ABSTRACT
This chapter addresses what is the structure and capacity of spatial memory and how can it be modified, what kinds of changes in radial-arm maze performance would result from alterations in the structure or the capacity of spatial memory. It shows that improvement in choice performance results from the hierarchical clustering of food sites in spatial memory made possible by the use of multiple food types placed in fixed spatial locations and the rats' ordered preference among the food types. The primary difference between the problem-solving ability of the rats in the Chunk group and the control groups is therefore properly described as qualitative, having been derived from the by-category organization of data in spatial memory and the reallocation of priorities given to response versus memory strategies. Spatial memory performance was further assessed by calculating the mean number of choices executed before the first working memory error occurred in each trial.
