The Social Conquest of Earth

Book Review: The Social Conquest of Earth by Edward O. Wilson (Kindle Edition 2012)

This is a fascinating foray into gene-culture co-evolution and multilevel selection which is the interplay of individual and group selection. It is also a history of eusocial evolution and provides an unparalleled background of the dynamics of human social evolution. Wilson is an accomplished biologist, an expert particularly on ant species. Much of the book is a comparison between humans and eusocial insects. He has also written much about social evolution through the years. His book – Sociobiology – was criticized due to the suggestion that some aggressive behaviors like racism may have a biological or evolutionary component but he has since changed his orientation.

In the introduction Wilson touches on the human condition through the work of the artist Paul Gauguin. His 12 ft wide masterpiece painted in Tahiti was called – ‘This painting is not an answer. It is a question.’ Wilson uses this as a starting point on his foray into discovering what forces of evolution make up human impulses and the human condition.

The first story bonds of tribes are in the creation myths. Each of countless clans and tribes of the past shared their creation stories as a bond. I sort of tend to disagree with Wilson’s conclusion that myth/religion and science can never be reconciled. Who knows really? Although I agree that science offers us the best chance for agreed upon knowing – I think that all knowledge is an approximation. Therefore I more definitely disagree with his dismissal of philosophy. Luckily it is the science part that is valuable in this book.

He notes that humans were quite vulnerable to extinction throughout much of their early history due to many factors: small bands, droughts, disease, etc. Eusocial insects such as ants, bees, wasps, and termites have been around for tens or hundreds of millions of years compared to our meager few million. They evolved at a slower pace and achieved a better balance with the overall ecosystems while we have come to dominate and threaten the very planet we inhabit. Humans are also a eusocial species, defined as a species where group members consist of multiple generations and are prone to perform altruistic acts as part of their division of labor. This is merely one similarity to the other eusocial species. There are many obvious differences. Our eusociality apparently came about in different ways. He lists these as altruism, cooperation, competition, domination, reciprocity, defection, and deceit. Insects have size constraints due to their skeletal structures and brain size constraints. This limited their mental development to the instinctual level.

Wilson likens the path of evolution to a maze where old corridors (niches) close while others open. He talks much about ‘preadaptation’ as predisposition favorable to precede certain adaptation. An example is the relative size and relative immobility of humans compared to eusocial insect species. Other ones mentioned for primates are specialization for life in the trees – large eyes with color vision, opposable thumbs and fingers for grasping, and things like bipedalism when life on the ground became prominent. Bipedalism allowed primates to carry food in the hands for considerable distances. Perhaps, he says, due to their 3D environment and complex feeding behaviors they began to develop larger brains. They also began to rely more on vision and less on smell. He states that bipedalism was key to the success of the prehumans called australopithecines. Three species of them were known in Africa and they travelled in small groups in the manner of hunter-gatherers. Later homo species developed long-distance running abilities, dropped body hair, and developed sweat glands. These adaptations increased survivability in the hot savanna environment. The ability to throw things, to utilize projectiles, he thinks is a cultural adaptation. A few chimps do it as well. The next step toward human eusociality he gives as the control of fire. Perhaps first seeing and searching for dead animals caught in brush fires and noticing their cooked flesh easier to remove led to harvesting fire for cooking. Fire allowed the gathering of groups at campsites. These were probably kin groups along with women from nearby groups as in modern hunter-gather societies. Campfire sites were used by most or all of the homo groups and thought to extend back about 1 million years. The basic similarity to eusocial insects is that the insects raised young in a nest that they defended and foraged for food away from the nest.

Homo habilis (1.8-1.6 mya) developed from australopithecines. Habilis had evolved teeth to better consume meat and this consumption likely began as humans ate large herbivores found dead or killed by other predators that they could chase off. Successful competition for food, the use of tools to dig roots, and the wile to outwit enemies, likely contributed to better survival. Increased meat in the diet may have been a major contributing factor to larger brain size for hominid species. Wilson suggests that hunting strategizing actually may have been an even bigger factor in brain size increase. Hunting in groups is rare among mammals, occurring mostly in our common-ancestored primates (chimps and bonobos), but also among lionesses, wolves, and wild dogs. Utilization of teamwork to get meat, a denser proteinated and efficient food source, likely led to bigger brains and gradually more complex social behavior. They, as well as other eusocial species, foraged from protected nests. The protected nest was a place to go from and return to, a place of gathering, or reconvening, which seems conducive to the development of social behavior. Having both meat hunters and vegetable gatherers in the group helped to develop division of labor and competition for greater share of food. Status in the group became more important. The ability to read the intentions of others was key to social intelligence (probably still is). Those with this ability could also better outwit and defeat competing tribes.

