## 1. Natural Selection and Culture



Darwin believed, as do biologists today, that natural selection can
explain the origin of many complex adaptive traits. In Darwin's
original presentation of natural selection, he requires that parent
organisms differ in their abilities to survive and reproduce, and that
offspring resemble their parents in terms of the traits that promote
or inhibit these abilities (Darwin 1859).



As many have noted--including Darwin--this explanatory
schema does not specify what mechanism accounts for parent-offspring
resemblance. For example, offspring might learn skills from their
parents, and thereby come to resemble them behaviorally. From the
perspective of natural selection explanations, it does not matter why
offspring resemble parents, only that they do resemble them. What is
more, the general schema associated with natural selection
explanations does not even require a population of reproducing
organisms: it applies under any circumstances where entities in one
generation give rise to resembling entities in a subsequent
generation. In this sense, it is *substrate-neutral*.



Darwin himself explicitly espouses the view that natural selection can
act on entities other than organisms in the context of the cultural
phenomenon of language change. This position is briefly explored in
the *Origin of Species*, and further expanded in the
*Descent of Man*. In this latter work, he endorses the opinion
of Max Muller:



> 
> 
> "A struggle for life is constantly going on amongst the words
> and grammatical forms in each language. The better, the shorter, the
> easier forms are constantly gaining the upper hand, and they owe their
> success to their own inherent virtue". (Darwin 1871: 60 [1877:
> 91], paraphrasing Muller 1870: 257)
> 
> 
> 



Darwin asserts that this is no mere metaphor or loose analogy:
"The survival or preservation of certain favoured words in the
struggle for existence is natural selection" (1870: 60-61
[1877: 91]).



The pursuit of the cultural evolutionary project does not stand or
fall with Muller's thought that there are close affinities
between processes of cultural change and the sorts of
processes--of which natural selection is an example--that
shape the organic world. Successful approaches can instead explore, in
whatever ways seem best for the task at hand, how learning makes a
difference to how species change and adapt over time. Nonetheless, as
a matter of fact, many cultural evolutionary theorists have made use
of explanatory concepts and models adapted from mainstream
evolutionary theory, and they have often justified this by arguing for
important isomorphisms between the domain of biology and the domain of
culture. Mesoudi (2011; Mesoudi, Whiten, & Laland 2006) is a
useful case-in-point, identifying not just "key Darwinian
properties" of variation, heritability, and selection, but also
pointing to disciplinary analogies between the study of cultural and
biological change.



Of course, drawing analogies between cultural change and biological
evolution far from settles philosophical questions about cultural
evolution (see the discussion of analogical models in the entry
 models in science).
 Many cultural evolutionary terms evade rigorous and exhaustive
explication. "Culture", "transmission", even
"evolution" merely gesture towards complex phenomena. This
provides latitude for researchers to fill in the analogical details
between culture and biology in different ways (Sereno 1991; Stanley
2021). What, for instance, is the "culture" that evolves?
What does it mean to evolve? And what mechanisms are involved? We
address these questions in subsequent sections.


## 2. What Evolves?


### 2.1 The Culture Concept



What evolves in cultural evolution? Philosophers and other researchers
have answered this question differently over the last hundred or so
years, with few signs of consensus (Sartori 2005; Descola 2005
[2013]). The term "culture" now supports a range of uses
in philosophy (See the entry on
 culture),
 the humanities (Kuper 1999; Risjord 2012) and empirical research
(Driscoll 2017; Feinman & Neitzel 2020; Mohr et al. 2019; Buskell
forthcoming). This widespread use facilitates different understandings
of the extension of "culture" and the kinds of processes
that might change it.



One important contrast distinguishes distinct *levels* of
cultural phenomena. Though it is quite common to refer to both
individual- and group-level phenomena as "culture", it
frequently leads to confusion. For example, it can lead to conflation
of talk about traits--things *actually* or
*possibly* possessed by individuals, such as the ability to
make a Cornish pasty or to speak the Cornish language--and
"the culture" of a group, as when one speaks of
"Cornish culture".



Cutting across the distinction in *levels* are distinct
possible *roles* for "culture" (Risjord 2012).
"Culture" might be a medium for carrying content; the
background conditions needed for meaningful practices to be undertaken
(Bourdieu 1972 [1977]; Ortner 1984; Rouse 2007); or the strategies
(behaviours, technologies) adopted to deal with local ecological
problems (White 1949; Steward 1955). Positions might be cut finer
still: researchers differ on the character of the content carried, on
the nature of practices, and the set of strategies that matter
(Risjord 2012).



