Introduction

Chapter 1

Introduction

What should a sociology of humankind explain? Like scholars from other disciplines, most sociologists specialize in certain domains. They produce good results, but specialization makes answering domain spanning questions very difficult, and the ideal of including all peoples across times (Comte 1858) is not fulfilled. For example, sociologists observe culture (i.e., things that people learn from others) in many different social situations. This brings about many domain-specific theories but no general theory of cultural dynamics. Another example is cooperation, which is examined at protests, in lab experiments, and so on, without culminating in a general theory, even though domain specific cooperation could be more easily understood if there was one. A grand theory of everyone and everything is not feasible, however, because social life is too complex and diverse to explain on the basis of a finite set of principles. So we return to the question what a sociology of humankind should explain.

We may start with the phenomena that most affect the largest number of people and see how far we get. Because for most of what we do, we use knowledge that we learned from others, and it will not surprise that culture in the broadest sense should be among the first phenomena of interest. Additionally, most of what we achieve is with the (in)direct help of others, which puts cooperation in the same league as culture. People not only help and love each other (including voluntary sex), however, but also quarrel, hinder, and fight—often with enduring damage. Many of the largest problems we experience are due to conflicts of interest with close or distant others. This makes conflict our third core phenomenon. These three phenomena reveal (dynamic) patterns, and we can try to find principles that explain (the processes that lead to) them. Moreover, since all three phenomena occur in interactions between individuals and groups of individuals, a network approach can tie them together. Part of the information from others is about others; it is used to decide whom to avoid and with whom to cooperate, and information that tells who hinders may trigger aggressive actions.

In this book, I discuss culture, cooperation, and conflict over three hundred millennia of human history, as well as their relations to other important phenomena such as group dynamics, power, and social inequality. This long time frame enables scholars to recognize patterns that are missed in studies of current society. I aim for a handful of general principles, more coherence than the social sciences currently have, and more cross-domain exchange of ideas, but without the iron cage of a single paradigm for all social phenomena. Consequently, I draw no boundary between sociology and other disciplines; every insight is welcome. The linking pins for this endeavor are concepts, which are italicized in the text and defined in the glossary or on the spot. The overall structure of this book is historical, with forager, farmer, and industrial societies in chronological order. Historical patterns are interspersed with elaborations on explanatory principles. Cooperation and conflict each has a chapter of its own, and the principles of cultural dynamics are discussed in this chapter. Formal (usually computational) models of the core phenomena are in Chapter 8. None of the chapters can stand alone, however, and all are interrelated.

Whereas my approaches to cooperation and conflict will become clear on the way, my approach to culture requires an introduction. Culture is defined as “those aspects of thought, speech, action (meaning behavior), and artifacts which [are] learned and transmitted” (Cavalli-Sforza and Feldman 1981, p. 10). Cultural elements are thus shared by at least two people, but not necessarily among everyone (in a group); the number of people who share something depends on the process of transmission. For a general theory of cultural dynamics, we can start out with some principles that all social scientists likely agree upon.

First, new cultural elements are created by people combining incumbent cultural elements (Linton 1936; Burt 2004) by using their imagination and knowledge, sometimes serendipitously (Merton 1968). New cultural elements thus have cultural predecessors, and when putting all cultural bricolage (Levi-Strauss 1962) in one image, we obtain a treelike pattern (Linton 1949), from stone tools and fire at the tree trunk to trillions of leaves representing the cultural elements we have today. This pattern is illustrated in a drastically simplified form without combinations in Figure 1.1A, with time fanning out from the center. When we zoom in on a small part of this tree, thus moving from coarse to fine grain, the pattern, which now includes combinations, no longer looks treelike; see, for example, the evolution of the cornet (a horn invented in 1830) in Figure 1.1B. Each model of cornet was based on precursors, but some were also grounded in concurrent or older models (Temkin and Eldredge 2007). One could go on to complete the network of combinations by embedding it in the social network of individual inventors and users, as Collins (1998) did to some extent for philosophers who get ideas from other philosophers, but I will leave this exercise for another day. Once invented, cultural elements can be imitated by, or taught to, others who consider them valuable or who are forced to accept them by powerful people, thereby diffusing throughout parts of society (Rogers 2003; Pastor-Satorras et al. 2015). Thus, people obtain cultural elements through combination and transmission.

