Evolutionary Anthropology

Evolutionary anthropology, too, can be defined in more or less limited ways. Narrowly understood, it is the branch of biological anthropol-ogy that concentrates on the evolutionary history of human lineage, which includes paleoanthropology and comparative primatology.

More broadly understood, it includes all evolutionary approaches to humans, including evolutionary functional considerations of human anatomy and physiology, as well as psychology, in which case it would include evolutionary psychology as well. In fact, biological an-thropologists often include evolutionary approaches to mind in their toolkit (see, for example, Deacon 1997 and Fisher 2016). But since the

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interest here lies in explaining behaviour, I will concentrate on the an-thropologists’ unique ways of explaining human behaviour with evo-lution directly, which includes research programmes such as behav-ioural ecology, theories of cultural evolution, dual inheritance theo-ries, and the niche construction theory of culture. But since our inter-est lies in evolutionary explanation of human behaviour as a biologi-cal phenomenon, broadly speaking, I will not include evolutionary change within specific institutional settings.^100,101

Historically, evolutionary thinking was a part of anthropology in its “progressivist” interpretation – that is, evolution was understood

100 “Special institutional settings” here would be things like a specific eco-nomic system such as free market capitalism (and the use of evolutionary game theory in understanding its dynamics; see Hargreaves Heap & Va-roufakis 1995) or science as an institution (for evolutionary perspective to sci-ence, see Hull 1988b). Fundamental issues regarding these models are, how-ever, presumably similar to what will be said about theories of cultural evo-lution in general.

101 Another way to distinguish between evolutionary psychology and evolu-tionary anthropology would be via reference to the encompassing institutional discipline – that is, whether it is psychology or anthropology. There are, how-ever, reasons to not to use this as a demarcation. First, there is a difference be-tween doing epistemology-driven philosophy of science and institution-driven sociology of science, implying different criteria for distinctions. Second, the rel-evance of institutional divisions to the analytic understanding of epistemic is-sues related to disciplines as epistemic projects is questionable. Sometimes the epistemic connections between two subfields of different disciplines may be stronger than the connections between subfields within the same institutional discipline. From an epistemic point of view both psychology and anthropology are divided into differentiated epistemic projects that are more like different disciplines than organized sub-disciplinary parts of the same discipline. Third, the institutional location of various evolutionary approaches is not unambigu-ous, as can be discovered by a quick look at the variation in the academic back-grounds and the institutional settings of the research performed by the practi-tioners of these various branches of evolutionary human sciences. But mostly, the focus here is on the methodology, not institutions, and the classification adopted reflects this, not institutional structures.

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as a progressive change towards more and more perfected forms, and different “cultures” (culturally different groups, typically identified with ethnic groups) were seen as more or less progressive in this sense. The various parts of anthropology studied different aspects of cultures that were seen as being at different stages of progress, and there were measures, for example, of different stages of linguistic evo-lution, the Western European languages being, naturally, on the top of the evolutionary scale. (Ingold 1995b.) When these ideas of progres-sion were abandoned (rightly so, from the evolutionary point of view as well), most of anthropology resigned from evolutionary considera-tions altogether. Biological (or physical) anthropology remained the sphere for evolutionary considerations, and cultural anthropology concentrated on the differences between cultures that were explaina-ble, basically, by their being of different cultures (Kuper 1999). Since the 1980s, however, evolutionary theory has made a comeback in the study of culture in three different ways: in behavioural ecology, in the dualistic gene-culture co-evolution, and what I will call the evolution of cultural representations, which includes several theories (e.g. memetics and epidemiology of representations).

4.3.1. Human Behavioural Ecology

Human behavioural ecology (for example, Chagnon & Irons 1979; Smith

& Winterhalder 1992; Krebs et al 1997; Cronk et al 2000; Borgerhoff Mulder & Schact 2012) is a branch of anthropology that approaches human social behaviour (such as mating and marriage, parenting, and moral practices) as an adaptive reaction to local ecological conditions.

It uses methods, concepts, and theories from evolutionary biology and sociobiology to do so, and it was partially an anthropological out-growth of these (see Laland & Brown 2002; Brown & Richerson 2013).