There is, then, considerable variation in how the culture concept is
defined when one looks across disparate disciplines. If one focuses on
the community of researchers in cultural evolution, however, one finds
that Richerson and Boyd's (2005) definition of culture is fairly
typical. Culture, they say, is



> 
> 
> information capable of affecting individuals' behavior that they
> acquire from other members of their species through teaching,
> imitation, and other forms of social learning. (Richerson & Boyd
> 2005: 5)
> 
> 
> 



That is, "culture" is an individual-level phenomenon,
content ("information") is carried by a wide range of
material vehicles, and this content is communicated by a range of
transmission mechanisms. Though cultural evolutionary researchers
might talk about culture at the group-level, this tends to be an
*aggregate* measure or *generic* description of the
cultural information held by individuals in group, where the group
itself is delineated by other means (for instance, by ethnic identity,
e.g., Richerson et al. 2016; Henrich 2020. See: Buskell forthcoming
for discussion).



Adopting "information" as the underlying basis of culture
brings both risks and benefits (see related entries on
 information,
 and
 biological information).
 On the negative side, it is not clear how we are to understand the
concept of information. Boyd and Richerson, for example, give what
might look like a definition when they write that, by
"information", they mean



> 
> 
> any kind of mental state, conscious or not, that is acquired or
> modified by social learning and affects behavior. (Richerson &
> Boyd 2005: 5)
> 
> 
> 



But they later state that "some cultural information is stored
in artefacts" (2005: 61), suggesting their comments are intended
as a description of where most cultural information is to be found,
and not as a definition of what cultural information is. When they do
offer a definition, it invites obvious counterexamples. So, for
instance, in early work they write that information is
"something which has the property that energetically minor
causes have energetically major effects" (Boyd & Richerson
1985: 35). But the long training scientists undertake, and the large
amount of resources they might consume, to produce data and theories
(often, in the form of written inscriptions) shows how highly
energetic causes can generate energetically minor effects. Nor is it
clear what it means for some causal contributor to development to
count as an information-bearer, rather than some other kind of
developmental participant, such as an information-reader, or a
background condition for information transfer (Oyama 1985 [2000];
Griffiths 2001).



Seen in a more positive light, the plasticity of the term supports a
wide range of stipulative definitions of information (Lewens 2015).
These in turn facilitate an eclectic use of models and explanatory
tools. Framing cultural evolution in informational terms might also
support further borrowing from the theoretical study of biology. For
example, what are known are "major evolutionary
transitions" are sometimes characterized in terms of significant
changes to the way inherited information is stored, transmitted or
interpreted. In their pioneering discussion of these transitions,
Maynard Smith and Szathmary give examples including the initial
arrival of the genetic code, the advent of sexual reproduction, and
epigenetic inheritance. They also cite the development of language as
a further example of an informational transition, illustrating the
potential for an informational account of culture itself to integrate
with broader discussion in theoretical biology (Maynard Smith &
Szathmary 1995; Jablonka & Lamb 2006; Calcott &
Sterelny 2011)--a potential that is beginning to be actualized
(e.g., Waring & Wood 2021).


### 2.2 Transmission and Inheritance



There are two major approaches to marking out the distinctive nature
of cultural transmission and inheritance. The first looks at important
aspects of the *content* of information; the second, the
relevant *channel* of transmission mechanisms.



As an example of the first approach, consider Jablonka and Lamb
(2005). They claim that only some forms of social transmission make
use of a system of *symbols*. While it is true, for instance,
that some birds inherit their song by social transmission, this does
not imply that birdsong is a symbolic system. Humans, by contrast,
trade in publicly-accessible symbols.



This approach allows for further distinctions among types of symbol
system that make them more or less amenable to change. In some cases,
the relationship between a symbol and what is represented is
arbitrary. This the case for a word like "airplane", which
does not look or sound like a plane. This arbitrariness can facilitate
rapid change in the scripts or sounds used to denote a plane (Kelly et
al. 2021). In cases of *iconic* symbolism, the relationship is
one of resemblance: signs for the airport do look like a plane. These
may be less likely to change (Miton & Morin 2021).