Next he lists the major pre-adaptations, each leading to the next, that lead to modern humans: 1) living on land, 2) large body size (allowed for a larger brain) compared to other eusocial species, 3) grasping hands to hold, climb, and manipulate things, unique to primates, allowed for technological development, 4) adding some meat to the diet, first from scavenged carcasses, then from hunting, 5) cooperation in harvesting meat which led to highly organized groups, 6) controlled use of fire which allowed for evolution of digestion of cooked meat and social sharing of prepared meals. Fire also lead to – 7) extended base campsites that could be defended like a nest, 8) division of labor.

Wilson favors natural selection as the force that allowed us to navigate the evolutionary maze. He cites his early fascination with kin selection and its result called inclusive fitness theory. Now he favors group selection rather than kin selection – the notion that the fitness of the group was the important factor rather than just the fitness of kin. The interplay of individual selection and group selection, what he calls multi-level selection, he thinks, is the natural selection mechanism of humans. This theory is not based on degrees of relatedness as in kin selection, but is simply an acknowledgement of the necessity of balancing the needs of the individual and the needs of the group. Early homo sapiens consisted of groups competing for resources. The most cooperative groups became the most successful and the fittest. He sees a tension between the forces of individual selection, generally self-interested, and group selection, generally altruistic. The needs of the group came to overcome the needs of the members, but also to overcome the selfish survival habits of the members. He sees it as a cost/benefit dynamic.

He thinks this clash of individual and group selection is responsible for the arising of culture among humans. In this scenario selfishness, cowardice, and hypocrisy are products of individual selection and virtue, honor, and duty are products of group selection.

Based on the value of group selection in determining group fitness, Wilson concludes that: “tribalism is a fundamental human trait.” Our group or tribal instincts are a product of group selection. Modern humans exist within a social world of multiple interlocking tribes with various focuses. He gives the fanaticism around team sports as an example of tribalism. Tribal members develop in-group or home team preferences. Wilson thinks we have some brain hardwiring to favor groupishness. Tribalism is perhaps a key to humanity’s history and practice of warfare. Wilson mentions the modern example of Rwanda where in 1994, about 800,000 people were slaughtered by knife and gun in about 100 days. Wilson emphasizes the warlike nature of humans and suggests our societies are hopelessly bound to war behavior as history has shown – but I tend to think we can evolve beyond such limitations. Tribal mortality rates through war and homicide among hunter-gatherers, past and present, and even among chimps are remarkably similar. One thing is certain – territorial aggression and protection have a vast history. Population growth and competition for resources can lead to aggression. He likens these to limiting factors affecting hierarchical populations in the food chain. Limiting factors tend to kick in instinctual behaviors in various species such as emigration or can be natural limiting factors such as starvation due to overgrazing after removal of a predator. The advent of Neolithic agriculture allowed much greater populations to be sustained but war and tribal instinct did not abate between differing tribes. Our tendency to ‘multiply and consume’ has brought us to the brink of biosphere collapse in modern times.

Homo erectus was possibly buffered against extinction by its great range. From 1.5 mya this ancestor of ours roamed much of the earth excluding Australia, the New World, and various islands. Homo sapiens developed diagnostic features rare among animals: use of language, music, prolonged childhood, concealed female genitalia and female ovulation, fast brain growth during early development, small teeth and slender body suited to an omnivorous diet, and a digestive system suited to eat food tenderized by cooking. Wilson also gives a history of the spread of anatomically modern humans out of Africa. After this exodus some 48-60,000 years ago there was an explosion of culture and creativity. There are 3 main hypotheses for this creativity: mutation, a gradual development that happened to culminate in this time period, and that cultural innovations occurred then relapsed as deteriorating climate caused shrinking population and hardship – then re-emerged in newer forms as climate improved. All three ideas may be reconciled. Wilson suggests this time period as one where human culture became autocatalytic – where one innovation made others possible. These innovations increased group fitness and survivability. I guess this would be the time when cultural evolution gained on and perhaps even later overtook purely biological evolution for our species. The biggest overall jump may have come in the Neolithic 10,000 years ago with the advent of agriculture. With it came food surpluses, trade, villages, and specialization. Wilson suggests that the roots of agriculture came much earlier – 45,000 years ago when game was driven and captured by starting fires. As a result of this they likely noticed that growth of certain plant species was enhanced after the fires and so deliberate burning and selection of certain plants enhanced by burning may have been practiced. This eventually led to plant and tree domestication which occurred close to the same time as agriculture and animal domestication. Fast-forwarding to modern times Wilson gives his opinion of artificial intelligence as possible on certain levels of memory, computation, and information processing – but unlikely to replace the magnificent human mind, our treasured biological heritage.

