In adapting the model, Kestemont and his co-authors treated literary works as species and manuscript copies as sightings of a species.
"It's even been used to estimate the number of stars in a galaxy or the number of bugs in a piece of software that haven't been discovered yet," said Kestemont. "The real question is 'in which conditions wouldn't we be able to apply it?'" As long as you can distinguish something akin to "species," the model works very well. "In fact, this method isn't even specific to ecology." Chao1 is so general that it's been used in lots of other fields, with "species" standing in for classes of stone tools (archaeology) types of die for ancient coins (numismatics) different causes for a given disease (epidemiology) genes or alleles (genetics) and distinct vocabulary words (linguistics), to name a few. "Then you have a lower bound on the estimates of the number of species you didn't observe," said Kestemont.īut can an ecological model really be applied so readily to such a markedly different scholarly domain? "Intuitively, it's a weird thing to say that a literary work behaves like a species," Kestemont acknowledged. Those numbers can then be used to calculate F0-the number of species that have been observed exactly zero times in an area. If you only spotted a species once, for example, it would be designated "F1." If you've spotted a species twice, it would be F2.
The Chao1 formula will look at those species that don't appear often in the abundance data. The issue is that certain hard-to-observe species will be missed in that count. (Snow leopards, for instance, are notoriously difficult to spot.)
First, scientists collect "abundance data," counting all the animal species they can observe.
The Chao1 model is meant to give users an accurate estimate of how many species inhabit an area, said co-author Mike Kestemont of the University of Antwerp. However, losses were significantly lower in Icelandic and Irish literature, suggesting that island ecosystems might help preserve culture. In fact, the team's results were very similar to the estimates made by scholars using other data, such as references to lost works that appear in surviving manuscripts. The team looked at medieval works in Dutch, English, French, German, Icelandic, and Irish and concluded that only about 9 percent of medieval manuscripts survived. The authors also presented their findings last week at a virtual meeting of the American Association for the Advancement of Science (AAA). According to a new paper published in the journal Science, an international team of researchers has adapted an ecological "unseen species" model to estimate how many medieval European stories in the chivalric romance or heroic tradition survived and how much has been lost. The field of ecology might be able to help. Teasing out how much of a cultural domain may have been lost is a considerable challenge. Those who study human culture must grapple with what amounts to an incomplete data set, since researchers are limited to poring over the books, manuscripts, paintings, sculptures, and other artifacts that have survived to learn about a given period. We call this predicament "survivorship bias," and it can lead to underestimations of just how diverse a society might have been in terms of the cultural materials produced. An ecological model has been applied to estimate the number of lost medieval manuscripts in Europe.