Second, people (learn to) use culture to navigate and prosper in their social and physical environments (Swidler 1986), even though some cultural elements harm them, for example, anti-vaxxer ideology that increases the chance of illness. After using cultural elements in (actual or imagined) interactions with others or with nature, people retain numerous elements, and discard others. Most of the cornets in Figure 1.1B that were initially appreciated are no longer produced or used. Regarding how transmission or use results in some cultural elements being outcompeted by others (that “compete for people”; Mark 2003), Schumpeter (1934) spoke about creative destruction. However, once cultural elements are internalized and embodied, i.e., become part of persons’ habitus (Bourdieu 1990), they tend to stick and become difficult to discard, especially when people become emotionally attached to them, for example, their mother tongue. When people are disappointed about a cultural element, they sometimes modify it or invent a new one; then, the principle of combination applies. Following Arthur (2009), I make no distinction between innovation and invention; both are novel combinations, at least from the point of view of the inventor(s). Many combinations, for example, standard phrases, are reproductions of what has been combined earlier (i.e., words) without novelty, though.

Third, all changes in the previous two steps, namely, combining, modifying, transmitting, using, and discarding elements, change the sociocultural and sometimes also the physical, including the natural, environment. The repertoire of elements available at any given moment constrains or facilitates further use (e.g., when cultural elements are interdependent), and impairs or encourages subsequent combinations, by which we come full circle. Therein, “we are all the agents and witnesses, as well as the beneficiaries and victims, of cultural change” (Cavalli-Sforza and Feldman 1981, p. 340).

Figure 1.1: Coarse and fine-grained structure of cultural evolution. (A) Tree. (B) Tangled tree with arrows in the direction of “inspired by,” not ordered along the timeline as in Temkin and Eldredge (2007), where the data come from.

These principles imply an evolutionary take on culture (Thurner et al. 2018), which is novel in sociology. Surprisingly, the concepts one might expect in an evolutionary approach—variation, reproduction, selection, adaptation, and fitness—have not been mentioned explicitly, although they are implied. Variation can be explained in terms of combination, but not every combination increases variation. Certain cultural elements such as standard phrases are frequently expressed identically, and their reproduction is a special case of combination (here, of words into phrases), namely, without increasing variation. Instead of the invisible hand of selection, the three-step model, comprising the three principles, is much clearer because it addresses specific interactions with particular consequences for the survival or disappearance of cultural elements and their users. This clarity carries over to adaptation: solving problems in certain situations or with respect to specific (groups of) individuals. Across the literature, fitness can mean chances of survival, life span, health, number of offspring, offspring that make it to adulthood, or number of grandchildren. Again, specific interactions with particular consequences are much clearer. The three-step model thus offers a more precise conceptualization of cultural evolution, but the familiar concepts can still be used if they cause no confusion, for example, if it is clear who selects what. The three main principles may then be summarized as combination and selection in a changing environment, like genetic evolution. In this process, culture evolves in a giant network wherein change is driven by people who combine, transmit, use, and select information under various constraints (like a scarcity of attention and resources), who do so cooperatively and competitively. Someone’s culture is someone else’s sociocultural environment, and everyone is surrounded by a cultural reservoir in the minds, behavior, and artifacts of many others that is continually updated.

Evolution is not deterministic and incorporates random chance, in serendipity and especially in the consequences of innovations. Many songs are written, but songwriters cannot intentionally compose songs that will make it to the top. People act intentionally, but they often lack understanding of the consequences of their actions, which depend on others, in particular on others’ cultural selection, again influenced by others. Furthermore, there are random errors in combination and transmission. Analogously, there is randomness in the evolution of genes. Although the causes of genetic mutations can sometimes be deterministic, e.g., a consequence of a chemical reaction, mutations are random with respect to the natural selection thereof.

With this three-step model, cultural dynamics can be mapped out in principle in a non-reductionist way, with every historical detail displayed in full color. The historical record has too many loopholes to accomplish this for long stretches of time, but we can discover general patterns. For example, many subsequent innovations are improvements of or complements to earlier innovations in the environment where they are used (Tarde 1890). People first discovered how to domesticate horses, then invented the saddle, and subsequently the stirrup. Any other sequence would have been literally unthinkable. Moreover, without knowing every individual cornet constructor, or culture creator in general, we can glean from Figure 1.1 that cultural evolution is roughly path dependent, meaning that one thing leads to another, corresponding to Darwin’s (1859) descent with modification. More precisely, cultural evolution is history dependent, as some elements from a longer past are reused. The overall treelike structure of culture is analogous to the tree of life, and both have gang planks where concurrent (and older cultural) information jumps branches, with many more gang planks in cultural than in genetic evolution (Zilhao 2019).

