The purpose of Mesoamerican potbelly statues have been the subject of debate among anthropologists for decades: Are they depictions of the ruling elite? A way to honor dead ancestors? Or perhaps portrayals of women giving birth?

As the various theories wound their way through academic circles, the surprising discovery four decades ago that many of the statues, found in Guatemala, are magnetized in certain spots added a new dimension to those discussions.

And a Harvard study suggests that where those areas show up is no accident.

Led by Assistant Professor of Earth and Planetary Sciences Roger Fu, a team of researchers has shown that artisans carved the figures so that the magnetic areas fell at the navel or right temple — suggesting not only that Mesoamerican people were familiar with the concept of magnetism but also that they had some way of detecting the magnetized spots. The study is described in an April 12 paper published in the Journal of Archaeological Science.