Males of almost all primate species, even chimps, guard females to some
extent, so as to deter other males and improve their own chances of
fathering the females’ children.
Among the population of chimp like
ancestors that had left the trees,
mate guarding
would have become more common than usual
because of the more dangerous environment on the ground.
With the male often around for defense, he could also help in feeding and taking care of the children.
Having at least two people involved in child rearing made an enormous difference, Chapais argues.
-
The period of juvenile dependence could
last for several years longer. - Children could be born at an earlier stage in their development since they would be more protected, and...
-
Earlier birth enabled the brain to do more of its
growing outside the womb. -
The human brain eventually reached three
times the size of that of chimps.
At first each male guarded as many females as he could, but another development drove them unwillingly toward monogamy.
This was the emergence of weapons. At first, physical strength was decisive in fending off other males. But weapons are great equalizers because they tend to negate the advantages of size.
-
The cost of maintaining a large harem
became too high for most males - Weapons forced most to settle for one wife.
- The pair bond between male and female
became established.
Having a dad around makes all the difference to social networks.
-
In highly promiscuous societies like those of chimps, an
individual knows only its mother and the siblings
it grows up with. -
With pair bonding, people know not only their
father as well as their mother, but all
their father’s relatives too. -
The males in a community now recognized both their
daughters and, when their daughters dispersed to a
neighboring group, a daughter’s husband and his parents.
The neighbors, who used to be treated as hostile, began now to be seen in an entirely different light.
Those males, who once had to be killed on sight, were not the enemy—they were the in-laws, with an equal interest in promoting the welfare of one’s daughter’s or sister’s children.Thus in the incipient human line, a new and more complex social structure came into being, that of the tribe, a group of bands bound to one another by exchange of women.Warfare between neighboring bands, the chimp practice, was now pushed upward to the
tribal level.Tribes would fight as savagely as before, but among the bands within each tribe cooperation was
now the rule.
This profound transition in social structure started some time after the split of the ancestral populations leading to chimps and humans.
-
Pair bonding, an essential element of the
new social structure,
probably did not become significant until the emergence
of Homo ergaster some 1.7 million years ago. -
This is the first human ancestor in which the males
were not very much larger than the females. -
A large size difference between
the sexes, as
in gorillas, indicates competition between
males and a harem structure. -
The size difference diminishes as
pair bonding becomes more
common.
Given the distinctiveness of chimp social behavior, there is no reason to doubt that it has a genetic basis.
Both the chimp and human lineages would have
inherited a suite of genes governing social behavior
and in each species the genes for social behavior
would have evolved as social structure changed in
response to the society’s requirements for survival.
A Troublesome Inheritance: Genes, Race and Human History
- Nicholas
Wade
http://www.amazon.com/Troublesome-Inheritance-Genes-Human-History/dp/1594204462
Primeval Kinship:
How Pair-Bonding Gave Birth to Human Society - Bernard Chapais
...Bernard Chapais shows that our knowledge about kinship and society in nonhuman primates supports, and informs, ideas first put forward by Claude Lévi-Strauss.
Chapais contends that only a few evolutionary steps were required to bridge the gap between the kinship structures of our closest relatives - chimpanzees and bonobos - and the human kinship configuration.
The pivotal event ...was the evolution of sexual alliances;
Pair-bonding transformed a social organization loosely based on kinship into one exhibiting the strong hold of kinship and affinity.
The implication is that
the gap between chimpanzee
societies and
pre-linguistic hominid societies
is narrower than we might think...
Reciprical Exogamy
Exogamy is the social practice of allowing marriage only outside the social group. It is "outbreeding" and it delivers to those who practice it a clear evolutionary benefit: offspring will be healthier and more likely to survive. Even oak trees have developed a means of practicing exogamy!
Reciprocal Exogamy is where two separate societies make an exchange of their women, one to the other.
Levi-Strauss' theory is commonly called the "Alliance Theory."
By this theory, weddings are not just parties celebrating
an emotional bond between 2 people, but are a
form of communication between two extended families.
Marriage, by this view,
creates complex webs of alliance*
*"affinity" is the technical term that stretch from the present (brothers, sisters, nieces, nephews), back into the past (mothers, fathers, grandfathers, etc.) and into the future (children, grandchildren, cousins, etc...
A new mating system based on enduring breeding bonds between males and females. The effect of that change on hominid society was like the effect of bipedal locomotion on the use of the hand.