Jablonka and Lamb use the characteristic differences between typical
modes of social inheritance in animals and humans to illuminate the
impact symbolic transmission systems have on human cultural evolution
(see also: Deacon 1997). Although they argue that there can be
non-linguistic symbolic systems (Jablonka & Lamb 2005: 224),
language exemplifies nicely the way in which systems of symbols
contain elements that can be recombined in countless ways to yield a
vast array of different meaningful messages. Furthermore, repositories
of symbolically stored information, such as books, computer databases,
and libraries can also be searched, annotated, edited and so forth, in
ways that add to their power and versatility. Such repositories can be
powerful means by which knowledge accumulates across generations.



This manner of thinking opens several challenging issues. One
important issue is the degree to which symbolic systems resemble other
inheritance systems. Consider, by way of example, Stegmann's
(2004) discussion of the sense in which the genetic code is
"arbitrary". One quickly realizes that attempts to specify
what makes some inheritance system a symbolic system, and to
differentiate between types of symbolic systems (linguistic,
non-linguistic and so forth) is philosophically demanding.



A contrasting approach aims at distinguishing cultural inheritance and
transmission by focusing on a distinctive *channel* by which
information moves. Typically, this identifies cultural inheritance
with information carried by mechanisms of social learning, as opposed
to genetically transmitted information, or information transmitted via
other "channels" (Boyd & Richerson 1985; Richerson
& Boyd 2005). Yet what is social learning?



In an important overview of work on cultural evolution, Henrich
defines this key notion alongside the notion of "individual
learning" that it is regularly contrasted with:



> 
> 
> ... social learning refers to any time an individual's
> learning is influenced by others, and it includes many different kinds
> of psychological processes. Individual learning refers to situations
> in which individuals learn by observing or interacting directly with
> their environment (Henrich 2016: 12)
> 
> 
> 



One consequence of this definition (a consequence which Henrich
explicitly recognizes) is that "social learning" and
"individual learning" are not exclusive. In our species it
is rarely the case that what an individual learns is free from
influence by others. Even in extreme cases, where we learn by probing
our surroundings well away from social company, almost every aspect of
the environments we interact with--and hence what we end up
learning from those environments--has been affected by other
people's past actions. The structures and contents of our
dwellings and workplaces, the constitutions of the domesticated plants
and animals we interact with, the cultivated and engineered
environments we live in, all have been affected by the activities of
our predecessors.



Yet as the distinction between social and individual learning blurs,
the question of whether there is a distinctive culture channel becomes
less clear (Lewens 2017). For there are numerous ways in which
activities of one generation can, by altering or maintaining stable
features of biotic, social, and technical environments, have an
influence over what individuals in the following generations end up
learning (Laland, Odling-Smee, & Feldman 2000).



In response to these concerns, researchers have been motivated to find
further distinguishing characteristics of sub-varieties of social
learning. Henrich, for instance holds that



> 
> 
> ...the least sophisticated forms of social learning occur simply
> as a by-product of being around others, and engaging in individual
> learning.
> 
> 
> 



He reserves the term "cultural learning" for the



> 
> 
> more sophisticated subclass of social learning abilities in which
> individuals seek to acquire information from others. (2016:
> 12-13)
> 
> 
> 



Critics of these final comments (e.g., Clarke & Heyes 2017; Heyes
2018) have urged further research concerning whether individual
learning--which, as we have seen, can take place in felicitously
structured environments--truly is less sophisticated than forms
of learning directed to the behaviors of others. They encourage us to
question whether there is an additional form of complexity in the
cognitive mechanisms that underpin social (compared with individual)
learning, and whether social learning has greater functionality with
respect to the generation of increasingly refined behaviors,
technologies, norms and institutions across populations.


### 2.3 Reproduction and Selection



While there may be a rough consensus among cultural evolutionists on
the informational character of culture--perhaps even the social
nature of transmission--there is less consensus on the nature of
selection or reproduction in the domain of culture.



Here, skeptical arguments have set the stage. Fracchia and Lewontin
(1999: 72-78), for instance, claim there are no analogs to
biological reproduction and natural selection in cultural evolution.
They take this to seriously undermine the predictive and explanatory
power of the analogy. Worse, they say that attempts to fit culture
into an evolutionary scheme are procrustean, lopping off the social
power relations and "sociocultural particularity" they
take to be at the core of explaining cultural change. Fracchia and
Lewontin argue instead for understanding cultural change as an
inherently historical process, where explanations appeal to the
particular cultural histories of groups (an approach very similar to
Sahlins's [1985]).



