Scientists Discover That the Incest Taboo Has Been Around for a Long Time

New findings show that as far back as 34,000 years ago, there was already an incest taboo among early humans. Research suggests that these humans deliberately sought to mate outside of their families.

Resconstructions of the faces of one of the adults, as well as the two younger individuals [Photo by the Institute of Archaeology]

Because of technological advancements, we know now how inbreeding affects us as well as other animals genetically. However, early humans did not have such technologies. Even so, a new study tells us that these early humans likely deliberately avoided inbreeding by forming laws and social norms compelling them to find mates they're not closely related to. It's also possible that the avoidance of inbreeding is what allowed anatomically modern humans to prosper, while other now-extinct hominins like Neanderthals seemed to have not had qualms about inbreeding.

The remains of four prehistoric individuals in Sunghir, Russia suggest that they lived in a society with surprisingly complex rules and norms on mating as well as the recognition of family ties. Researchers believe that this allowed the people in these societies to avoid inbreeding.

Benefits of the Incest Taboo

An illustration of one of the adults

Sunghir is an Upper Paleolithic site in Russia, where some of the earliest traces of Homo sapiens can be found. It was here that four early humans, all male and all anatomically modern, were buried. The complete remains are of one adult and two younger individuals, while the incomplete remains, which were symbolically modified, were of an adult as well. The children's grave also contains a femur, stained with red ochre, which belonged to an individual that was probably the children's great-great-grandfather. All of the individuals seem to have lived in the same time period and were buried together.

The younger individuals were laid head to head in their grave.

Surprisingly, in spite of the fact that the individuals were buried together, genetic testing revealed that they were not in fact closely related. They were possibly second cousins, but no closer than that. This was unexpected, as burials like this are usually expected to contain the remains of closely-related individuals.

The graves also contained jewelry and other objects that indicate that the society the individuals belonged to must have had rules and rituals pertaining to the exchange of mates between distinct groups. According to the researchers, this prehistoric society may have used jewelry to distinguish between different groups. These distinctions may have helped individuals figure out who to avoid mating with due to the incest taboo.

Avoiding Inbreeding

All the graves included a considerable amount of jewelry as well as other artifacts.

“What this means is that even people in the Upper Paleolithic, who were living in tiny groups, understood the importance of avoiding inbreeding,” said Dr. Eske Willerslev, one of the researchers.

It's possible that the early humans in Sunghir lived in small bands of about 25 people, with these bands being part of a larger community with a population of about 200. This community may have had rules on who each individual can and cannot mate with.

This makes early humans different from Neanderthals, who may not have avoided inbreeding. Genetic testing on the 50,000-year-old remains of a Neanderthal in the Altai Mountains, for example, showed that the species likely didn't avoid mating with close relatives. It's possible that the incest taboo may have helped our species thrive and survive.