There are a lot of theories regarding monogamy and how it became possible, given the supposedly polygamous nature of humans. Some of these theories imply that people became monogamous to prevent other men from killing their children, others refer to the fact that men wanted to defend their resources and make sure the babies born by the women they mated with were theirs.
However, an anthropologist working at the University of Utah, Kristen Hawkes, comes to contradict both these theories and give a brand new one – the nuclear family exists because of our grandmothers. The “Grandmother Hypothesis” says that grandmothers played a very important part in the evolution of romantic relationships between men and women and had a major contribution to our longer lifespan.
“It looks like grandmothering was crucial to the development of pair bonds in humans,” said Hawkes. She first introduced the theory in 1998, when she only referred to grandmothers’ key roles in longer lifespan.
After 17 years, Hawkes gave them even more credit, saying that grandmothers were the ones who helped increase the lifespan of people because they took care of children who were no longer breastfed. Therefore, these children had higher chances to survive and become adults. After some time, the longevity genes became more and more prominent in humans and the population grew faster.
Moreover, by taking care of children, women could have more babies and the men were kept busy and stopped looking for other female partners to mate with. Afterwards, they needed to stay and protect their offspring and mates from other men, which made the relationship between them and their partners a more stable and long-lasting one.
Because it was easier to stay at home and protect the mother of their babies than go out and fight for new partners, most men felt comfortable with the situation. At the same time, there were fewer fertile women than fertile men, which made it even more difficult for males to find someone to mate with for procreation. Thus, they just chose to protect their mates, according to Kristen Hawkes.
“Mate-guarding and pair bonds are not necessarily the same, but they have in common the trade-off between paying attention to the current partner and seeking another. Copulation alone doesn’t count. In humans, there’s emotional weight to social relationships, certainly to pair bonds.” she said.
The results of the study were published in the Proceedings of the National Academy of Sciences.
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