Final Thoughts

Graphs are analytical tools and communication tools, and they summarize visually what has been learned. Granting that a major purpose of archaeology is to document and explain culture change, it is odd that the hows and whys of graphing culture change have received minimal attention in the archaeology literature. Spindle graphs will likely continue to be the most frequently used graph type for diagraming change, but continued development of computer software may result in new graph types and styles. Recent modifications to spindle graphs include scaling bar thickness to temporal duration of the represented assemblage. Classic data on temporal change in kaolin pipe stem hole diameters can be graphed using a regression line, a bar graph, and a spindle graph; the different graphs highlight that how phenomena are classified, how data are graphed, and one’s theory of change are mutually influential. Deciding which graph type to use in any particular situation will depend on what the researcher hopes to illustrate, along with the goal to produce a readily deciphered graph. The majority of archaeological graphs that appeared in the twentieth century depict variational evolution. Once developed in the late 1940s, spindle graphs quickly became the graph type preferred by North American archaeologists. There is weak circumstantial evidence archaeologists may have borrowed the idea of spindle graphs from paleontology, but it seems more likely the idea was stumbled upon by early archaeologists who perceived unimodal pulses in artifact frequencies over time and developed general models of those pulses.