Increasing settlement system stability

In addition to a reduced population growth rate, the Middle Formative settlement system also demonstrated greater stability compared to that of the Early Formative. While the occupation continuity index remained stable at a relatively high 64 (compared to 63 for Middle Chiripa), the site founding index decreased greatly, from 78 to 55. On the whole, then, throughout the Middle Formative Period, the inhabitants of the Taraco Peninsula continued to live in the same villages as previously, with a very low abandonment rate. It was, however, becoming increasingly difficult to found new villages, as reflected by the drastically reduced site founding index. Indeed, there is only one likely case of village fissioning in the Middle Formative. Compare this with the two very clear cases of villages fissioning in the Middle Chiripa phase, which lasted for only approximately 200 years. If we calculate a rate of village fissioning in terms of events per century, we would say that this rate fell dramatically in the Middle Formative, from 1.0/century (Middle Chiripa), to 0.18/century (Late Chiripa).

In fact, however, this would be to downplay the radical nature of the change. I suggested earlier that in the Middle Chiripa phase there existed a settlement size threshold beyond which fissioning became extremely likely. This threshold was empirically located, in terms of my population index, at approximately 150, quite a small village.

The last instance of Formative Period village fissioning on the Taraco Peninsula seems to have taken place at the beginning of the Late Chiripa phase. From that point on, the existing villages continued to grow throughout the Middle Formative without fissioning or relocating. This fact would seem to indicate that by early in the Middle Formative mechanisms - institutions, practices - were developing to deal with the stresses and pressures that arise in large, permanent villages. This was in fact a significant evolutionary milestone in its own right.

Together, the decrease in the population growth rate and the increase in settlement system stability can be taken as an indication that the landscape of the Taraco Peninsula was beginning to fill up in the Middle Formative. That is to say that the territory of the peninsula was by this time claimed in its totality, and being utilized in some manner by its inhabitants. The difficulty of village fissioning and relocation increased substantially in the Middle Formative, tethering the local population to its villages.

Figure 6.9: Middle Formative site size distribution