Human society is currently undergoing a socio-cultural ETI

An evolutionary transition in individuality (ETI) occurs when a previously independent organism becomes a lower level unit within a higher hierarchical level (for example, cells in an organism, ants in a colony). Based on archaeological and historical accounts from the last 12000 years, this article “Human societal development: is it an evolutionary transition in individuality?” builds the proposition that human society increasingly functions as a higher hierarchical level within which individuals integrate as lower level units. Human societal development is evaluated with respect to three criteria that together indicate complexity in biological systems and serve as an operationalization scheme for ETIs: size, inseparability and specialization. The size of the largest polity has increased seven orders of magnitude, from hundreds to billions. Inseparability became nearly complete since Mesopotamian city-states, following the first appearance of intricate specialization (division of labour). Connectivity within a polity has increased rapidly during the last few centuries, and particularly within the last few decades.
In view of these results, the following hypothesis is formulated: human society is undergoing an evolutionary transition in individuality, driven by socio-cultural-technological processes. This proposition requires a detailed theoretical basis and further empirical testing.

The emergence of novel levels of individuality is a recurrent theme in the history of life. Biological units that previously existed as independent individuals are incorporated within a higher level of organization, which becomes a new individual. For example, multicellular organisms comprise cells whose ancestors were individual unicellular organisms. Another example is the transition of individual organisms into a eusocial colony, as illustrated by ants and some bees, naked mole rats and marine invertebrates. The whole colony is arguably a single individual, and the ants or bees can be viewed as the mobile equivalents of cells in an organism. These phenomena are termed evolutionary transitions in individuality (ETIs).
Herbert Spencer conceptualized society as an organism, and based much of his sociological theory on this notion. Since the mid-1990s, in view of the increased complexity of human society, some scientists suggested that humans may be undergoing an ETI in which human society becomes a new hierarchical level of organization, positioned above the level of the individual person. The organism-like complex society is sometimes referred to as a superorganism.

The notion of humans becoming lower level units of a new hierarchical level above the individual is often rejected for various reasons:
(i) individual cells and individual organisms that have undergone an ETI to become a multicellular organism or social colony, respectively, are characterized by their relatively low learning capacity and limited behavioural flexibility. By contrast, humans have vast behavioural flexibility; they are fully aware of themselves and their environment, and they care for their freedom, which, it is argued, make them inappropriate candidates for an ETI;
(ii) humans are characterized by selfishness, conflict and competition, which may offset their capacity for the levels of cooperation required to undergo an ETI; and
(iii) cultural evolution has previously favoured human cooperative behaviour. Such favouring diminishes when group size and group interdependence increase to the point that individuals have divided loyalties to multiple groups in many dimensions simultaneously.

The various stages of ETIs entail an increase in system complexity. Thus, the operationalization scheme was organized around the concept of complexity, based on the assumption that complexity increases during an ETI. This scheme revealed processes that are common across different evolutionary lines and even across different ETI types. The selection criteria required that the scheme’s parameters be
(i) generable and applicable to any ETI, and
(ii) robustly estimable for diverse biological entities as well as various human societies. The resulting operationalization scheme consists of the following three criteria: size, specialization and inseparability.