A cultural field where the evolutionary approach is applied extensively is language, based on detailed studies of corpora that span multiple centuries. These studies show that new words are constructed by modifying incumbent words (i.e., combining part of a word with a phoneme) and are transmitted from inventors to others who, through interactions in their social lives, select some words over others, thereby progressively changing the sociolinguistic environment, including its rules (Dunn et al. 2011). In the investigated cases, evolutionary forces, manifested by changing frequencies of use, were stronger than random changes (Newberry et al. 2017), and some new words or spelling outcompeted incumbents over a period of time (Amato et al. 2018). The temporal pattern of new word entry and incumbent decline closely resembles the pattern of social norm change (Centola et al. 2018), when a critical mass of new norm users wins over the remainder of the population. Languages are more than the sum of words, of course, and people spend years learning a language as a larger cultural package of grammar and vocabulary. Language changes, but different words and parts of a language change at different speeds. Frequently used words change slower than rarely used words (Pagel et al. 2007). For example, an irregular verb that is used 100 times more frequently than another one becomes regular 10 times slower (Lieberman et al. 2007). Interdependencies of rules slow down change, but rules are clustered into modules of more strongly interdependent rules such that change in one module (e.g., conjugation) is largely independent of rules in other modules (e.g., articles). The weak interdependence of language modules prevents most local changes from becoming disruptive overall. The social network of language users is also modular, because all social networks happen to be clustered in groups. If some groups become socially isolated, accents and dialects develop. Due to the adaptability that modularity offers in changing environments, with weak interdependencies between modules and strong interdependencies within, modularity is one of the most general evolutionary patterns and has been found in all natural and artificial systems that thrive in changing environments (Simon 1962; Alon 2003).  

Cultural evolution differs from genetic evolution because combinations of genetic elements are produced by a biochemical process, whereas combinations of cultural elements are made intentionally by people (although not always consciously). Furthermore, people have many cultural parents but only two biological parents, and unlike genes (yet) people collect their culture during their lives. They may forget some of their culture but cannot “forget” their genes. In most cases, culture can therefore adapt more rapidly than genes,3 and offers us a fair amount of behavioral plasticity. This may suggest that we have a great amount of cultural freedom, but there is more in some directions than in others (Tinbergen 1968). A norm proscribing adultery is much more difficult to maintain than a norm proscribing incest. We have certain dispositions with a genetic basis such as empathy for others, caring for one’s children and friends, and the desire to belong to a group, which are molded to certain but limited degrees in sociocultural settings. Moreover, when life is difficult, which was often the case for almost everyone before the 20th century, Darwinian selection leaves little room for doing spontaneously what one feels like without thinking; people who did “irrational” things instead of diligently caring for their children are not our ancestors (Pagel 2012). For material culture, there are physical constraints (Thompson 1917), for example, the laws of fluid dynamics that constrain the shape of boats (Rogers and Ehrlich 2008) and horns. Instead of seeing ourselves as culturally unbounded, realizing that we are primates in the tree of life and similar to other apes (Whiten et al. 1999) enables us to better understand our psychology and behavior.

Through the use of culture, especially agriculture, the natural environment changed considerably, as well as the natural selection of our genes (Richerson et al. 2010). An example is the control of fire and its use in cooking that are universal among humans (Goudsblom 1986), which not only changed the landscape through burning but also reduced chewing and digestion time, shortened our intestines, and flattened our bellies (Wrangham 2017). Another example is drinking milk from cattle, which was an advantage during periods of famine and disease and eventually led to lactose tolerance in adults (Evershed et al. 2022). In turn, genes shape our cognitive abilities to use culture. Genes and culture coevolve as two complementary information systems (Richerson and Boyd 2005; Mesoudi 2017), usually at a timescale too long for us to notice but no less influential. This evolutionary process is further complicated by ongoing selection of our social contacts and thereby changing network, which changes future chances of cultural combination, transmission, and use, as well as the survival chances of ourselves and our contacts. Evolution in general, encompassing both genetic and cultural evolution and their co-evolution, means transmitted and combined information5 that is selected in, and thereby changes, its environment. At this abstract level (and in the formal model), it does not matter if the information carriers use culture or are used by it (for genes, Dawkins (1976) believed the latter), although it is an interesting conundrum for philosophers, lawmakers, and social scientists. In the rest of this book, I will speak about culture users.

