Shepard-Metzler Mental Rotation

In 1971, Roger Shepard and Jacqueline Metzler ran an experiment on mental rotation. They showed people a 3D object and the same object after a rotation, and perhaps a reflection. Response time for judging whether the two shapes are the same or mirror images increases linearly with the angle between them, as if the mind is literally turning one object to match the other. People typically rotate at about 60 degrees/second, and rotation rate weakly (r ≈ .25) correlates with IQ.

Judge whether these shapes are the same shape or mirror images. Press F for same, J for mirror. On mobile, use the buttons.

Stimuli from Ganis, G. & Kievit, R. (2015). A New Set of Three-Dimensional Shapes for Investigating Mental Rotation Processes. Journal of Open Psychology Data, 3(1). CC BY 4.0.