Back in the 1970s when he coined the term sociobiology Wilson was a proponent of individual inclusive fitness. Inclusive fitness is the view that natural selection acts on the level of genes which through the vehicle of the individual organism aim to pass themselves on to the next generation. The two forms of altruism that can occur with inclusive fitness are kin selection, direct benefit to relatives who share genes by different degrees, and reciprocal altruism in which one helps others for benefit in return, “you scratch my back I’ll scratch yours.”
Group selection also operates at a genetic level but sees genes as influencing individual behavior toward their social group which is a unit selected for genetic expression. Group selection was more widely accepted before the 1960s and 1970s when mathematical models of individual fitness proved themselves more useful. Since the 1990s however a repackaging of group selection has come about called multilevel selection, proposed by David Sloan Wilson (no relation to EO Wilson). Selection does occur on the individual level, but can also occur on the group level under certain conditions, hence multilevel. Genes they would argue already operate on different levels on individuals, whether it be protein formation or eye color. If groups are a concrete enough influence and compete with one another, then genes can be selected for individuals which orient them to the good of the group. Wilson seems to have switched his position because of his work with ant colonies and what to him seems to be research conflicting with inclusive fitness.
The case for multilevel selection as existing at all is the most interesting even for those who disagree. The best parts of the book are the middle and latter parts which discusses eusocial colonies. Eusocial means “true social”; organisms which behave and sacrifice their lives for the good of others. Hymenoptera (bees, wasps, termites, ants) are the best example of eusocial organisms in which their many members cooperate for the good of the hive/colony, sacrificing themselves in defense and not breeding, only the queen doing so. But as Wilson points out most organisms and even most insects aren’t eusocial. “The twenty thousand known species of eusocial insects, mostly ants bees wasps and termites, account for only 2 percent of the approximately one million known species of insects. Yet this tiny minority of species dominate the rest of the insects in their numbers, their weight, and their impact on the environment.” Eusociality is rare, but if the conditions are met, it can be very advantageous.
So what are the conditions for eusociality? There are two important preliminary steps: 1) a defensible nest, and, 2) multigenerational division of labor. Birds make the first step of having nests, but don’t stay around the young long enough for step 2. In an ant colony the queen stays and the workers forage for food. Multigenerational living is what creates the group. The parents or older generations stay with the young past childhood and exert a greater influence, create stronger bonds. Eusociality works because everyone in the colony is related, born of the queen. The insects aren’t altruistic the we think of it, they are really the “robotic extension of the mother’s genome.” The ants are the extended phenotype of the queen. A home to return to gives an incentive to work together, dividing the labor, as some must maintain the home and others to find food. Wilson admits this isn’t the altruism we think of, which is on the individual level and toward strangers for no benefit to the individual and instead a cost. But it demonstrates to him the possibility of the group level of selection.
Eusociality has further steps to become adaptive. 1) formation of groups 2) nest 3) alleles for eusocial traits 4) favorable environmental forces 5) group selection sufficient to produce changes. The third step is very important, the alleles which are altruistic must be capable of genetic selection. Flexible alleles capable of different expression help the division of labor. For these alleles to be selected favorable environmental forces must be present.
Wilson says that for humans these are large body size and limited mobility which make us dependent on each other. We need protection when traveling as we don’t go very fast on two legs, and females can’t easily leave and start their own family because of their limited mobility as well as that of the infant which can’t walk for at least a year. It takes a while to develop our big brains, so we go through a long period of physical dependency on others.
For vertebrates eusociality is extremely uncommon. Only the naked mole rat and, Wilson claims, humans have made it to true sociality. The case for human eusociality doesn’t actually begin with our big brains, as there isn’t a strong correlation between brain size and eusocial behavior. Apes are quite smart and have rudimentary social communication but aren’t truly altruistic.
