Glascock acknowledges that neutron activation analysis alone is not going to convince everyone, adding that the process of determining a chemical fingerprint isn't foolproof. "When I analyze pottery from say, San Lorenzo and compare that to Monte Albán [a major archaeological site near Oaxaca, Mexico], the chances of error can be as much as several percentage points on individual samples. It's not as precise because the pottery material has more variables."

Scientists overcome this potential pitfall by employing large numbers of samples and using proven statistical models to interpret the data. "The way that we have worked with our data sets allows us to actually calculate a number, a physical probability, of this sample being a member of another [source] group -- we are using multi-layered statistical techniques that allow us to do that," Glascock says. "So it is possible to state that 'I am 99 percent sure that this sample belongs to this group,' or 'I am 50 percent sure.'"

With the Olmec artifacts, he adds, the results were relatively unambiguous. The first paragraph of Blomster, Neff and Glascock's Science article makes his point with admirable clarity: "Using elemental analysis, we determined the regional clay sources of 725 archaeological ceramic samples from across Mesoamerica. Exported Olmec-style ceramics originated from the San Lorenzo region of the Gulf Coast, supporting Olmec priority in the creation and spread of the first unified style and iconographic system in Mesoamerica."

In an editorial that accompanied the group's Science article, archaeologist Richard Diehl, an author and professor at the University of Alabama-Tuscaloosa, elaborated on the implications of the finding. Diehl, who worked as a graduate student assistant with Coe on the excavation of San Lorenzo in the 1960s, served on the MU anthropology faculty from 1968 to 1986.

The analysis "provides powerful support for the mother culture school," he wrote. "The study by Blomster et al. reveals complex trading patterns of social integration that probably varied from place to place and through time. It documents the movement of Olmec pottery, along with the ideology reflected in its decoration, from San Lorenzo to foreign communities, and the integration of Olmec icons, beliefs, and practices into local indigenous systems. Later imitation of this pottery in local clays reflects the solidification of this transfer of ideas.

Coe says the data from MU's reactor should settle once and for all the mother-sister imbroglio: "There is no more controversy. Just like radiocarbon dating and really good stratigraphy was necessary to settle that business about priority of Olmec over Maya, so the issue of the diffusion of Olmec culture to other areas in Mesoamerica has been settled by the research at Missouri. I mean, that's the final arbiter -- what the chemistry says about this."

Glascock, on the other hand, isn't so sure. He cites, with a sigh, Grove as an example of the unreconstructed: "They think we didn't analyze the right samples; that's what Grove said. Well, how many do you want to analyze? In fact, he doesn't know that while the Science article talks about 725 artifacts analyzed, we've actually analyzed around 2,000. So there is even more data than was expressed in the article -- the 725 were just those that were adequate to tell the story. There were many more, and they all seemed to indicate the same thing."

Exasperating? Hardly, says Glascock, it's all part of the scientific process. Still, the 25-year archaeometry lab veteran can't help but throw down a challenge to Grove and his allies. "My invitation to them, if they would listen to me, is this: 'If you've got samples that you would like to analyze, let's analyze them and see if your theories are correct.' "

Published by the Office of Research.

©2006 Curators of the University of Missouri. Click here to contact the editor.