In response, cultural evolutionary researchers have offered a nested
taxonomy of explanatory frameworks that researchers might apply to
understand culture, whose categories reflect increasingly close
applications of the analogy between biology and culture. The hope is
to confine concerns like Fracchia and Lewontin's to the most stringent
set of approaches, freeing up more liberal interpretations as the
basis for empirical work.



Claidiere, Scott-Phillips, and Sperber (2014) for instance,
distinguish between *populational, evolutionary, selectional,*
and *replicator* frameworks for explaining cultural change.
Roughly, populational frames provide explanations in terms of the
frequency of types that change over time. These could be token ideas,
artifacts, or behaviors understood as instances of cultural
"traits". Evolutionary approaches are a sub-variety of
populational approaches: they assume that distributions of cultural
traits in a population can be explained by appeal to properties of
distributions at an immediately earlier time. Selectional approaches
are a sub-variety of evolutionary approach, which appeal to a form of
cultural natural selection to explain changes in frequencies of
cultural traits. Finally, replicator approaches are a sub-variety of
selectional approaches. They assume that cultural evolution acts on
cultural "replicators", where cultural replication is
understood in a fairly demanding way. To illustrate the difference
between some of these approaches, consider that a *selectional*
approach to the technological evolution of tools, for example,
requires comparatively little. There must be variation and inherited
resemblance over time, with some types of tool increasing their
frequency over others in virtue of better fittedness to local demands.
A *replicator* approach adds the further requirement that these
tools, or perhaps the ideas that give rise to them, make copies of
themselves in ways that closely parallel genetic replication.



Aside from *memeticists* (discussed in more detail below), few
cultural evolutionary researchers are committed to the widespread
existence of cultural replicators. Instead, contemporary work in
cultural evolution largely adopts a populational framework. But this
framework encompasses many possible approaches. Perhaps the prevailing
approach to "population thinking", exemplified by many
classic studies in the literature (e.g., Cavalli-Sforza & Feldman
1981; Boyd & Richerson 1985), denotes any effort that employs
abstracted psychological profiles to explore the consequences of
individual-level learning dispositions for the population-level
properties of groups. We will see several examples of such thinking
below in the section on "dual-inheritance". The
establishment of population-level consequences are important, for they
enable investigators to revise the constraints one might naively think
must bear on cultural inheritance if specific forms of cultural change
are to occur.



To others, the lack--or sheer implausibility--of strict
selectional or replicator frameworks have spurred exploration of
mechanisms *similar to*, but not identical with, the natural
selection schema. For instance, Strimling, Enquist, and Eriksson
(2009) develop a model that appeals not just to differential
representation--that is, of traits in the minds of
agents--but also to differential *persistence* in the face
of new learning. Think of recipes. Home chefs will have learned how to
cook many recipes over the years. Many will be too fussy, too complex,
or too bland to warrant making more than once or twice. But some will
be winners. These will be recipes cooked time and time again. Though
the home chef will have learned how to cook all these recipes, both
the overwrought and the tried-and-true, only the latter
*stick,* in the sense they are employed again and again. The
addition of such "stickiness" to a mechanism of selection
makes it disanalogous to the natural selection schema, but perhaps not
in a way that complicates the applicability of a more general
evolutionary schema nor nearby notions like fitness (Ramsey & De
Block 2017).



Similarly, many have noted the disanalogies between social
transmission and biological reproduction. Only the former involves
agents that recognize, reconstruct, and transmit traits if and when
they so choose (Cao 2020). To others, these disanalogies are just a
problem of locating the relevant spatiotemporal grain at which
*as-if* reproductive relationships can be identified (e.g.,
Acerbi & Mesoudi 2015).



To extract a general thread winding through this section, attempts to
"save the phenomena" appear to limit the explanatory power
of selective explanations. For if selection and reproduction rely on
agential dispositions to recognize, reconstruct, retain, and express
cultural traits--and if these dispositions strongly depend on
cultural history and context--then selective explanations do not
seem an advance on already operative social scientific methods (Sober
1991). Consider that cultural selection should be able to explain the
striking fit between cultural traits, the technologies of particular
groups, and the local ecologies in which they operate. But the extent
to which selective explanations are more illuminating than historical
or agent-centered explanations is far from clear (Chellappoo 2022). We
return to this point below.