Among humans anthropologists recognize three levels of societies: generally egalitarian hunter-gatherer bands, chiefdoms, and states. These developed culturally rather than biologically and are based on size, expansion, degree of success in war, and resource availability. Hierarchies develop in more complex social systems for reasons of efficiency and order. Studies have found that variation in personality traits within an ethnic group is relatively consistent when comparing different groups. This suggests that while there are general differences in traits between ethnicities there is also variability within and so the effects of culture are stronger than the effects of biology in making people different. Similarity of genetic dispositions among differing peoples likely led to them coming to the same adaptations (ie. state formation, agriculture, animal domestication, and possibly writing) in different places independently of one another.  These happened at different times and speeds. According to Jared Diamond’s famed work, Guns, Germs, and Steel, the reason for this was chiefly geography and availability of resources.

Part III of the book covers the development of social insects. He notes that eusociality is rare. Protected dwellings with multigenerational inhabitants and outwardly altruistic division of labor, are features of eusociality. These adaptations give social insects their ability to dominate the earth in terms of sheer numbers. Leafcutter ants have complex social behaviors. They practice agriculture by using their feces as fertilizer to grow a specific fungus which feeds them. Other ants farm aphids, scale insects, and mealybugs much like humans farm dairy cows living mainly off of their honeydew (excrement and excess moisture), only killing them in famine times. The ants actually protect these sapsuckers from other predators. The ant/sapsucker symbioses are widespread and contribute much to overall ecosystem cohesiveness. Eusocial insects developed innovative symbiotic relationships to their environment that helped them succeed. The change in plant dominance from gymnosperms to angiosperms (seed producing plants)  increased the survivability of those angiosperms and their long-distance dispersal. These flowering plants then co-evolved with pollinating insects, birds, and bats. Seed eating ant species may also keep granaries for storing food, another social innovation. Social arrangements became genetically programmed in social insects with altruistic division of labor as in worker bees and ants bred by Queen and drones. Wilson goes on to show how inclusive fitness theory and selfish gene theory are incorrect in terms of eusocial insect genetics of the Queen and her phenotype. The colony can be likened as a single organism. Wilson sees individual selection (the Queen and her robots) rather than multilevel selection (interests of individual furthered by interests of colony) as the mechanism in social insects. This is still debatable apparently. He goes on to describe social insect evolution in great detail but the book’s details may be better remembered with some summary lists, charts, tables, or recaps.

He discusses how natural selection creates social instincts. He gives an interesting hypothetical example of alleles for birds to select nesting in oaks and then pines developed when oaks became scarce so that the selection yields adaptability to changing times and resource availability. This is an example of micro-evolution where dominance of a certain allele may prevail when necessary – first for some then in time for the species as a whole as adapters survive. The example is one of ‘phenotype plasticity’ based on genotype.

“Natural selection is usually multilevel: it acts on genes that prescribe targets at more than one level of biological organization, such as cell and organism, or organism and colony.”

He gives cancer as an example of when selection at the cellular level conflicts with selection at the level of the organism.

Wilson goes on to describe kin selection and inclusive fitness theory in detail and suggest that – reduction of discordance within a group by group selection (presumably survival of more concordant groups) is equally plausible. Altruism in eusocial species has often been desribed in terms of kin selection/inclusive fitness but he suggests that group selection is equally plausible regardless of kinship. He gives a possible example as the “floating strategies” of certain species where helpers move about nests helping in tasks regardless of kinship. Wilson suggests a new theory built in stages: First individuals come together to build and defend nests or colonies. This gives advantages to the group. He suggests that close genetic relatedness is a consequence rather than a cause of eusocial behavior.  The second stage is accumulation of other traits that favor eusociality like care of the brood in the nest. The third stage is the origin of eusocial alleles through mutation or already mutated immigrants to the nest. Social genes have yet to be found but there are some selection forces that lead to alarm calls or chemical signals. These may develop to the point where different castes in the nest exhibit different behaviors. The 4^th phase is identification of environmental forces driving group selection. Defense against enemies, predators, parasites, and rival nests is an example. 5^th and finally there is group selection between colonies which drives life cycles and specialized social behavior.

