McGovern's team based their conclusion on finding traces of the chemical theobromine, a chemical found only in cacao plants, in pottery vessels used to hold liquids.
It is not clear what the drink looked like or how it tasted, McGovern said. But it would have had a sweet chocolate taste, he said. "Later, when the drink was being made from the bean, other things such as chilies, honey, and flowers and spices were added," he said.
Chocolate drinks made from the cacao bean were later used by the Mayans and Aztecs, McGovern noted.
Henderson said the findings pointed to the haphazard way customs developed and changed over time.
He argued that it was significant that the first use of chocolate was sourced and fermented from the plant's pulp. If this is true, then the way the Aztecs and others used chocolate, as well as the modern chocolate industry, "becomes an accident. An unintended consequence of early beer brewing," he noted.
"It makes a nice example that important developments are not self-consciously done by intended result," Henderson added.
McGovern said his team had also found the oldest known alcoholic beverage in the world. It came from China and dates from 7000 B.C., he said. The drink was made from rice, honey and hawthorn, or wild grape.
It appears that "humans are interested in finding anything that will ferment," McGovern said.
For more on the history of chocolate, visit The Field Museum.
SOURCES: Patrick McGovern, Ph.D., senior research scientist, associate professor, anthropology, Museum Applied Science Center for Archaeology, University of Pennsylvania Museum, Philadelphia; John S. Henderson, Ph.D., professor, anthropology, Cornell University, Ithaca, N.Y.; Michael
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