So what are the causes/evidence for humans being eusocial? Humans have defensible campsites as well as multigenerational living. Having campsites is something predatory carnivore species like wolves and lions have, to return to after hunting and to protect offspring when away. Humans stuck around for a long time after the birth of children to raise them to maturity, which takes a long time. The argument is really that the transition to hunting life with the challenges of the last ice age are what changed us from a primate social order to eusociality because of a home base, greater male cooperation and investment in offspring, women raising children for a long period of time, growing brain size enabled by all of this and finally technological innovation with the control of fire and later agriculture. Humans live in social groups, though these were much smaller in Paleolithic times, 30 to 100. Likely it was that everybody in the group was related and being social also means excluding as well as including; non-kin. Having multigenerational living, an extended family, with a basic division of labor would be the factors inducing eusociality.
William Hamilton came up with the famous formula for inclusive fitness, rb>c; the degree of kinship to the altruist times the benefit to the recipient must be greater than the cost to the altruist for altruistic behavior to occur. Wilson reverses the equation and argues that sometimes organisms cooperate not because they are related genetically, but are related because they cooperate. The criticism Wilson sort of touches on is how the hell does an organism know it’s degree of relatedness to others? Also do organisms calculate the costs and benefits of every action? Most of this behavior in social encounters occurs without conscious choice, so something else is operating. It is genetic selection, but of what kind? The example in the book is the Westermarck effect; we aren’t as sexually attracted to people we grow up with. This is an example of behavior evolved for a specific social purpose which benefits the species, preventing incest. The effect applies to even non-kin if one is raised in close enough proximity early on. It is a pro-social adaptation which can operate without even knowledge of genetic relatedness.
What Wilson wants to argue for humans is that human altruism is genuine, rooted in our genes, and not just from relatedness or an extended phenotype. What seems to be going on is what is called coercive empathy or negative altruism. Emotions of stress and anger are produced when acting in certain nonadaptive selfish ways, so that one literally feels the pain inflicted onto others. Presumably this has to do with proposed mirror neurons which activate the same areas of the brain for certain activities we observe in others. The amygdala emotionally charges memories of our earliest relationships which form attachment patterns later in life. We feel pleasure at the punishment of those who don’t follow our expectations of behavior towards other, displacing our own anxieties which in turn reinforces our own expectations. All this is prior to the rational judgement of the cerebral cortex, which is above the amygdala-limbic system and evolved later. Some physiological adaptations like a visible white sclera, crying, and blushing make shame easier to induce as our emotions tend to follow what our body is doing. Individuals and groups would have their genes passed on because of these mechanisms/behaviors which benefit us in our social lives, rather than the genetic advantage leading us to as unconscious Machiavellians to manipulate people’s emotions.
The incentive for developing group selection is competition with other groups. If certain traits allow the group to outcompete another group for resource conflict, then they will pass their genes on.
I’ve thought of some mechanisms that would allow group selection to occur. All would have to increase the genetic relatedness of the group over time, relative to other groups. The most simple is reproductive isolation over time. People breeding amongst themselves for many generations will come to resemble each other genetically and in phenotype more than outsiders. They should favor those who look like them, because they are probably more related to them than other people. This we’d call ethnocentrism. This would work relative to other groups though, as individuals would still be as genetically related to others within their group as outsiders are related to their own ingroup. But greater competition with other groups would make the intragroup differences more salient and induce greater ethnocentrism. Presumably people would evolve different traits according to their environmental challenges over time other than just appearance which would differentiate them from and help compete with other groups:
-As humans moved latitudinally away from the equator’s tropical climate into colder territory, paternal investment would become greater. Women couldn’t gather year round, and men had to take up hunting meat. Those in the colder climate with changing seasons, eurasians, would develop: greater paternal investment, later sexual maturity, less sexual dimorphism, and greater intelligence to survive and plan in the regularly changing environment. Such persons would follow a K-selection reproductive strategy, K for competitive, which emphasizes quality of births over quantity, which is R-selection, R for rate.-
Consanguinity, marriage between first cousins, would make individuals more genetically related within the group than strangers within their groups. Polygamy, mostly polygyny of several females to a male, would also produce more genetic similarity and approach something like the eusocial condition of insects who reproduce from a single queen. Even when polygamy is proscribed, it occurs de facto with adultery, bastards, with particularly powerful men, and also divorce where the same man can have several children from different women.
Humans overall compared to other animals are moderately polygamous, serially monogamous, and are more K-selected. This differs between groups and would explain different survival strategies and levels of ethnocentrism.
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