(i)	size is the number of lower level units within a higher level entity. It can be the number of cells in an organism, or the number of ants in a colony. In the context of human societies, it is the number of individual members within a single society (a polity: tribe, chiefdom, city-state, nation or empire). Size was found to be correlated with complexity in multicellular organisms and in social insect colonies. In the context of human societies, the size of a society affects the rate of its cultural evolution; thus, an increase in societal size corresponds to an increase in the generation of useful novelties. Additionally, large societies may undergo specialization more readily than small societies; size could thus be a strong indicator of ETI in humans, similarly to its role in other ETIs;
(ii)	specialization (also termed ‘division of labour’) relates to the degree of variability in structure and function of the lower level units. As specialization develops, the lower level units (cells of an organism or members of a society) become more dependent on each other and complexity increases. In the context of humans, specialization may be estimated roughly as the number of unique occupations within a society. Individuals may switch their professions several times during their lifetime, and specialization is typically reversible. This is still in sharp contrast with a non-specialized society, where all members perform all tasks of daily life; and
(iii)	inseparability is the incapacity of lower level units (cells, individuals and subgroups) to survive and complete their life cycle separately, that is, independently of the higher level entity. In the context of human society, inseparability is the incapacity of individual persons or small subgroups to separate from a society, to survive, and reproduce entirely isolated from- and wholly independently of other societies. In group-living animals such as wolves, lions, gorilla and chimpanzees, individuals often disperse, and (with a bit of luck) find mates and form new groups, which are entirely independent of, and isolated from their former groups (= full separability). Inseparability dictates that individuals can only survive and reproduce as parts of a society. In this sense, the onset of inseparability marks a crucial point in the course of an ETI.

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“Cultural evolution drives human societies into a socio-cultural ETI.” This notion provokes diverse reactions, ranging from resentment to contentment. Some of the discontent may stem from a world-view of humans as independent intelligent entities and may not easily give up their individuality; the present hypothesis challenges this view.
For biologists, the notion of a socio-cultural ETI is challenging for another reason, though. The societal transition differs substantially from biological ETIs in at least two fundamental aspects:
(i) in addition to humans, intangible entities such as memes, cultural traditions, and possibly AI elements may come to play important roles; conceptualizing such a transition involves interactions between biological- and non-biological elements; and
(ii) unlike biological entities, human societal structure does not fit the standard framework of a single higher level entity enveloping its lower level units. Each individual may have several affinities to several nested- and non-nested higher level entities simultaneously.

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Application of the ETI operationalization scheme described above to human societies over the last 12 000 years revealed changes in all three parameters.

Size. The size of the largest social unit or polity increased by seven orders of magnitude (approx. 10 million-fold) during this period. This increase was nonlinear, with the largest polity growing dramatically from thousands to millions over the 1300 years from 5.8 to 4.5 kyr BP, but taking another 4400 years to increase from millions to billions. Similarly, in all ETIs, the size of the higher level entity increased by several orders of magnitude.

Specialization. There was very little division of labour in hunter–gatherer societies and early farmer societies. A radical and swift change occurred in Mesopotamian city-states 5.8–5.1 kyr BP, with the emergence of more than ten types of professions. Since then, the number of professions and occupations increased to dozens, then hundreds, and most recently to thousands, indicating a consistent increase in specialization.

Population size and specialization are correlated in human societies, similarly to the situation in multicellular organisms and insect colonies. However, differences between human societies and biological ETIs occur with respect to the specific type of specialization. The initial specialization in biological ETIs is reproductive. In earliest multicellular organisms, the first differentiation between cell types is between somatic- and reproductive cells; similarly, the first differentiation in eusocial insect communities is between queen and sterile workers. These specializations occur in functional units sized in the hundreds, whereas other specializations occur much later in the ETI process, in entities larger than millions. By contrast, the results of this study show that non-reproductive specializations appear in all human societies larger than a few thousand individuals, whereas reproductive specialization has not occurred even in a society of billions.
This difference stems from the essential difference between biological ETIs and the hypothesized socio-cultural ETI. Reproductive specialization is not required for socio-cultural ETI.
In socio-cultural ETI, information propagation is not only vertical (as in genetic transmission in biological evolution), but also horizontal (between non-kin society members). This implies a much faster, yet less accurate, information transmission, resulting in rapid and divergent evolution. In biological evolution, the progress of ETIs may take millions of years; by contrast, socio-cultural ETI advances much faster. In genetic-inheritance systems, specialization is first and foremost reproductive, whereas in socio-cultural ETI, specialization is first and solely non-reproductive.

