Primatologist Sarah Blaffer Hrdy says that while most scholars believe our evolution was driven by the need to fight, she believes that a human baby's need for attention is what separates us from animals.
In Hrdy's new book, Mothers and Others: The Evolutionary Origins of Mutual Understanding, which will be published next month, she argues that human babies are so dependent on adults for such a long time that humans could not survive under the ape model of child-rearing, as the NY Times explains. While chimpanzee and gorilla mothers can care for their children by themselves, human babies require so much attention that mothers must be assisted by other adults. This caused human evolution to favor traits that facilitate cooperative child rearing.
When human babies smile and coo they are demonstrating the tremendous social skills they are born with that attract even non-related adults to care for them. While most biologists agree that the need shared child care influenced human evolution, Hrdy says that this need, rather than having complex brains, is what caused humans to develop behaviors such as sharing, cooperation, and empathy, which are not as evolved in other species.
In an interview with the Times, Hrdy explains that she rejects the popular theory among her peers that humans' extremely social nature grew out of the need to cooperate within a group to wage war with outsiders.
Sure, humans have been notably violent and militaristic for the last 12,000 or so years, she said, when hunter-gatherers started settling down and defending territories, and populations started getting seriously dense. But before then? There weren't enough people around to wage wars. By the latest estimates, the average population size during the hundreds of thousands of years of human evolution that preceded the Neolithic Age may have been around 2,000 breeding adults. "What would humans have been fighting over?" Dr. Hrdy said. "They were too busy trying to keep themselves and their children alive."
Hrdy says that the human focus on group child rearing also contradicts the long-standing belief that humans are a patrilocal species, with women moving away from their families to join their husbands. She has concluded from analyzing new research in anthropology, genetics, infant development, and comparative biology, that in traditional societies women stayed near their female relatives, the people they could trust to care for their babies the best, meaning that, if Hrdy is right, a mother's need to care for her children, rather than conflict, is the driving force behind the development of the human species.
[Image via Monsters and Critics.]
In A Helpless Baby, The Roots Of Our Social Glue [The New York Times]