This chapter discusses one of the procedures that have been developed to measure one aspect of the social environment: the intensity of interaction between communities and outlines the way this variable has been measured. The geographical literature dealing with the prediction of interaction between communities is extensive. Archeologists have attempted to measure the intensity of interaction among rooms within a prehistoric community and among communities by quantifying the degree of similarity of stylistic attributes—pottery designs in particular—on artifacts from the units. A. Shepard has discussed a number of variables, such as clay source, insufficient oxygen, length of firing, and firing temperature, that can cause variation in the color of pottery. A potter only can control the variables of the firing process within a certain range, so that differential frequencies of colour categories may be only a result of random variation.