The Mother-Sister Controversy
The mother-sister controversy in Mesoamerican archaeology is a debate over the relative importance of the Olmec civilization over the rest of central America. Archaeologists who work in Mesoamerica are to a large extent split into two camps. The 'mother faction' believes that the Olmec were earliest and held much power and influence over Mesoamerica during the Early Formative period (ca. 1200-500 BC). Conversely, the 'sister faction' believes that the formative cultures of Mesoamerica were more or less equal in power and sophistication at the same time.
In spring of 2006, Mark Aldenderfer, editor of Latin American Antiquity, invited both factions to provide commentary in the pages of his journal, to attempt to put all the supporting data in one place and allow the rest of us to make up our minds. This was a brave and honorable effort, but the result was confusion, at least by my lights. It seems to me that the mother-sister debate isn't really about that at all.
Factions and Realities
For one thing, both factions believe pretty much the same thing--that the Olmec were first in some things in Mesoamerica and had some two-way trade with the other burgeoning societies (such as the forerunners of the Toltec and Zapotec cultures).
To argue that there was no trade or other connection would be foolish--there is clear evidence of similarities within the cultures, in the form of stylistic similarities in artifacts and the spread of domesticates and some artifact types like ceramics. To argue that the Olmec were not the first to, say, build public monuments, would also be foolish; since San Lorenzo's Early Formative earthen mounds are still the most massive monumental structures known in central America at that date. (However, San Lorenzo is not the earliest in the entire Americas--that would be the Caral-Supe civilization, some 1400 years earlier.) What Latin American Archaeology's spring 2006 issue showed is that the two factions have set up paper tigers, and the fact that they agree on the essentials while disagreeing on some of the details is not noted by either side.
The Mother-Sister Controversy and the Cascajal Block
What the Cascajal block does, if the dating holds up, is suggest that the Olmec did have a representational writing system in place by the Middle Formative period. Dating of the object has not been completed; no mention of the feasibility of dating of the patina occurs in the story as published. Beyond that, two questions remain: one is, why are there no other extant examples of this writing style--Rodriguez et al suggest that the writing might have been used on wooden artifacts that have since all but disappeared. The second question is, why is there no connection between these early writing attempts and the later writing styles of central America. In this respect, Rodriguez and colleagues believe the Cascajal block may be an isolated example of writing, or a widespread language that disappeared by ca 500 BC.
Has the mother-sister controversy been put to rest? My guess is, no, that the 'sister faction' will soon address the problems with the dating of the Cascajal block. But isn't it interesting?