Rotational Error

Some of the most interesting regularities found in the reorientation task pertain to a particular error in reorientation.  In an arena with no unique feature cues (no unique wall color, no unique pattern at each corner), geometric cues are the only information available for reorienting.  However, geometric cues cannot uniquely specify a goal location in a rectangular arena.  This is because the geometric cues at the goal location (e.g. 90° angle, shorter wall to the left and longer wall to the right) are identical to the geometric cues present at the diagonally opposite corner (often called the rotational location).  Under these conditions, the agent will produce rotational error (Cheng, 1986, Cheng & Newcombe, 2005).  When rotational error occurs, the trained agent goes to the goal location at above chance levels; however, the animal goes to the rotational location equally often.  Rotational error is usually taken as evidence that the agent is relying upon the geometric properties of the environment. Thus if rotational error is evident in conditions where geometric information is not required, then this suggests the possibility of a geometric module.

References:

1. Cheng, K. (1986). A purely geometric module in the rat's spatial representation. Cognition, 23, 149-178.
2. Cheng, K., & Newcombe, N. S. (2005). Is there a geometric module for spatial orientation? Squaring theory and evidence. Psychonomic Bulletin & Review, 12(1), 1-23.

(Added September 2010)