Food crops such as wheat and maize become standardized in this age.

The domestication of maize is of particular interest to researchers—archaeologists, geneticists, ethnobotanists, geographers, etc.

The process is thought by some to have started twelve thousand to seven thousand five hundred years ago.

Research from the 1950s to 1970s originally focused on the hypothesis that maize domestication occurred in the highlands between Oaxaca and Jalisco, because the oldest archaeological remains of maize known at the time were found there.

Genetic studies led by John Doebley identified Zea mays ssp. parviglumis, native to the Balsas River valley and known as Balsas teosinte, as being the crop wild relative teosinte genetically most similar to modern maize.

However, archaeobotanical studies published in 2009 now point to the lowlands of the Balsas River valley, where stone milling tools with maize residue have been found in an eighty-seven hundred-year-old layer of deposits.