Mental Rotation Experiment


Are the blue and red objects mirror images of each other, or are they the same shape? Press the Mirror button if you think they are mirror reflections (that may have been rotated) or the same shape (again, which may have been rotated). Try a few times, for practice, then when you are ready, Press the reset button. Try to decide as quickly and as accurately as you can. Your reaction times for the correct responses are being recorded. When you have done this about 70 times (it only takes a minute or two), press the "Statistics" button to see your performance.

Fr Chris' Java source code.

Reflection Questions

  1. How much can you improve with practice?
  2. Does everyone perform the same?
  3. There are two factors shown in the Statistics Page:
    1. The intercept or where the line starts
    2. The slope (or steepness) of the line, as the angle increases
  4. What does a high intercept reflect?
  5. What does a flat slope reflect?
  6. Do you think that the greater the angle, the greater the reaction time? Why or Why not?


Psychologists discovered that people can simulate the rotation of an object in their head in a way that is similar to physically rotating it. Rather than do a "point-to point" comparison to see if these objects are mirror images, people tend to rotate the object in their head in such a way that it takes longer to respond to the task if the objects are rotated a lot. To prove the point, this experiment demonstrates that the more rotation required, the more time it takes.