## 3. A Strong Analogy: Memes and Memetics



Consider again the theory of memetics. This theory, originally put
forward by Richard Dawkins (1976), is perhaps the best-known attempt
to apply evolutionary thinking to culture. That said, while it has
enjoyed considerable popular attention, it has not become
well-established in scientific circles (although see Shennan 2008,
2011 for significant work that takes the meme's-eye view).



The meme theory draws a strong analogy between evolution at the
cultural level, and biological evolution. It begins with an abstract
characterization of selection as a process requiring entities that
reproduce, such that parents resemble offspring. It moves on to take
the more demanding view, popularized by Dawkins, that entities which
have the ability to make faithful copies of themselves--so-called
"replicators"--are required to explain this
trans-generational resemblance. In standard biological models of
evolution, it is assumed that genes are the relevant replicators.
Genes make copies of themselves, and this ability explains why
offspring organisms resemble their parents. If culture is to evolve,
it therefore becomes necessary to find some cultural replicator that
explains cultural inheritance. Memes play this role. Dawkins gives a
list of some exemplary memes: "tunes, ideas, catch-phrases,
clothes fashions, ways of making pots or of building arches".
Note that while it is sometimes assumed that all memes are ideas (and
vice versa), Dawkins's list includes other types of thing, such
as ways of making pots, which are techniques (see the entry on
 replication and reproduction).



Dawkins's claim is that ideas, for example, can be
conceptualized as entities that hop from mind to mind, making copies
of themselves as they go. On the face of things, this seems an
attractive proposition. Just as genes make copies of themselves at
different rates according to their effects on the organisms that bear
them and on their local environments, so ideas make copies of
themselves at different rates according to their effects on the
organisms that bear them and on their local environments. In a
community of scientists, for example, different hypotheses are
entertained, and some come to be believed more widely than others. A
hypothesis that begins in the mind of one or two scientists thereby
spreads, until it is widely held in the research community. Another
hypothesis quickly dies.



We can perhaps characterize the features that make some hypotheses
likely to spread, and others likely to perish. "Fit"
hypotheses may have predictive power, or simplicity, or they may
integrate well with existing bodies of theory. Note that what this
example shows is that taking the meme's-eye perspective does not
literally show that we are being manipulated by selfish cultural
replicators. One can describe scientific change as a struggle between
selfish memes, but one can also describe just the same process in
terms of scientists choosing to accept, or to reject, theories by
reference to familiar criteria of explanatory power, theoretical
elegance and so forth. It is only an incidental feature of the
metaphor of memetic selfishness that appears to deprive humans of
control over which ideas they do, and do not, accept.


## 4. Problems with Memes and Memetics


### 4.1 Are Cultural Units Replicators?



Replicators are units that make high-fidelity copies of themselves.
Critics of the meme concept, however, argue that there are no
mechanisms that explain how memes are replicated in this fashion
(Sperber 2000; Claidiere & Sperber 2007). Though imitation
has often been suggested as a plausible mechanism, there are good
reasons to think that imitation may be too error-prone to underpin
replication. If we make a Victoria sponge cake using a secret family
recipe, you eat the cake, and then attempt to make another one, then
the chances are that the recipe you hit upon will not, in fact, be
exactly the same as the one we used, even if you are able to make a
similar-tasting cake.



Another significant worry for memetics is that when the same ideas do
spread through a population, it is rarely because they are literally
copied from each other. One alternative, for example, explains the
recurrence of traits via recognition and recall (Buskell & Tennie
forthcoming). Returning to the cake example; perhaps you eat a slice
of our Victoria sponge, you like it, and you decide to make one for
yourself. Perhaps the recipe you use is very similar to ours. But you
have not figured out by tasting our cake which ingredients needed to
go in and in what order. Rather, you *already knew* how to make
a Victoria sponge. Eating our cake simply triggered the use of a
recipe that was already in your repertoire. In this case, the cake we
produced led to you to produce a similar one; but not because your
recipe is a copy of mine.



A related form of explanation draws on Sperber's (1996, 2000)
claim that cultural trait recurrence makes use of what he calls
"attractors". In paradigm cases, these are culturally
shared patterns of thought, which enable representations to spread
through a population without literal copying. How does this work? The
idea is that much learning is in fact reconstructive, where agents
must infer and reconstruct the underlying form and content of a trait
from observable instances or traces (Buskell 2017b). These
reconstructions are biased due to shared patterns of thought, leading
to systematic transformations of the form and content towards more
attractive states. So, for example, if we have solid background
experience in cooking Indian dishes, we may be able to recreate a
newly encountered dal in such a way that my dal closely resembles the
one just tasted. But that might not be because we see the recipe and
copy it. It might not even be because we pay close attention to the
specific elements of the dal just tried and aim at re-creating its
component elements bit-by-bit. And it might not be because we already
have the specific recipe in our repertoire. Instead, the fact that we
are familiar with the traditions of cooking this type of food--we
already know the sorts of ingredients used, the basic palette of
methods and so forth--mean that with just a brief taste we are
already primed to make something similar.