Unlike evolutionary psychology, it sees human behaviour as flexibly adaptable to different conditions, but unlike classical sociobiology, it does not bind this to genetic adaptation. One of the central theses of human behavioural ecology is the so-called phenotypic gambit (Grafen

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1984): the phenotype (behaviour) is approached as adaptive to its cur-rent ecological setting, but the means by which it adapts is left black-boxed. It is assumed that this adaptation is a combination of evolved psychology (including evolved environment-sensitive decision rules both on proximate and developmental dimension), cultural adapta-tion, and individual intelligence (and the use of other general cogni-tive capacities) to make the best of the environment. The emphasis is on the environment (hence “ecology”). The measure of the success is, however, the fitness effects of the behaviour, not just fulfilling the psy-chological needs of the individual or the group, making this a form of evolutionary functionalism. Human behavioural ecology uses the form of evolutionary functionalism I labelled as current utility analysis, in contrast to the artefact model of which some of the evolutionary psy-chology is an example, and the historical evolutionary functionalism that characterizes some of the evolutionary psychology and that classical sociobiology got stuck with. The anthropologist and behavioural ecol-ogist Monique Borgerhoff Mulder, for one, is quite straightforward on this point in constraining behavioural ecology to Tinbergen’s question about functionality and leaving the other questions to other fields of study, including social sciences (Borgerhoff Mulder 1991: 69). How-ever, anthropologists who use ecological tools do not restrict them-selves to this, and it is not unusual for them to study the proximate mechanisms too (see Brown et al 2011). Much of what human behav-ioural ecologists do in practice is regular anthropological fieldwork.

Human behavioural ecology is just an additional perspective that has become a school of its own.

4.3.2. Cultural Evolution

Social learning and culture are exceptionally important in human ad-aptation (Boyd, Richerson & Henrich 2011; Mathew & Perreault 2015).

Behavioural ecologists grant culture a significant role in human adapt-ability, but they do not study the mechanisms of or the basis for cul-tural evolution. The concept of culture is itself a contested concept.

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There is no unified view in cultural anthropology, for example, on how to define culture and what it is supposed to include: symbols, values, and representations only, or material products, technologies, and social structures as well? Is it something in the mind or in the ex-ternal (but socially transmitted) behaviour? Is it a characteristic of an individual or a group? Are there holistic “cultures” or more atomistic

“cultural features”? (Silverman 2002; see also Kuper 1999; Fox & King 2002b; Ramsey 2013b; Koskinen 2014.) Whatever it is, it is a non-ge-netic difference maker between different groups. For now, we can dis-tinguish between two concepts of culture that refer to this: culture as a medium and culture as content on this medium. Culture as a medium is the biological phenomenon of humans having cultures. It includes whatever capacities are needed for this (social learning and language, for example) and the fact that humans transfer “cultural things” using this medium. Culture as content includes whatever “things” that are transferred. The biological question of whether a species of animal has a culture and if so, what is the nature of this culture (for example, Hunt & Gray 2003; Laland & Galef 2009; St Clair & Rutz 2013; Ramsey 2013b). The controversies about culture in cultural anthropology are about the nature of the contents of this medium.

Biological anthropologists and primatologists are often more in-terested in the medium of culture and how it functions and constitutes a non-genetic route for traits to spread in the population (for example, de Waal 2001; see also Ramsey 2013b), although sometimes the capac-ity to generate behavioural differences between groups is mentioned (McGrew 1998: 305). There is also a further issue about the accumula-tion of the modificaaccumula-tion (Boyd & Richerson 1985; McGrew 1998; To-masello 1999; Carruthers 2013a) that may be required for genuine cul-tural evolution. The bioanthropological notion of a medium for socio-cultural transmission is what is meant by culture in this dissertation (with some further distinctions later on), and as for what kind of things belong to it, there is no harm in being an inclusive pluralist here. The important thing for the main issue is that how individuals behave in social situations is affected by what they have learned from other

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individuals, one way or another (for example, by copying behaviour, learning norms and attitudes, or developing meanings and beliefs that affect how the context is interpreted etc.). There are, however, theories about cultural change and cultural differences specifically.

One type of things that belong to culture are representations that are acquired from others and build our beliefs and affect our motives.

