The evolutionary origins of human fatherhood

A week ago, I attended a lecture on fatherhood with other fathers at my son’s school. The lecturer has been an educator for decades and run school systems and Greenwich Country Day School.

He was quite interested in and well read on issues of genetics, nurture (family & parenting), and culture (social influences) as they relate to child development.

But he opened the Father’s Workshop by saying males are not biologically inclined to raise children, except perhaps in the earliest months. (In his view, only culture motivates fathers to act as fathers, which is what he urged us to do.)

While I admired his motivation, I disagreed with his premise, saying that what I have read on this subject suggests his claim is correct for many species but that humans, though not monogamous, are far closer to monogamy than most animals, including our nearest primate relatives, and that this is likely true because human parents must care for and teach their children for so many years and have evolved pair-bonding precisely to help our children (and grandchildren) thrive and pass their genes into the future.

Human fathers are instinctively, I believe, more bonded to their children than gorilla, chimp and bonobo fathers. My reading of the primatology literature confirms what my heart (and the logic of evolutionary biology applied to the human condition) tells me about the fatherhood impulse in humans being partly biological.

Coincidentally, just a few days later, New York Times writer Nicholas Wade wrote “New View of How Humans Moved Away From Apes”, based on fresh research on this exact question.

The [study of 32 living hunter-gatherer peoples] corroborates an influential new view of early human origins advanced by Bernard Chapais, a primatologist at the University of Montreal, in his book “Primeval Kinship” (2008). Dr. Chapais showed how a simple development, the emergence of a pair bond between male and female, would have allowed people to recognize their relatives, something chimps can do only to a limited extent. When family members dispersed to other bands, they would be recognized and neighboring bands would cooperate instead of fighting to the death as chimp groups do….

“If you take the promiscuity that is the main feature of chimp society, and replace it with pair bonding, you get many of the most important features of human society,” [Dr. Chapais] said.

Apparently, Wade finds the subject as fascinating as I do because he just wrote a follow-up article that digs deeper into this new theory. I summarize Wade’s synopsis as:

  • Bipedalism –> weapons –> monogamy –> fatherhood –> extended childhood –> larger brains –> increased importance of parenting

(Fatherhood, extended childhood, larger brains, and increased importance of parenting reinforce one another and likely fueled their mutual expansion.)

Here’s Wade’s summary:

Early humans began to walk on two legs because it was a more efficient way of getting around than knuckle-walking, the chimps’ method. But that happened to leave the hands free. Now they could gesture, or make tools.

It was a tool, in the form of a weapon, that made human society possible, in Dr. Chapais’s view. Among chimps, alpha males are physically dominant and can overpower any rival. But weapons are great equalizers. As soon as all males were armed, the cost of monopolizing a large number of females became a lot higher. In the incipient hominid society, females became allocated to males more equally. General polygyny became the rule, then general monogamy.

This trend led to the emergence of a critical change in sexual behavior: the replacement of the apes' orgiastic promiscuity with the pair bond between male and female. With only one mate, for the most part, a male had an incentive to guard her from other males to protect his paternity.

The pair bond was the pivotal event that opened the way to hominid evolution, in Dr. Chapais’s view. On the physiological level, having two parents around allowed the infants to be dependent for longer, a requirement for continued brain growth after birth. Through this archway, natural selection was able to drive up the volume of the human brain until it eventually reached three times that of a chimpanzee.

On the social level, the presence of both parents revealed the genealogical structure of the family, which is at least half hidden in chimp societies. A chimp knows who its mother and siblings are, because it grows up with them, but not its father or father’s relatives. So the neighboring bands to which female chimps disperse at puberty, avoiding incest, are perceived as full of strange males and treated with unremitting hostility.

In the incipient hominid line, males could recognize their sisters and daughters in neighboring bands. They could also figure out that the daughter’s or sister’s mate shared a common genetic interest in the welfare of the woman’s children. The neighboring males were no longer foes to be killed in sight — they were the in-laws.

The presence of female relatives in neighboring bands became for the first time a bridge between them. It also created a new and more complex social structure. The bands who exchanged women with each other learned to cooperate, forming a group or tribe that would protect its territory from other tribes.

I love fatherhood. I’ve eagerly read many books that have helped me be a better father. I enjoy reading with my kids, admiring their art, playing games with them, and trying to answer their (many) questions. I’m proud watching them grow up to be sharing, cheerful, responsible, engaged young people.

The claim that human fathers have no biological urge for fathering is absurd.

Posted by James on Tuesday, March 15, 2011