Error-prone imitation and non-replicative trait recurrence (like
reconstructive learning) raise serious problems for the generality of
memetics: not all cultural traits are replicators, hence not all
cultural traits are memes. Defenders of the meme concept have offered
two different responses to this challenge.



The first is to make the conditions required for meme-hood less
demanding. Dennett (2017: 206), for example, seems to follow this path
when he argues that memes constitute "ways: ways of doing
something, or making something", which are transmitted
perceptually (rather than genetically). For Dennett, the meme concept
has pragmatic payoff because it draws attention to the existence of
stable re-tokenings of these cultural "ways", in a manner
that allows for cumulative forms of evolution via natural selection.
As we read him, this means that while Dennett does require a certain
level of fidelity in terms of resemblance of cultural tokens through
transmission processes, he does not require a process of replication
in the strict sense for an entity to count as a meme. Faithful
resemblance is enough, even when underpinned by processes of
Sperberian "attraction".



The second response, also suggested by Dennett (2017) as well as by
Cao (2020) among others, acknowledges that Sperberian arguments
establish that not all instances of cultural recurrence are instances
of cultural replication. Hence not all cultural traits--even when
reproduced faithfully--are memes. Even so, this leaves open the
possibility that some--perhaps many--cultural traits are
memes. What is more, it invites the investigator to examine whether
there are distinctive differences in cultural evolutionary dynamics
afforded by memetic and non-memetic cultural reproduction. Whether
this shows the meme concept to be useful depends on the sort of
insights to be had by distinguishing cultural inheritance that is
meme-like from cultural inheritance that is not (Sterelny 2006a).


### 4.2. Do Cultural Units Form Lineages?



A second important line of critique draws on the fact that while in
genetic replication one can trace a new copy of a gene back to a
single parent, ideas are rarely copied from a single source in a way
that allows us to trace clear lineages (Boyd & Richerson 2000;
Godfrey-Smith 2012).



Memeticists are fond of analyzing religious belief in terms of the
spread of memes. But while religious beliefs may well spread through
populations of humans, it seems unlikely that we will always be able
to trace token instances of faith back to one source. Instead,
individuals often acquire belief in a God through exposure to several
believers in their local community. In these circumstances, belief in
a God is not caused by one identifiable earlier token of the same
type.



This poses a problem for meme theories, because in biological
evolution Mendel's laws have been important for explaining some
aspects of evolutionary dynamics. Mendel's laws rely on an
understanding of genes as discrete, transmitted units. But if token
ideas can appear in an individual in virtue of that individual's
exposure to several sources, then this makes it unlikely that anything
close to Mendel's laws will be discovered within cultural
evolution. This suggests a practical limitation on inquiry that may
result from this difference between ideas and genes.



Criticisms of this form have been forcefully put forward by William
Wimsatt (1999). He argues that the creative and inferential abilities
of human users make it the case that any given idea, or item of
technology, can have fluctuating numbers of cultural parents over
time. This is because the causal sources of its reproduction may vary.
Belief in a God may sometimes be caused by exposure to a single
charismatic evangelist, sometimes by the joint inculcation of two
biological parents, and sometimes by immersion in a diffuse community
of theists. There are no hard and fast rules of cultural
inheritance.



Ideas and items of technology also have no stable analogue to the
genome, or germline, because different elements within cycles of
technological reproduction, including ideas, behaviours of artisans,
and material elements of technologies themselves, can all temporarily
acquire the status of replicators depending on the attention that
human agents happen to be paying to them. Accidental variations in
one's mental plan for constructing a pot, in actions producing
the pot, or in the finished pot itself, can all conceivably be
reproduced when another artisan comes to make a resembling item.
Wimsatt uses these disanalogies to highlight the formidable problems
facing any effort to use population genetic models in the explanation
of cultural change.


