT.
Keyboard: ← / A for left · → / D for right. Touch: tap a labeled button.
HOW TO PLAY
Start the game and look at the two matching shapes.
Choose LEFT or RIGHT according to which object is physically larger.
Finish all 20 standard trials, or protect your endless streak as the differences and deadlines shrink.
VISUAL SIZE JUDGMENT
Each trial asks you to detect a visible size difference between two otherwise matching objects and convert that judgment into a directional response.
Shape type changes, but both objects in a pair always share the same geometry and styling. There are no equal-size trick trials.
READ YOUR RESULT
Standard mode contains exactly 10 left-larger and 10 right-larger trials. Later groups use smaller—but still visible—size differences.
This is a recreational browser game, not a clinical test. Screen size, device latency, input method, vision, and practice can affect results.
QUESTIONS
No. Every trial has one clearly larger object. The size gap narrows with difficulty but never falls below a visible minimum.
In standard mode it counts as incorrect and the next trial begins. In endless mode, one wrong answer ends the run.
A timeout is recorded once. Standard mode continues to the next trial; endless mode ends immediately.
Yes. Use the two large touch buttons on phones and tablets. Desktop players can also use arrow keys or A and D.