Object relocation task: an exact test of significance with credit for partial knowledge

The object relocation paradigm is used to assess spatial memory in cognitive, developmental and clinical neuropsychological contexts. A number of different objects are displayed for a period of time in a particular spatial environment, such as a room, a desktop, or a computer screen. The objects are then cleared away, and the subject is asked to replace them in their former locations. In this paper, a simple measure of individual performance on the task that gives equal credit for near misses and correct responses is presented, and an exact small-sample test of significance for the measure is developed using rook methodology. A weighted-credit test of spatial performance is also presented. Computational examples are provided to illustrate the methods.