Inseparability. Once elaborate specialization emerges in a society, single individuals and small subgroups lack the knowledge required to construct a new society on their own. Since the first profound specialization of human societies in the sixth millennium BP, barriers to separation rose ever higher, rendering city-states, kingdoms and nations effectively inseparable.

Inseparability, a causal driver of biological ETIs, may have contributed also to the socio-cultural ETI. In a society with complete inseparability, the fate of an individual is completely dependent on the fate of its society. As a result, selective pressures on individuals decrease and selective pressures on the society (tribe/band) rise. The society as a whole becomes the primary unit of selection. Some societies may die out, or may be absorbed into stronger societies. These selective pressures increase the mean size of the society, enhance its efficiency and promote technological innovations.

In addition to these criteria, it was suggested that increased connectivity between lower level units (here, humans in a society) may indicate increased integration of the emerging higher level organism. Connectivity is difficult to quantify in organisms as well as within societies; it seems, however, that connectivity between society members has increased in recent centuries, and particularly since the invention of communication technologies such as the telephone, internet, etc.

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Based on the abovementioned hypothesis, it is predicted that four additional traits change with increasing social complexity:

(i)	the level of regulation and control that society exerts over its members should increase. ETIs always begin with independent organisms that combine into a novel collective entity; the newly emerging entity initially has very little control over its constituents, as control mechanisms have not yet developed. As the transition progresses, control by the higher level entity over its lower level units may have strong selective advantages compared with entities that lack such central control. Hence, I predict that, as the socio-cultural ETI progresses, societal control over its members will rise correspondingly. The reverse, reduced control, is expected to emerge not gradually, but rather suddenly, propelled by a collapse, such as may occur following take-over by other societies, internal splintering, or severe natural disasters. One could evaluate increased control using various proxies, such as the number of new regulations per year;
(ii)	the extent to which the individual’s basic needs (food, health and personal safety) are met by society should increase in terms of the number of different needs covered and/or the degree to which they are fulfilled. One indirect measure of this is fluctuations in the number of distinct ministries and departments in governments over time;
(iii)	the proportion of conflicts between an individual and society that are settled in favour of society should increase. This could be estimated by surveying the outcome of ‘state versus individual x’ trials; and
(iv)	the strength of the relationship between climate and population size should diminish, because as society becomes more complex, its care for its members rises, and therefore their fate is less impacted by environmental conditions and more by how the society fares as a whole.

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The notion that human societies have become increasingly complex is widely agreed upon. The implications of this process for humans as individuals are contested. A prevailing view regards human society as empowering the individual. As societies grow and develop ever-stronger control, the situation of the individual improves in terms of personal safety, assured meeting of physical needs (water, food, clothes and housing), enhanced freedom, reduced war and better education.

In the opposing view, society increasingly controls and minimizes the autonomy of its individual members in a process termed by McShea ‘machinification’. This view is particularly prominent in literature and the arts, notably in the works of Franz Kafka, George Orwell, Aldous Huxley, Kurt Vonnegut and Charlie Chaplin, but also in academic publications. Recently, even liberal and democratic states have evinced symptoms of rising authoritarianism, that is, increased societal control over the individual.

Interestingly, both views are backed by voluminous evidence. On the one hand, societies protect their members from mishaps arising from the external environment. The proportion of humans directly affected by murders, famine, and even war decreases with time. Governments are able to protect their citizens more effectively than in the past, even in the case of major societal perturbations such as the current COVID pandemic. Similarly, cells gain increased protection when incorporated into an emerging multicellular organism. On the other hand, rising control by governments over their citizens is obvious, even if far from universally welcomed. These two contrasting trends may actually be complementary expressions of the same process: society becomes more cohesive, centralized and effective.
Society increasingly meets its members’ needs, while simultaneously exerting tighter control over them at the group and individual levels. Interestingly, both views are consistent with the hypothesis that human society is currently undergoing a socio-cultural ETI.