date brackets an interval of 80 radiocarbon years when the plant might have died.
When radiocarbon analysis was initially introduced, analyses of samples used to measure the beginnings and endings of phases and periods were translated by a simple process of subtraction, counting backward from 1950 CE. Later, researchers realized this simple procedure was based on an incorrect assumption: that the concentration of different forms of carbon in the atmosphere had not changed over time. Specialists in chronometric dating have produced highly detailed graphs showing fluctuations in concentrations and calculated the divergence between the simple radiocarbon age and the real calendrical age. Computer programs allow archaeologists to calibrate radiocarbon years and estimate real calendar years of the interval when the plant or animal producing a carbon sample most likely died.
The effects of calibration can be substantial. The aforementioned sample from Puerto Escondido corresponds to 1690–1510 cal. (calibrated) BCE. If we simply had subtracted the radiocarbon years from 1950 CE, the same sample could have been mistakenly treated as the date 1370 BCE, plus or minus 40 years, or an interval from 1410 to 1330 bce. A plant that actually died sometime between 1690 and 1510 BCE might have been thought to have lived and died centuries later. All the historical events and all the people whose lives that single carbon sample dates could have been falsely thought to have taken place much more recently than they actually did.
Even when a shift in dates seems relatively minor, calibrating radiocarbon dates corrects potential misunderstanding of the length of an interval of time. Sample Beta-129125 from Puerto Escondido was dated 1530 +/− 40 BP in radiocarbon years. If we just counted backward from CE 1950, this would mean the plant producing this carbon died between CE 380 and 460. The calibrated date range was actually cal. 430–625 CE. Not only does calibrating change the date of the depositional event that yielded this carbon sample from Early Classic to Late Classic, but it also greatly increases the span of time within which the event most likely occurred, from 80 to 195 years.
The effects of calibrating samples do not vary in a single predictable way. Puerto Escondido sample Beta-129126, at 2730 +/− 40 BP in radiocarbon years, would correspond to the span from 820 to 740 BCE if we just counted backward from 1950 CE. The calibrated date span of cal. 940–810 BCE shifts the interval earlier (instead of later as in the previous example) and changes the interval of highest probability to 130 calendar years (from 80 radiocarbon years). These effects matter when archaeologists are interested in understanding the rate of change and timing of actions within a society over individual lives and connected generations, the kind of timing seen in indigenous calendar notations, critical to contemporary archaeological interpretation.
Mesoamerica as a Culture Area: From Traits to Practices
Mesoamerica was originally defined as a culture area based on a checklist of traits ranging from basic religious concepts to minor details of costume (Kirchhoff 1968 [1943]). The compilation of a trait list is now rejected as too crude a way to group societies or archaeological sites because it treats all similarities as being of equal importance and provides no way to explain how or why such connections came into being. Archaeologists still find the concept of Mesoamerica useful because it allows them to connect cultures which, through extensive interaction, developed a common set of values and practices that continued to develop over a long period of time, from at least 3500 years before European contact.
We can thus reimagine the Mesoamerican trait list as indicating shared practices in a number of distinct social domains. The most important of these domains are (1) the economy, (2) philosophical and scientific understanding of how the world works, and (3) social differentiation (Table 1.2). What we see today as a continuous Mesoamerican tradition is the result of generations of practices by people working within the bounds of what they understood to be both possible and desirable. In this sense, Mesoamerica had a beginning point, a period when the practices and beliefs we recognize as Mesoamerican emerged. Gordon R. Willey (1966: 78) long ago identified Mesoamerica’s origins with the time period beginning around 2000 BCE when village life dependent on corn agriculture took form, in settlements where social stratification first becomes evident. Many of the practices identified as typical of Mesoamerican culture are expressions of social differences that first took emerged in early villages. This volume begins coverage of Mesoamerica at this moment of early village life and emergent social stratification (Chapters 2 and 3).
Table 1.2 Archaeologically identifiable defining traits of Mesoamerica, organized according to social and cultural practices
| Arena of practice | Traits from original definition of Mesoamerica |
|---|---|
| Subsistence production | Agriculture based on corn, beans, and squash, dependent on human labor using digging stick |
| Agricultural intensification including raised fields (chinampas) | |
| Plants raised for specialized uses: cacao, amaranth, maguey | |
| Corn processed by soaking with lime and grinding on metates | |
| Long-distance exchange | Valuables such as obsidian, cacao, and jade |
| Cosmology and ritual | Numbers 4, 5, 7, 9, 13, and 20 significant |
| shared calendars: solar year of 18 months of 20 days plus a set of 5 final days; 260-day ritual cycle of 13 day names combined with 20 numbers | |
| Use of writing and positional mathematics to record astronomy and calendar, in paper and deer skin books (codices) and more permanent media | |
| Ritual warfare, special warrior costumes, and human sacrifice | |
| Specialized architecture for ritual: ball courts, temples, observatories, including use of stucco | |
| Social stratification | Status expressed in costumes, including gender specific forms of dress, role-specific headdresses, warrior outfits, and ornaments such as lip plugs, pyrite mirrors, and polished obsidian mirrors and earplugs |
In any social world, intentional and unreflexive actions carried out by people, acting along with other humans and in concert with nonhumans (animals, things, and forces beyond the human, like rainfall), produce, reproduce, and transform structures. People reproduce and transform social structures through their choices among possible ways to act that they see open to them. In the process of exercising their perceived ability to act (or agency), reproducing and transforming structure, people create and add to individual and group histories, shaping the constraints and possibilities of agents in succeeding generations. People make their choices of action, and understand their implications, based on their philosophies of being (ontologies), their understandings of the nature of the origins of things (cosmologies), and their broader view of relations among all beings. In many ways, the most distinctive aspects of Mesoamerica belong to this philosophical domain.
Mesoamerican Philosophies of Being and Becoming
Mesoamerican peoples were agriculturalists, living in socially differentiated communities, understanding themselves to exist in specific kinds of relations to other humans and nonhuman entities and forces.