### 4.3 Can culture be atomized into discrete units?



Ideas stand in logical relations to each other. Whether an individual
can acquire some belief thus depends on conceptual competencies. It is
impossible to believe in the theory of relativity without
understanding it, and one cannot understand it without holding many
additional beliefs relating to physics. The same is true for
non-technical beliefs. Depending on which religion one is talking
about, belief in God is likely to be related to various other beliefs
concerning forgiveness, retribution, love and so forth.



There are two problems here. The first is whether, and to what extent,
culture can be decomposed into traits *at all*, and if so, how.
Cao (2020) argues that cultural traits should mostly be individuated
relative to the interests and capacities of the agents learning and
passing them along. Though this does provide a route towards
individuating and distinguishing cultural traits, it should be cold
comfort to memeticists. Recall that for memeticists, memes are
individuated independently of the interest of agents, who are supposed
to be mere hosts or scaffolds for the reproduction of further
memes.



The second problem concerns the extent to which *replication*
operates over discrete traits, however individuated. The
anthropologist Adam Kuper, for instance, complains that



> 
> 
> Unlike genes, cultural traits are not particulate. An idea about God
> cannot be separated from other ideas with which it is indissolubly
> linked in a particular religion. (Kuper 2000: 180)
> 
> 
> 



Memeticists are likely to respond by saying that although ideas are
interlinked, this does not undermine the meme-gene analogy.
O'Brien et al. (2010), for instance, have argued that a more
mature view of the role of genes in evolution and development
reinstates the meme-gene parallel. Genes, too, need to be studied in a
context that takes other genes, and their broader developmental and
environmental settings, into account. A DNA sequence can have
different effects in different organisms, depending on the network of
relations it enters into with other genetic and developmental
resources. Just as the significance of belief in God can vary with
social context, with the result that it can make little sense to think
of "belief in God" in general as a single type of meme, so
the function of some DNA sequence can vary with organic context, with
the result that it makes little sense to identify some sequence type
as a gene for the purposes of evolutionary analysis.



## 5. Looser Analogies


### 5.1 Dual-Inheritance Theory



The most sustained and respected approach to applying evolutionary
thinking to culture begins from a different starting point than
memetics. This alternative view starts from the observation that
cultural inheritance is important, and it seeks to integrate cultural
inheritance into traditional evolutionary models. If the memetic
framework tends to be driven by cultural analogies to genetic
evolution, *dual inheritance* models are driven instead by a
desire to find ways of understanding how cultural inheritance affects
evolutionary processes (Henrich & McElreath 2003). This approach
need not assume that cultural inheritance works in the same way as
genetic inheritance (see the entry on
 inheritance systems).



Researchers working in this tradition model cultural inheritance in
ways that frequently depart from genetic inheritance: they may build
in error-prone learning (e.g., Henrich 2001), acknowledge multiple
cultural "parents" (e.g., Enquist et al. 2010), or
emphasize the sequential (rather than all-at-once) acquisition of
cultural traits (Buskell, Enquist, & Jansson 2019). Nonetheless,
these models remain recognizably evolutionary in style, primarily
because they seek to explain changes in populational trait frequencies
over time. They do this by using broad assumptions about how
individuals acquire cultural traits, and by assessing how these
acquisition rules play out at the population-level. Moreover, these
rules are not merely conjectured: they are given experimental backing.
Dual-inheritance theorists document the effects of various
empirically-supported forms of bias, such as prestige bias. Just as
Darwin's own theory of evolution by natural selection remained
largely conjectural until supplemented by empirical work showing how
inheritance worked--and by statistical work focusing on the
population-level consequences of inheritance, selection, mutation and
other forces--dual-inheritance theory has gained insights from a
similar combination of empirical and mathematical approaches (e.g.,
Richerson & Boyd 2005; Jordan 2015; Henrich 2016).



Models in the dual-inheritance tradition sometimes aim at showing how
cultural change of various sorts--and not necessarily adaptive
cultural change--can affect genetic evolution, and vice versa.
These are models of gene-culture co-evolution. Other dual-inheritance
models aim at assessing the cultural evolution of adaptations. In the
latter set of models, theorists are not merely seeking to explain
*distributions* of traits in populations, they are also seeking
to explain the *origin* of valuable cultural novelties
(Godfrey-Smith 2012).