Next he investigates human nature. He states that:

“Human nature is the inherited regularities of mental development common to our species. They are the “epigenetic rules,” which evolved by the interaction of genetic and cultural evolution that occurred over a long period in deep prehistory.”

Epigenetic means that the behaviors are not genetically hardwired or beyond conscious control but are tendencies based on both genetics and culture. The behaviors are not hardwired like reflexes but the rules are, he says. The behaviors are learned but we have predispositions (epigenetic rules) that prepare us to learn them. This process is an example of gene-culture coevolution. He gives the classic example as the development of lactose tolerance among human adults some few thousand years ago. The mutations caused production of lactase, an enzyme that converts sugar into lactose, to extend beyond infants into adulthood. This was precipitated by the cultural practice of herding and keeping livestock for milk. Lactose tolerance is an example of “niche construction.”

He gives another example of an epigenetic rule as incest taboo and subsequent exogamy (mating out of tribe). Another is color vocabulary, which rather strangely, it has been determined that our defined colors are learned rather than inherent, and also based on our ability to perceive certain wavelengths of light and not others. We learn colors but we learn them based on our genetic limitations. It has been found that language affects color classification. Another observation is that the color red in primates was noticed as it was often fruit to primates in a green and brown environment. Later it also became the color of sexual advertisement.

Wilson says that we did not invent culture but the common ancestors of chimps and prehumans did. We merely elaborated on it. Scientists define culture as “the combination of traits that distinguishes one group from another.” Culture traits are behaviors invented in a group or learned from another group. Among animals, chimps and bonobos have the most advanced cultural repertoire consisting of many culture traits. Humans utilize their unique long-term memory to vastly elaborate culture. Other animals such as pigeons and baboons exhibit long-term memory but humans are vastly better at it. Humans also have the unique ability to build scenarios which may be built from the memory. Wilson thinks that “the conscious mind, one of the architecture’s products [complex inherited architecture of the brain], originated by gene-culture coevolution, an intricate interplay between genetic and cultural evolution.” Archeological artifacts suggest that “abstract thought and syntactical language emerged no later than 70,000 years ago. Since 200,000 years ago hafting of stones onto spears suggests advanced cognitive ability. Both Neanderthals and Homo sapiens did this.

The ability to collaborate to achieve shared goals and intentions required the use of memory and cognitive abilities. Expressing our intentions and reading the intentions of others allows us to pursue our collaborative urges. Milestones were possibly the development of “shared attention” – the ability to pay attention to the same things as others, and the recognition that our own mental states are shared by others. These possibly aided the development of language. Language was the grail of social evolution, he notes. Language is a means to direct the attention of others and allows us to understand and share intentions, says linguist Michael Tomasello et al. Animals communicate with warning systems and some meaning conveyed but the communication is fixed. Human language has many nuances and abstractions. Language development may be aided as well by epigenetic rules (prepared learning). An interesting example is that in tropical climates languages appear to utilize more vowel sounds possibly due to acoustic efficiency where people spend more time outside and can hear those sounds better from a distance in competition with other sounds. The genetic basis of language likely predates language, say current researchers. 

Wilson compares rigid traits to traits having variability and plasticity. An example of plasticity is the uniqueness of human fingerprints and an example of rigidity is the amount of fingers on a human hand. Degree of plasticity in gene expression is apparently ruled by natural selection as well. Regulatory genes rather than coding genes are key to the evolution of plasticity. This results in more subtle effects on the whole organism. Wilson states that:

“The intricacies of gene-culture coevolution are fundamental to understanding the human condition.”

