Just as birds became specialists in the spatial ecology of the air, primates became specialists in the emotional ecology of the dynamic hierarchies of their groups. Far from physical, this ecology consists of a publicly held registry of a group’s most recent social interactions. In Baboon Metaphysics: The Evolution of a Social Mind (2007), authors Dorothy Cheney and Robert Seyfarth determined that every single baboon knows exactly where he or she ranks at a particular moment in time, in their somewhat fluid hierarchies of about one hundred animals—and all behave according to the hierarchical rules of submitting to those who are dominant and dominating those submissive. Humans clearly live in the primate world of hierarchies, but the important part of human nature is not how we are similar to apes, but how and why our social behavior became so different and biologically unique.
Becoming Human: A Theory of Ontogeny, was published in 2019 by Michael Tomasello, a prominent investigator of the evolution of the mind. The book has crystalized the knowledge of a field in flux. Tomasello recognizes that the mystery of how the ape mind evolved into the human mind cannot be directly studied because “collaboration, communication, and thinking do not fossilize.” He approaches the problem by studying comparatively the minds of apes and developing children to ascertain what is exclusively human in human nature. He proposes that collective intentionality (will) in communication is unique to humans, and that it has genetic roots and is not merely a by-product of culture. He has come to this conclusion based on the predictable timing across cultures of the unfolding of 1) shared intentionality arising at nine months old (“Let’s both look at that pretty bird”) and 2) collective intentionality starting around three years old (“That’s the right way we ought to do it”).
Tomasello assumes that collective intentionality was evolved for the benefits of collaborative foraging, and that the vast refinement of teamwork is the unique human adaptation. He then makes the claim that this human capacity to collectively coordinate group behavior was a major biological “transition” tantamount to the Cambrian Explosion of life some 500 million years ago when cells assembled into multicellular organisms. Just as individual cells assembled into organically coordinated groups of cells, ape individuals assembled into organically coordinated groups of humans.
The key is to draw the distinction between cooperation, in which each party co-opts something from the other in a win-win “game,” and coordination, in which the synchronized engagement of divided labor leaves no room for individual–group trade-offs, and everyone rises and falls together. This watershed was crossed in both the Cambrian and human transitions when the benefits to the individual cell or ape of pursuing its own goals were overtaken by the benefits to each of coordinating their behavior as a group.
At a tipping point, disruptive competitive inclinations of individuals begin to be suppressed by natural selection for the coordination of each individual’s labor into a harmonious team effort. Once past this tipping point, there is exponential growth in the productivity of teamwork, and natural selection for benefits to the individual, even as a stealthy predator, is quickly overwhelmed by natural selection for benefits to relationships among individuals. The central theater of this evolution became a unique communication system (language) to mediate the coordination of groups of individuals as if they were single organisms. Human language is characterized by continuous-and-simultaneous signaling-and-receiving-signals, i.e., humans decide what to do as a group by constantly collaborating with each other.
The following outline contains evidence for the hypothesis that the emergence of our hominin tribe six million years ago represented a major biological transition in the history of life. In bold-type below, the known facts of human evolution are reinterpreted to be primarily influenced by the emergence in evolution of the novel social structure of individuals assembling into group-organisms with burgeoning linguistic capacity to coordinate their divided labor into teamwork.
EARLY HUMANS: Consolidation of teamwork (6-2.5 million years ago)
- With the stress of a population collapse in apes (Prado-Martinez et al., 2013), the increased productivity of teamwork shifted intentionality from the sterility of individual dominance to the productivity of collective authority triggering the following adaptations.
- Upright posture, a costly adaptation due to lower back, knee and hip injury, enabled the face and upper body to become the publicly viewed instruments for the sustained-and-simultaneous signaling-and-receiving-signals necessary to coordinate minute-to-minute teamwork.
- In skeletal fossils of species found in different African environments, their feet, ribcage, spine, hands, and shoulders evolved at different rates, but they all were moving in the same direction (Berger, 2017). Why? Because they were all responding to the same social environment of collective motivations evolved for teamwork, which adapted to all physical environments.
- Large molar teeth (megadontia) were evolved for eating grasses in different African climates. True, grasses were generally abundant, but there was also no shortage of other grass-eating animals for potential predation (Ungar, 2017). Early hominins became herbivores because competition attendant to high-value meat diminished teamwork.
GENUS HOMO: justice and migration (2.5 million→300,000 years ago)
- Homo Genus eventually became predominant hunters because they refined instincts for justice as an “immune system” against individual dominance, a pathology for organic teamwork. Indeed, justice (punishing dominance) has been observed in far-flung existing hunter-gatherers, not influenced by wealth-creating agricultural practices, (Boehm, 1999).
- Homo peoples cared for their sick beyond that observed in apes (Lordkipanidze, 2006).
- Why did the stone tool industry 1) become uniformly wide-spread across continents and 2) continue to produce the same tear-shaped hand ax for 1.5 million years? To prevent territorial competition, the Homo peoples evolved ultra-migratory behavior that, along with climate fluctuation, homogenized the construction of the hand ax, plus evidence they were made in groups (Pitts and Roberts, 1988). So, along with butchering meat, stone tools functioned as a cohesive group activity reflecting their communication: all watching each other for the authority of how it should be done.
- Large brain size correlates with monogamy in animals because synchronizing the care of offspring (as in birds) takes more brain power than negotiating a hierarchy (Dunbar and Shultz, 2007). Accordingly, synchronizing the behavior of groups in the Homo peoples evolved unprecedented brain growth.