There are several theories that try to capture the evolution of cultural representations. Edward O. Wilson presented an idea of “culture genes” as an elaboration of sociobiology (Lumdsen & Wilson 1981), and Richard Dawkins (1982) presented the similar idea of memes, later developed into memetics by Susan Blackmore (1999). The general idea in these theories is that there is something analogical to genes that copy themselves from one mind to another, and there could be an evo-lutionary theory of cultural change. It is, however, difficult to capture the nature of the entity that is supposed to be the self-replicating unit that forms lineages (see Boyd & Richerson 2000; Sperber 2000; Sterelny 2006a; Lewens 2015). The lack of mechanistic detail in the theory leaves memetics explanatorily empty and merely an alternative narra-tive for cultural change (see Lewens 2015). A more sophisticated ver-sion of the same idea is Dan Sperber’s (1996) theory of the epidemiology of representations, which pays attention to culture-related cognition. Its main idea is that ideas, norms, et cetera are copied from human mind to human mind through communication, in which both the process of communication and interpretation bias what is transmitted, as do the characteristics of human cognitive architecture, such as what con-cepts, narratives et cetera are easy for us to understand and remember.

Human mind is the environment to which ideas must adapt, and the features of the human mind can explain, for example, what religious ideas are likely to emerge (Boyer 2001; Atran 2002). The epidemiology of representations is partly based on the evolutionary psychological understanding of mind, although what matters for it is only the un-derstanding of how mind works, not its evolution, and the researchers of the field are usually more interested in cross-cultural comparative psychology (or cognitive anthropology) than evolutionary psychologists

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proper who are more content with monocultural laboratory studies.

None of the evolutionary theories of cultural representations specify the connection between genetic and cultural evolution; they are theo-ries of cultural evolution only. Consequently, the relevance of these fields for the issue at hand is limited.

4.3.3. Genes and Culture in Interaction

Culture, as the medium, is a more significant issue. Culture in this sense is a product of evolution itself. In some cases, selection favours automatic reactions and fixedness of the behaviour, while in other cases, it favours developmental plasticity (West-Eberhard 2003). The forms of plasticity range from the triggering of a fixed and adapted, alternative developmental pathway by environmental conditions, to learning something new through individual creativity and intelli-gence. As a rule, learning is biased, directed, and constrained to some degree. The advantage of learning is the potential for novel behav-ioural responses during an individual’s lifetime, while genetic evolu-tion takes generaevolu-tions. Genetic evoluevolu-tion, however, selects behav-ioural responses according to their actual fitness benefits without the need for an individual considering, which has a higher risk for error, which makes genetic adaptation better than learning in most cases, if there is time to adapt. Individual learning and intelligence are fa-voured in conditions where constant and rapid adaptation to new cir-cumstances is needed. (Sterelny 2003.) Culture and social learning make behavioural change faster than genetic evolution and slower than individual learning; it allows cumulative learning that surpasses everything that an individual could accomplish, but it is also vulner-able to similar errors as individual learning – there is more time to correct, but the possibility of multigenerational accumulation of er-rors, too (Boyd et al 2011). Social learning and cumulative culture are evolutionarily useful only under quite specific context (for example, when a species is spread over a vast range of ecological conditions that change over time but stay the same for several generations, and there

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is gene flow between the groups). This is why social learning is rare in nature.¹⁰² (Boyd & Richerson 1985 & 2005; Boyd & Silk 2003.)

The specific contents of cultural representations also influence behaviour in ways that have fitness consequences. If the capacity for culture is evolved, it is to be expected that humans rely on social learn-ing and individual thinklearn-ing to different degrees in different contexts, and what and how is learned is constrained in ways that make evolu-tionary sense. Culturally invented and acquired capacities and habits may also become increasingly independent on external information in their development, if there is a selection pressure to acquire them ef-fectively, through the Baldwin effect.¹⁰³ All this means that the role cul-ture has played in human evolution should inform evolutionary ap-proaches of psychology, not only the other way around. But even on a shorter time scale, culturally acquired behaviour may have fitness consequences.

The theory of gene-culture co-evolution (or dual inheritance) (Boyd & Richerson 1985 & 2005; see also Durham 1995) explains hu-man behaviour as a product of interconnected genetic and cultural evolution. For the purposes of the theory, “culture” is defined as “in-formation capable of affecting individuals’ behaviour that they ac-quire from members of their species through teaching, imitation, and

102 New Caledonian crows seem to be the sole example of cumulative culture outside the human species (Hunt & Gray 2003; St. Clair & Rutz 2013). The lack of social learning is likely to be a matter of willingness to do so rather than the lack of the necessary cognitive capacities – this seems to be the case of the famous kea parrots, at least, who are able to learn by observing others but seem not to do so in nature (Gajdon et al 2004) – and there may be an evolu-tionary reason for this preference.

