Assuming 5000 Unique Raw Materials

Raw Material Richness in Tool Kit Two different patterns are visible when investigating raw material richness. First, when a forager engages in random or wiggle walk, a more clustered environment leads to lower average raw material richness in the toolkit (Fig.

Fig. 4.4 Average richness of toolkit. Y values are shown as log values. Each curve is based on the average of 100 simulation runs

In the other pattern, the forager engages in a seeking walk and seeks the closest raw material sources when the tool kit is empty. In this case, the increased clus­tering of raw material sources leads to increased raw material richness (Fig.

Distance Materials Travel Until Discarded In terms of the distances that raw materials travel until discarded, two patterns can be observed (Fig. 4.5). In the first pattern, when a forager engages in random or wiggle walk, increased clustering leads to decreased travel distance (Fig. 4.5). However, not both of these relation­ships are statistically significant. The random walk data has a strong but non-significant relationship with the p_r values (Spearman’s rs = 0.7; p = 0.2), while the wiggle walk data has very strong and significant relationship with the p_r values (Spearman’s rs = 1; p = 0.02). Because raw material richness increases with increased random distribution of sources as shown above, the probability that any one raw material is consumed decreases. This decreased probability means that there is increased chance that any one raw material will stay in the tool kit for a longer time, which results in raw materials being carried for longer distances before being consumed.

Fig. 4.5 Average distance materials are travelling from the source. Each curve is based on the average of 100 simulation runs

On the other hand, when the forager engages in a seeking walk, increased clustering leads to increased travel distance (Fig. 4.5). However, this relationship is not significant although there is a strong negative correlation (Spearman’s rs = -0.7; p = 0.2). As noted above, tool kit richness controls how long a raw material travels before being consumed.

Time Steps Without Material in Tool Kit When investigating how much time the forager spends without material in the tool kit one clear pattern can be observed: clustering leads to increased time without materials in the tool kit. Across all three simulated walk behaviors, the analysis shows that when resources are more clus­tered than simulated in the original neural model, we can expect that foragers run out of materials for longer periods of time (Fig. 4.6). All three walk behaviors have significant and strongly negative relationships with the p_r values (Table 4.1). Table 4.2 shows the estimated time steps without raw materials. If engaging in random or wiggle walk, the forager will on average spend about 55 time steps without materials when the raw materials are randomly placed as simulated in the neutral model. However, as the clustering of the raw material sources increases to mimic a realistic landscape, one can observe that time spent without materials increases 10-30 times. This is because increased clustering leads to more spaces between sources leading to an increased probability that a forager will use up all the raw materials in the tool kit before encountering a new source. Hence, the original neutral model might not be an appropriate model for landscapes with raw material sources clustered like is often typical of most environments. It is unrealistic to expect that foragers go extended periods of time without raw materials in their tool kit to create and repair tools.

Although ethnoarchaeological work and ethnographic description offer some evidence that stone procurement was a daily exercise for some groups (Hayden and Nelson 1981; MacCalman and Grobelaar 1965; Miller 1979; Sillitoe and Hardy 2003; Stout 2002) it has to be noted that this behavior cannot be considered a universal behavior, and that caches of stone to provision daily use can also be maintained at a central location where the foragers operate (Parry and Kelly 1987).

Not surprisingly, when the forager is engaging in seeking walk behavior, the time spent without materials is decreased drastically compared to random and wiggle walk simulations (Fig. 4.6). However, even in seeking walk simulations an

Fig. 4.6 Average number of time steps a tool kit is empty. Each curve is based on the average of 100 simulation runs

Table 4.1 Spearman’s rs test results

Table 4.2 Time steps spent without material in tool kit

increased clustering of the raw material sources leads to more time without any raw materials in the toolkit. This is because there is an increased probability that a forager can find itself further from a cluster or any single source because of the increased space between any sources. This means that the forager has to travel further to find the nearest material, which leads to increased time without material in the tool kit.

4.3.2