ABSTRACT
Almost 50 years ago, George Miller’s (1956) survey of the literature on human information-processing capacity resulted in his being persecuted by an integer, specifically the number 7, which at that time had magical properties (see Miller, 1956). Today, our consideration of the literature on human spatial memory has led to similar vexation. We too have been visited repeatedly by an integer, in our case the number 2. Miller’s troublesome number came in a variety of disguises, but none of these was so opaque as to make the intrepid integer unrecognizable. Similarly, we see significant diversity in the context of spatial cognition, but dual systems or processes are a consistent theme. Repeatedly, we have encountered accounts of two means of coding spatial relations, one related to precision and one to proximity. Rather than ignore this intriguing phenomenon, we elected to address this dauntless digit directly in this chapter.
