WebExp Demo Paradigm:   Mental Rotation


The experiment presents transformations of an image, either a recognisable symbol such as a letter, or a more abstract object (often three-dimensional). The task is to identify whether the object has merely been rotated, or if the transformation also involves reflection.

The results of the experiment show a linear correlation between the amount of rotation and the time taken to decide if the rotated image is identical to the original. This may be interpreted as indicating that a mental model of the object is constructed by the user, and rotated in the mind - and thus that thought involves visual/spatial manipulation processes, contrary to the Behaviourist idea that thought processes depend upon language.


  • Wexler, Mark, Kosslyn, Stephen M., and Berthoz, Alain. 1998. Motor processes in mental rotation. Cognition 68: 77-94.
  • Kosslyn, Stephen M. 1994. Image and brain. Cambridge, MA: MIT Press.

The Experiment

An implementation of the Mental Rotation experiment using the rotated alphabetic characters employed by Cooper & Shepard (1973). There are 12 stimuli comprising an image of the letter R, its mirror image, and each image rotated through 60 degree increments.

There are 2 sections to the experiment - the first shows transformations of the letter R, and the second transformations of an abstract symbol. The 12 images in each section are shown in a randomised order.

WebExp Demonstrations 2008 The University of Edinburgh