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Spatial reasoning

Shepard Mental Rotation

Two 3D-style shapes appear side by side. One may be rotated relative to the other. Decide — as fast as you can — whether they're identical or mirror images.

What makes this one different

We sample rotations across 0°, 60°, 120°, 180° and fit a slope to your reaction times. That slope is your personal rotation rate — how many extra milliseconds per degree of rotation. Most people don't know theirs.

Trial 0 / 24
Mean RT —
Accuracy —
Reference
Match?
Ad slot.

Your rotation rate

How much extra RT each degree of rotation costs you. Lower = better.

— ms/°
Your personal slope from this session

History

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What problem does it solve?

Mental rotation is the canonical spatial-reasoning task. Originally Roger Shepard's 1971 paper, it has been replicated hundreds of times: reaction time scales linearly with the angle of rotation, which is itself a striking finding — your brain doesn't "snap" shapes into alignment, it rotates them through space.

It correlates with math performance, engineering aptitude, and even some sports expertise (chess, dance). It's a clean, well-studied index of spatial cognition.

Who is this for

How to interpret your results

Slope (ms per degree) of 8–15 ms/° is typical for adults. Elite spatial reasoners get into the 4–6 ms/° range. Higher means each degree of rotation costs you more time.

Accuracy above 90% with reasonable RT is healthy. Below 75% suggests you're rushing or the shapes are too hard for current session.

Limitations

  • The classic Shepard task uses specific 7-cube 3D shapes; we approximate with custom 2D-projected L-shapes. The cognitive demand is similar but not identical.
  • We sample 4 angles (0°, 60°, 120°, 180°). Lab studies use more angles for higher-fidelity fits.
  • SVG rendering depends on browser and device. Performance should be consistent within a device.

FAQ

Does practice actually lower the slope?

Modestly. Most people see 10–20% improvement over weeks of regular practice, then plateau. The ceiling is real.

What does a very low slope mean?

You rotate shapes quickly — usually correlated with strong spatial skills. It does not mean you're "smarter overall"; spatial reasoning is one slice.

How do I use Shepard Mental Rotation step by step without mistakes?Follow the order given in the usage section: Judge if two 3D-style shapes match after rotation. We measure your personal rotation-rate slope — how much extra time each degree of rotation costs you. The step-by-step part matters less than the unit check that sits inside it. Confirm every unit matches the thing you are actually trying to measure before you press calculate - that single check catches more wrong answers than any other habit, and it costs about ten seconds.
What are the common mistakes when using Shepard Mental Rotation?Most common mistakes come down to four habits: entering 20 when the field expects 0.2 because the field is a percentage; leaving a field blank and accepting the default without checking what it stands for; changing one input and reading a result that was calculated before the change; and quoting the output as an exact figure when the page describes it as a reference estimate. Press calculate again after any edit, and treat the number as a reference point rather than a final answer.
How do I read the result from Shepard Mental Rotation?Read the final figure first, then come back to this section for the conditions behind it: Slope (ms per degree) of 8–15 ms/° is typical for adults. Elite spatial reasoners get into the 4–6 ms/° range. Higher means each degree of rotation costs you more time. Accuracy above 90% with reasonable RT is healthy. Below 75% suggests you're rushing or the Keep two things apart: the number itself, which comes from the values you typed, and the assumptions it depends on, which decide whether that number is meaningful. The page sets out what a higher or lower result means for your case, so check that direction as well as the magnitude.
Can I act on the Shepard Mental Rotation result directly?Treat it as one reference sheet before you decide, rather than as the answer itself: The classic Shepard task uses specific 7-cube 3D shapes; The output describes a magnitude under the conditions you entered. It does not include what it actually costs to act, what might change while you act, or how the other side behaves. Before you commit, compare the result against reality and note which assumptions do not hold where you are.