Angle Precision
A clinical measure of visuospatial precision and fine motor control. Drag to rotate a line to be exactly parallel to a reference line. Your error in degrees determines your rank.
Visuospatial Orientation Accuracy
Rotate the line to match · 5 seconds per round
5 rounds · average error in degrees · lower is better
01 /How to Play
- A reference line will appear at a fixed angle on screen.
- A second line starts at a random angle — drag or use the slider to rotate it.
- Try to make both lines exactly parallel.
- Click Submit when you are satisfied with your alignment.
- Complete 5 rounds — your average error in degrees across all rounds is your final score.
02 /The Science
Visuospatial orientation judgment relies on the right parietal cortex, particularly the superior parietal lobule, which maintains an internal model of spatial relationships. The precision of angle discrimination follows Weber's Law at small angles. Architects, surgeons, pilots, and artists consistently outperform average populations on spatial orientation tasks. Fine motor control for precise rotational adjustment recruits the cerebellum's error-correction circuits, making this task a combined measure of perceptual acuity and motor precision.
03 /Pro Tips
- Step back from the screen — peripheral vision integrates angles more holistically than foveal vision.
- Use small increments near your target — overshoot and correct rather than stopping short.
- Anchor your estimate to the nearest horizontal or vertical — cardinal directions are easiest.
- Close one eye to eliminate binocular depth cues that can distort angular perception.
- Relax your wrist before adjusting — muscle tension creates micro-tremors.