At this point, it is important to clarify what (co)evolutionary theory is not. It is not a grand theory of everything because without additional approaches, it cannot explain the origins of life, consciousness, and many other emergent phenomena (Thurner et al. 2018, p. 226). Further, it is not a theory of social Darwinism and Herbert Spencer’s ethnocentrism, teleology, and determinism, even though there is a small minority of racist scholars and numerous lay racists who distort and abuse evolutionary theory for their political purposes (Carlson et al. 2022; Morris 2022). Therefore, it remains important to stress that genes for skin pigmentation do not constrain someone’s talents or behavior–this happens through onlooking racists’ behavior. From birth to adulthood, most genetic influences on behavior are progressively modified, and in most cases eclipsed by cultural influences, except when bouts of unanticipated fear result in fight, flight, or stifling reactions, as well as bodily functions such as sneezing, yawning, and, most importantly, giving birth (notwithstanding the medicalization thereof). None of these have anything to do with “race,” which does not even exist biologically.7 Feminist scholars have rejected Darwin because of his misogyny, and understandably, I would say. After his famous book on evolution, he wrote another book, The Descent of Man and Selection in Relation to Sex, which avoided sex by all means but said that women are inferior to men and are basically incapable of making their own decisions (Darwin 1871). Modern biologists have explicitly rejected Darwin’s ideas about women (Rosenthal and Ryan 2022), however, and evolutionary theory does not hinge on the condescending passages in this book but on a large community with different ideas about women than he had at his time. In other passages in Descent, Darwin was far ahead of his time and against common opinion; he understood that humans are similar to, and not fundamentally different from, other animals and that humans come from Africa, not Europe. Furthermore, he noticed parallels between the evolution of languages and that of animals and said that culture has a stronger influence on human evolution than natural selection has. These insights were revolutionary at the time and have been confirmed by modern research (Richerson et al. 2021), hence they are worth keeping.

1.2 Goals and means

The goals of my Sociology of Humankind are fourfold, namely, to outline as-general-as-possible theories of culture, cooperation, and conflict, and to use these to connect specialists’ findings from numerous fields into a more coherent and more general sociology than we currently have. Fulfilling these goals requires a historical treatment, which occupies much of the remainder of this book. The historical record reveals instances of culture abundantly but incoherently. Cultural evolution demonstrates how each instance of culture is part of a large process that encompasses all instances, without Procrustean stretching or squeezing of the data. The more data are available, the more accurate an evolutionary reconstruction can be. Therefore, the criticism that an evolutionary approach does no more than putting old wine in new bottles misses the point. Evolutionary theory does not mess with the wine, but it attempts to systematically reconstruct the tree of old bottles to provide a bigger picture of how wine evolved. I will limit my treatment to broad trends over the last 300,000 years and leave the finer grained treatments of specific regions and times in the hands of historical experts.

At the micro level (which in sociology means interpersonal interactions), I use network theory (Kadushin 2012), which renders a broad range of relational and interactional approaches systematic and precise (Emirbayer 1997). Many interactions are neither cooperative nor conflicting, but most are cultural, if only because people use language to communicate with, and transmit information to, others. There remain interactions that are none of the three (or only to a very limited extent), for example, when people sense and bodily react to the presence of others nearby. Some of these interactions can become important, for example, when a confrontation between opponents turns violent. Another example is baby’s not-yet-cultural efforts to draw caregivers’ attention to their needs, which recruits the latter’s (culturally modified) helping behavior. I incorporate these non-, or precultural interactions in my treatments of cooperation and conflict. My primary evolutionary inspiration is the work of Peter Richerson and Robert Boyd (2005). Around their work, anthropology has a vibrant subfield (Mesoudi 2017), whereas sociological advocates and practitioners of cultural evolution and coevolution are few and far between (e.g., Parsons 1964; Allison 1992; Lenski 2005; Blute 2006).

The number of social scientists who use concepts consistent with or explicitly related to cultural evolution is much larger, such as cultural transmission (Hunzaker 2016; Kandel and Massey 2002), the dependence of network formation on its social environment (McFarland et al. 2014), the interplay of culture and networks (Vaisey and Lizardo 2010), and cultural influence on taste (Lieberson and Bell 1992). As a matter of fact, it turns out to be quite easy to interpret most empirical findings to a cultural evolutionary perspective and thereby relate them in a way of which the authors of these findings were unaware.

[…]