Agnatic kinship emerged as a byproduct of the combination of stable breeding bonds with preexisting adaptations relating to uterine kinship. The stable breeding bond between a father and mother provided a reliable
means for the father to recognize his offspring
and for an offspring to recognize his father.
In this context. the cognitive abilities and developmental processes involved in the recognition of uterine kin enabled hominids to recognize their kin on the father's side. In short - old abilities were coopted for use ln a new context.
In retrospect - therefore, the abilities involved in the the recognition of uterine kin were preadapted for agnatic kinship recognition. ...already displayed by nonhuman primates where needed, in this sense, early hominids were cognitively preadapted to recognize their afïnes...
Following the evolution of pair-bonding, meetings between interbreeding groups provided opponunities for afïnes to come into contact. When a female born in group A and pair-bonded in group B came into contact with her natal kin living in group A. The "husband" was likely to meet with his wife's relatives, for example, his "father-in-law" and "brothers-in-law".
But why should relationships between affines be nonaggressive, peaceful, and even amicable to begin with? From an evolutionary perspective, the answer is straightforward:
- Such relationships were bound to be, fundamentally, relationships between potential allies.
- Affines, such as brothers-in-law, share a vested interest in the same female, one as a husband, the other as a brother.
- Both in-laws derive benefits from the female's well-being, the husband through his own reproductive interests and long-term cooperative bond with his wife, the brother by virtue of his genetic relatedness with her - through inclusive fitness benefits.
Crucially, this shared interest is not impeded, in fact not nullified, by sexual competition between the two males.
Owing to incest avoidance, a brother does not compete with his sister's "husbands" for sexual access to her.
Now two individuals who share a common concern for a third party's well-being and are not competitors for that third party are somewhat biased toward interacting positively with each other. To take an analogy, parents are allies in parental care because they share a vested interest in the same child, an interest unhampered by sexual competition, for that matter. They are bound to cooperate with each other even though their contribution to their child's well-being and the nature of their relationship with it may differ considerably:
Minimally, therefore, brothers-in- law shared a common interest in protecting the female who stood as wife to one and sister to the other. They were de facto partners. Moreover, brothers-in-law should have refrained from attacking each other if only because an attack on the brother the husband would prompt the sister to protect her brother, and an attack on the husband by the brother would prompt the wife to defend her husband. When defending her brother, a sister is in effect increasing her inclusive fitness benefits, and when defending her husband a wife is attending to her reproductive interests. It is precisely here that the expression "females as peacernakers" takes its fullest meaning. Females were more than mere links through which afïnes could become disproportionately familiar to each other; they were intermediaries and intercessors through which they could become allies and partners.
Primeval Kinship: How Pair-Bonding Gave Birth to Human Society
- Bernard
Chapais
http://www.amazon.com/Primeval-Kinship-Pair-Bonding-Birth-Society/dp/0674046412
The Pair Bond Instinct; Crucial to Chapais's evolutionary sequence is the development of pair-bonding (relatively stable mating bonds between males and females; what Fox called “alliance”) in the human line. Pair-bonding promoted a number of changes ultimately leading to the exogamy configuration. Indeed, Chapais likens the consequences of this new mating system on hominid society to “the effect of bipedal locomotion on the use of the hand” (p. 27). Among the changes fostered or further developed by pair-bonding are fatherhood, or father-offspring recognition, and agnatic kinship, or recognition of relations through the father. Pair-bonding and fatherhood further strengthened sibling ties. Pair-bonding was also crucial for the bilateral recognition of affines, “in-laws,” in a process that built upon cognitive abilities already present in primates. Chapais then provides a fascinating discussion of how consanguineal and affinal kinship recognition may have led to the formation of intergroup “appeasing bridges.” These bridges fostered peaceful relations between local groups, setting the stage for a later systematic exchange of mates that would unite affines within alliances.
Book Review: Kinship Back on Track: Primatology Unravels the Origin and Evolution of Human Kinship http://journals.sagepub.com/doi/full/10.1177/147470490800600402
Evolution of the Dad
https://knowablemagazine.org/article/living-world/2021/evolution-dad
Broadening Perspectives on the Evolution of Human Paternal Care and
Fathers’ Effects on Children | Annual Review of Anthropology
https://www.annualreviews.org/doi/10.1146/annurev-anthro-102218-011216
