What was this used for? – Part 1

By Matthew Davidson

Any archaeologist who has worked with the public has heard this question more times than they can remember.  This blog post responds to the question using stone tools as an example.  So, how do archaeologists know how stone tools were used by Native Americans? 

Until about the 1970s, the function or use of stone tools was thought to be based on their shape.  In the early 20^th century, archaeologists thought that if a stone tool was shaped like a “knife” it must have functioned like the knife we use today.  By the mid-1900s archaeologists started comparing the shapes of stone tools they found at archaeological sites to examples used by people living today, and from historic accounts of how stone tools were used.  This allowed them to directly observe how stone tools are made and used.  For the purpose of this blog, we will call this the comparative method.

A person in Ethiopia making a stone scraping tool circa 1975 [top], and the scraper after being inserted into a wooden handle [bottom] (from Gallagher 1977: Figures 3, 10).

The thinking behind the comparative method was that if a stone tool was observed to be used for a specific activity, all similarly-shaped stone tools could have been used the same way.  Since we cannot go back in time and observe how every stone tool was used in the past, this method is a quick and easy way to interpret tool use or function.  Over time, the comparative method of determining stone tool function resulted in certain “types” being established in the archaeological literature.  Examples include projectile points, knives, hoes, adzes and scrapers.  In fact, if you look at any old archaeology report or book, you will see these types.  The example below is from an early 1970s archaeological study in eastern Kentucky (Pike County).

Example of how archaeologists used to describe stone (and other) tools (from Dunnell et al. 1971).

A new method of identifying stone tool function or use was established during the 1970s and 1980s.  This involved a three step process: 1) making replica stone tools, 2) using them, and 3) then studying the used replicas.  The archaeologist starts by making replicas of a certain type of stone tool – let’s say, for example, arrow heads (also known as tips or projectile points).  Then, the archaeologist would attach the replica arrow tips to wood projectile shafts and shoot them at a variety of targets.  Finally, the used arrow tips would then be examined under a microscope to see what kind of damage and wear the arrows received from hitting different targets. 

Examples of arrow tips [top] and spear tips [bottom] attached to projectile shafts (from Odell and Cowan 1986: Figure 1).

When examined under a microscope, the archaeologist can see what happened to the surface of the arrow tips when they hit different materials, such as the animal’s hide, muscle, bone and antler.  Sometimes they are chipped or broken (see next figure).  Other times, they may only have very fine wear that can only be seen with a microscope.  The experimental method has now been used for half a century and archaeologists have a well-established record of how different activities (scraping, cutting, piercing) and materials (hide, bone, antler, stone, wood) can damage and wear down a stone tool.  Archaeologists studying stone tool use tend to separate damage and wear.  Damage describes when a tool is chipped or broken as a result of hitting another object at a high speed, a harder material, or a material under high pressure or heat for long periods of time.  Wear describes scratches or abrasions, rounding and polishes that develop on the edges and surfaces of a tool, typically through gradual or repeated use.  Example images of damage and wear are shown below.

Examples of damage from experimental use of replica arrow tips (b,g) and spear tips (a,c-f).  The types tips used in this experiment are common in Kentucky (a. Snyders, b. Matanzas-like, c. Kirk-like, d. St. Charles, e. Cahokia, f. Clovis Unfluted, g. Madison; from Odell and Cowan 1986: Figure 2).

Examples of wear observed on a Clovis spear tip at 200x magnification. Top: flattening and polish from butchering. Center: striations (lines) left from where the tool was attached to the projectile shaft. Bottom: a combination of polish from butchering and striations from an impacting a target (from Kay 1996: Figures 8-11).

So, how do the comparative and experimental methods for documenting stone tool use compare?  Well, the experimental method is far more accurate and can pinpoint exactly what a tool was used for.  However, it is also true the certain shapes of tools are pretty consistently used as arrow and spear tips, scrapers, etc.  However, we now know that tools were often recycled after they were worn out or broken.  We also know that many tools were used for multiple different activities – like multi-tools.  To truly understand what stone tools were used for, we have to examine them on a case-by-case basis.  Stone tools all have their own history, and now archaeology has the methods to recount that history. 

References

Dunnell, Robert, Hanson, Lee, and Donald Hardesty

1971  The Woodside Component of the Slone Site, Pike County, Kentucky. Southeastern Archaeological Conference, Bulletin No. 14.

Gallagher, James

1977  Contemporary Stone Tools in Ethiopia: Implications for Archaeology.  Journal of Field Archaeology 4(4):407-414.

Kay, Marvin

1996  Microwear Analysis of Some Clovis and Experimental Chipped Stone Tools.  In Stone Tools: Theoretical Insights into Human Prehistory, edited by G. Odell, pp.315-344. Plenum Press, New York.

Odell, George

2004  Lithic Analysis.  Kluwer Academic / Plenum Publishers.

Odell, George, and Frank Cowan

1986 Experiments with Spears and Arrows on Animal Targets.Journal of Field Archaeology13(2):195-212.