Homo sapiens, pre-culture: desire and amalgamation (300,000-40,000 years ago)
In his second great treatise about evolution, The Descent of Man, and Selection in Relation to Sex (1871), Charles Darwin theorized that sexual display—not just survival of the fittest—has been a major factor in human evolution. Examples of sexual display abound in nature, from birds’ feathers and songs to insects chirping away, all saying to each other, “Here I am . . . Where are you?” Yale ornithologist Richard Prum’s The Evolution of Beauty (2017) reestablished Darwin’s disputed claim that the evolution of our own Homo sapiens species is centrally characterized by sexual selection. Sexual selection for displays is reflected in our dating process whereby we sort through potential mates by our preferences for certain displays, many of which are aesthetic. The following is a fraction of manifold evidence for the vast influence of sexual selection in Homo sapiens:
- Examining the fossils of prior human (hominin) species, we find that the physical make-up of our present-day species (Homo sapiens), is more physically attractive and youthful looking to us. We are more slender (“gracile”) than our predecessor species, and we have childlike skulls.
- Certain physical features of our species, such as rounded breasts in non-lactating females, and attractive behaviors such as singing, can be explained by dating-type selection.
- Besides stone tools, archaeologists have found shells and beads 100,000 years old that have been pierced presumably so they could be worn as jewelry.
- Humans value gold because it is malleable and its luster does not tarnish, thereby making it the ideal body ornament.
- The major motivation behind social media is not to exchange useful information, but to display to others the attractiveness of one’s life, food, pets, family, creativity, etc.
Sexual selection is driven not by individual dominance as in primate hierarchies, nor by the collective justice required for the engagement of teamwork as in our ancestral human species, but by the desire to be desired by each other as individuals—what psychoanalysts call narcissism and biblical texts call vanity. The relentless pull of attraction affected by desire has amalgamated the populations of our species into progressively larger intercommunicating associations among individuals. The genomes of Neanderthals reveal that they were “highly inbred, . . . lived in small groups, and had lower genetic diversity (Prüfer, 2017) than those of 34,000-year-old Homo sapiens in which “a single social group . . . was part of a larger mating network, similar to contemporary hunter-gatherers” (Sikora, 2017). UCLA anthropologist Robert Boyd, a leading authority on the interaction of culture and evolution wrote, “Perhaps our complex culture does not stem from individual cognition but from the shared knowledge we construct in groups” (Culotta, 2010). I have arbitrarily chosen 40,000 years ago when cave art first appeared in Europe and Island Southeast Asia to approximate the onset of modern culture when practical knowledge was broadly enough sustained across generations to itself begin to rapidly evolve by natural selection.
Homo sapiens, post-culture: chronic war (40,000→2,500 years ago)
Humans arose six million years ago and proceeded to evolve by a mechanism very different from Darwin’s survival of the fittest scenario. The difficult and subtle part of fathoming this deepest aspect of our human nature is that, in our own species, made possible by rampant sexual-selection, Darwin’s vision of group selection has been decisive in carving out the recent dimensions of human nature. In the following passage from Darwin’s Descent of Man, note the word, “victorious.”
"There can be no doubt that a tribe including many members who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage, and sympathy, were always ready to give aid to each other and to sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection."
This idea that our prosocial instincts have evolved as the result of groups waging chronic war continues to be tainted in academia due to Hitler’s related notion of the superiority of the warlike Germanic peoples. Nevertheless, there is direct physical evidence of group violence in pre-historic times (Keeley, 1996), and a case has been made using diverse genetic and archeologic evidence for chronic war going back perhaps some 120,000 years (Bowles 2009)—but not in our ancestral species.
Our us-vs.-them penchant for competitive group identities is powerfully rooted in biology—no doubt bred into us precisely in the way Darwin described as the legacy of natural selection for temperaments evolved for winning wars. However, the message of this new human narrative is not that winning is the only thing, nor the most important thing, but the most recent thing in human nature (although chimpanzees also wage low-intensity war). All stages of human evolution must be considered as part of a narrative in which each stage variously interacts with those that came before.
Homo sapiens, modern: awakening (2,500 years ago→present)
So how do we understand the larger evolutionary movements of our current era? Our epoch began with what psychiatrist-philosopher Karl Jaspers called the Axial Age, which flowered around 500 BCE, when “the spiritual foundations of humanity were laid simultaneously and independently in China, India, Persia, Judea, and Greece.” The Axial Age was an awakening followed by progressive reassertion of deeply evolved instincts for justice and morality that had been overwhelmed by scores of thousands of years of intense grassroots selection for war-like mentalities. The gradual establishment of law (Hebrew, Roman, English common law, US Constitution) began to render war into “games” of politics and trade defined by hierarchical competition under the authority of rules. Then reemerging with the Enlightenment era has been the authority of truth, which had reigned supreme over six million years of collaboration within the countless tribes of our ancestral species, all in passionate deliberation as to which path would be the most righteous and correct way forward for all as if a single creature.
That we are a species at a crossroads is indicated by the other similarly successful species, the eusocial insects, mainly ants and bees. Genetic ancestral state reconstruction indicates that the eusocial insects were initially monogamous (Hughes, 2008). Our ancestral species must also have been monogamous as a corollary of natural selection for the most productive relationships. In his Social Conquest of Earth (2012), E. O. Wilson argues that ants shifted to Darwinian group selection when they first started building nests they had to defend—ushering in never-ending chronic war, which transformed them into their nightmarish social systems of sterile castes and queens. Are we headed down that path? Or are we undergoing a progressive awakening to our tribe’s ancient mission to transform the power of aggression into the bounty of communion.