103 If a characteristic that is acquired is useful, more and more powerful ways to acquire it get selected, and genes that guide the development of the char-acteristic may be selected, too, if they emerge (Baldwin 1896; Futuyma 1998).

The same applies in the other direction as well: if a developmental resource is reliably available in the environment, genetic guidance of the developmental process may disappear.

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other forms of social transmission”, where information means “any kind of mental state, conscious or not” (Richerson & Boyd 2005: 5).

Social learning involving information transference is biased by both general and individual capacities and biases in learning, memory, and heuristics about who to copy from, but its assumptions about human psychology involve domain-general rather than domain-specific ca-pacities, in contrast to nativist evolutionary psychology (Sterelny 2012; Brown & Richerson 2013; Carruthers 2013a). The heuristics are biased in, for example, which individuals are more likely to be copied, based on their social status, perceived success, et cetera. These biases and other contextual differences in when to copy others are products of biological evolution: we have the tendency for social learning (and teaching) in the contexts where it has been evolutionarily more bene-ficial to rely on other than rely on one’s own thinking or (adapted) inclinations. This means that there is an evolutionary loop between cultural and genetic evolution: local cultures are evolving based on the biological success they bring, and the biological evolution of psy-chology is adapting to changing cultural conditions and the needs to rely on culture and social learning. Both cultural and genetic evolution are on-going processes, although cultural evolution is faster, as well as more directed, since new variation (produced by individual inno-vation) is directed, and transmission is biased (according to the behav-ioural trait’s content and context). However, if the dual inheritance theory has an approximately correct image of human evolution, it is important to understand that whatever species-typicality there is in human psychology, it is partly adapted to a socio-cultural environ-ment like this, and to an on-going cultural evolution and its needs.

The dual inheritance theory has three key features that make it a holistic approach. First, the cultural transmission is horizontal, har-monizing the behaviour on the group level, and relies on collective properties of the group (for example, the biases in who to copy from depend on the relative success and social status relative to other indi-viduals). Second, there is an idea of cumulative culture: behaviour, tech-nology, et cetera become more adapted, more sophisticated, and more

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complex from generation to generation, surpassing individual limita-tions. This may lead into behavioural traits that are increasingly de-pendent on the group level structures and interactions with others that make them holistic in the sense that I will discuss in the next two chapters in more detail. Third, the key idea in connecting culture and genes is cultural group selection. Despite the name, this involves not only selection between cultural groups (as cultural quasi-organisms), but it is also a form of biological (gene-based) group selection between groups that have different behavioural traits based on cultural differ-ences through the co-evolutionary loops described above.

4.3.4. Schools in Comparison

I will not discuss any of the “schools” of evolutionary human social sciences any further, nor will I try to evaluate them or discuss their compatibility. Any of them may be an adequate explanatory perspec-tive on some human behaviour¹⁰⁴, and much of human behaviour is probably such that the evolutionary perspective has nothing, or only trivial things, to say about it – but all this is a matter of empirical study and trial of various explanatory strategies. But there are some meth-odological issues that have come up and will be the topics of the fol-lowing chapters. First, the role played by evolutionary functionalist thinking is different in different schools, not just what they say about behaviour or its evolution. Classical sociobiology was a historical ad-aptationist project, and so is co-evolution theory. Some forms of evo-lutionary psychology also fall in this category, but some of it can be thought of as an artefact model instead, while behavioural ecology analyses behaviour from the current use perspective. Secondly, the very targets of the various evolutionary approaches seem to be

I will not discuss any of the “schools” of evolutionary human social sciences any further, nor will I try to evaluate them or discuss their compatibility. Any of them may be an adequate explanatory perspec-tive on some human behaviour¹⁰⁴, and much of human behaviour is probably such that the evolutionary perspective has nothing, or only trivial things, to say about it – but all this is a matter of empirical study and trial of various explanatory strategies. But there are some meth-odological issues that have come up and will be the topics of the fol-lowing chapters. First, the role played by evolutionary functionalist thinking is different in different schools, not just what they say about behaviour or its evolution. Classical sociobiology was a historical ad-aptationist project, and so is co-evolution theory. Some forms of evo-lutionary psychology also fall in this category, but some of it can be thought of as an artefact model instead, while behavioural ecology analyses behaviour from the current use perspective. Secondly, the very targets of the various evolutionary approaches seem to be