He examines the origins of morality and honor seeing them as a product of multilevel selection. “In a constantly changing world we need the flexibility that only imperfection provides.” He says that group selection results in in-group altruism. Individual selection is influenced by competition within a group while group selection is influenced by competition between groups. He offers a rule in genetic social evolution, that selfish people win out over altruistic people but groups of altruists beat groups of selfish humans. Multilevel selection, he says, is necessary as a way of balancing us between undesirable extremes. The history of social networks and the modern overlapping nature of multiple networks make for a complex of group selection processes. The band-sized network of our hunter-gatherer past is possibly our default network-size preference. The so-called Golden Rule is fundamental to moral reasoning in most or all cultures. The relationship to ‘others’ is key to this rule. The interplay of selfishness and altruism creates an ambiguous or ambivalent state. The needs and desires of the self seem to always be pitted against the needs and desires of others. I think Wilson goes a bit overboard in attributing altruism too much to biological and cultural influences. Altruism as a goal in itself can be cultivated as a habit and gradually become more genuine – and eventually spontaneous – according to Mahayana Buddhist training motifs. Honor as a motivation does seem to be influenced by both biological and cultural forces aided by the human will. Confronting injustice takes courage and will and is perhaps fed by a sense of honor, a desire to be honorable. Selfishness is often seen as dishonorable so in this way altruism can be motivated by a desire to avoid dishonor. Is this genuine altruism? It is probably not, so the degree of authentic honor cannot often be easily determined. Good intentions can also have detrimental consequences. Ethics can become dogmatic. He gives the example of homophobia. The origin is likely the notion that sex that is not for reproduction is undesirable and should be condemned. Homosexuality is often seen as genetic as well as cultural to a certain extent, yielding possible benefits to the reproductive success and preservation of human qualities within the group as well as contributions to human diversity. He says that: “A society that condemns homosexuality harms itself.” Wilson suggests that examining the biological origins of morality can be useful and will tend to verify the more obvious moral choices and tend to reject the ones based on fear and manipulation such as homophobia, racism, sexism, etc.

Religion initially makes conflict not between people but between worldviews. Wilson’s analysis of the origin of religion is interesting. He certainly favors secular science which I think is good but I also think he neglects some of the value of ritual, psychology, and philosophical contemplation. He rightly sees modern organized religion as an expression of tribalism. “The goal of religions is submission to the will and common good of the tribe.” He thinks Paleolithic peoples reflecting on their own mortality thought that the dead reappeared in dreams in spirit/dream worlds. Hallucinogenic drugs likely supported this belief. Working with them and incorporating them into the creation stories that knit the tribe together supported the development of mythology. Religion, he notes, has been incomparable in inspiring the creation of great works of art.

Compared to other animals and insects our sensory range is rather small, particularly in the realms of taste and smell. Humans, monkeys, apes, and birds are primarily audio-visual while other species communicate much with pheromones and chemicals. Of course, now we can probe the sensory ranges with our scientific tools. Experiments have shown that the human brain is most aroused by patterns with about 20% redundancy. This also apparently corresponds to the amount of redundancy and complexity in many human art pieces. Possibly this is the most complexity the brain can process instantly so that it is optimized in some sense.

Wilson suggests that the ambiguity in the human mind created by the conflict of individual selection and group selection is the key source of art and the humanities. He compares the mechanisms and rules of science and the humanities. He equates science with the quest for discovery in concise terms and literature with the use of metaphor which has the ability to communicate emotional tone. The whole analysis reminds me a bit of Nietzsche’s Apollo and Dionysus classification of human artistic impulses. Wilson attempts a quick history of artistic and creativity from early tools to the Paleolithic explosion of creativity. Flutes over 30,000 years old play just fine and are well constructed musically. The songs and dances of modern hunter-gathers are very often about hunting which could be compared to Paleolithic art in which hunting is the key subject. The songs are also tribal and strengthen memory of tribal history. He says that to create and perform music is instinctual and I am inclined to agree mostly to that. Music and language are related. Music may have been derived from speech as some suggest. Yet is also has beat which speech does not normally contain.

Wilson emphasizes the biological origins of culture. We are products of biological evolution. The question of free will – he suggests is more restricted to biology than is normally considered. Humans are the largest and most far-reaching eusocial species. He suggests that the forces of multilevel selection brought us to this godlike state. He considers group selection as the main driving force of human evolution:

“ … group-level traits, including cooperativeness, empathy, and patterns of networking, have been found to be heritable in humans …”

“A basic element of human nature is that people feel compelled to belong to groups and, having joined, consider them superior to competing groups.”

The conflicted nature of motivations and the pull of conscience can be explained by the competing nature of individual and group selection. Most creation myths favor that tribe as the chosen of the gods, over other tribes. Ritual helps to organize our tribal lives and aid in life’s transitions. But modern organized religion is often divisive and often does not consider well those of other orientations. Studies have shown that greater interconnection of people through such means as the internet strengthens their cosmopolitan attitudes – one can only hope. Strengthening a non-dogmatic approach to life can have positive repercussions such as allowing us to better work together to solve the problems of the world such as HIPPO (habitat destruction, invasive species, pollution, overpopulation, and overharvesting). Our dominance of the planet is shrinking biodiversity. He stresses the importance of recognizing science as the basis of our belief systems rather than just a scenario that is competitive with religious scenarios.

This is a great book that mainly explores the biological and to a lesser extent the cultural components of so-called human nature.