In section 4 we argued that cultural change does not require cultural
replicators. Various strands of work indicate that this is true even
when cultural change is adaptive. The general Darwinian scheme for
explaining adaptation demands reliable inheritance--that once a
fitness-augmenting mutation arises, it can be retained in future
generations. If cultural learning is error-prone, or if individuals
acquire cultural traits by taking an average of many different models,
then one might think that even if some individual were able to
discover a fitness-enhancing behavior, that trait will be lost to
future generations either because it might be miscopied or because it
might be combined with less adaptive traits to produce an averaged
mish-mash of a behavior. These considerations in favor of the
importance of replication have all been challenged by recent cultural
evolutionary theory.



Cultural evolutionists agree that, at the level of the population,
cumulative evolution requires that fitness-enhancing cultural traits
are preserved in the offspring generation. However, they deny that
this requires faithful transmission between individuals. A formal
model from Henrich and Boyd (1998) suggests that conformist
bias--defined as the exaggerated tendency of individuals to adopt
the most common representation in a population--can overcome the
effects of error-prone learning to produce reliable inheritance at the
population level. Henrich and Boyd's theoretical model assumes
that individuals are poor at inferring the representations of others.
Even so, when one looks to the population level, conformist bias helps
to correct the effects of such errors, by producing a population-wide
distribution of representations in the offspring generation that is
close to the population-wide distribution of representations in the
parent generation. Henrich and Boyd explain the reason for this: in
general, error-prone transmission tends to produce a mixture of
different representations. In a population that already contains
several different representations at significant frequencies, the
effect of error on a population-wide distribution of representations
is therefore low. In a population in which one representation is
common, the effects of error are much more significant. But if we add
conformist bias--and perhaps other biases, like prestige
bias--we increase the chances of a commonly held representation
remaining commonly held in future generations, even with error-prone
imitation.



Boyd and Henrich acknowledge that this mechanism does not ensure
population-level distributions are perfectly reliably inherited. But
this does not mean that cumulative evolution acting on cultural
inheritance is impossible. At the genetic level, highly faithful
copying processes allow even very small selective forces to preserve
adaptive variation. Less faithful copying demands stronger selective
forces if adaptive variation is not to be lost (Enquist et al. 2010).
Boyd and Henrich are confident that selective forces in the cultural
realm are stronger than selective forces in the genetic realm. The
moral, once again, is that it is important not to focus too closely on
genetic evolution as a model for cultural evolution (Sterelny 2012;
2021b).


### 5.2. Cultural Attraction



Sperber, and other advocates of the approach to cultural evolution
known as "cultural epidemiology", or "cultural
attraction theory", share with dual-inheritance theorists a
populational approach to cultural evolution:



> 
> 
> the overall general framework for the study and modelling of cultural
> evolution should be that of "population thinking"
> .... (Claidiere, Scott-Phillips, & Sperber 2014)
> 
> 
> 



Their distinctive contribution lies in the claim that any successful
execution of this approach requires that explanations of the
distribution of cultural items pay close attention to what they call
cultural "attractors" (Sperber 1996). Moreover, they argue
that this approach frequently (although not always) gives rise to
explanations that elude approaches grounded in forms of cultural
selection.



As indicated earlier, Sperber argues that the simple notion of copying
is only rarely appropriate to explain why broadly similar cultural
items propagate in a stable manner through a population. For example,
when emotional states spread through communities--perhaps at
times of national mourning--one individual's expression of
grief can be causally initiated by another's. But the second
individual does not closely imitate, or copy, the emotional state of
the first, even if the second emotional state resembles--and
hence is a "reproduction" of--the first. Instead, a
shared set of emotional dispositions, perhaps coupled to shared norms
for public behavior, conspire to reconstruct a similar emotional
state. Such recurrent states, which are the broadly stable outcomes of
these reconstructive processes, are examples of cultural
"attractors".



We gave a rough gloss on attractors above. It is worth underlining the
point, however, that an attractor should not be equated with the
psychological attractiveness of some trait to individuals (Sperber
1996; Buskell 2017a). Instead, an attractor is a more abstract notion
corresponding to the more-or-less stable outcome of processes of
cultural reproduction. And very many different "factors of
attraction" can potentially underpin such stable reproduction.
For example, if a widely encountered engineering problem has only a
few effective solutions, and these are also easy to figure out, then
one should expect those solutions to appear again and again, even if
individuals are not attempting to copy the innovations of others in
detail. Thus, factors of attraction need not be psychological at all;
they may be constellations of physical, ecological, and even
informational constraints (Falandays & Smaldino 2022). Shared
bodies of information, shared preferences, and shared emotional or
inferential biases might also explain why some cultural variants
reappear with regularity.



Some attractors may be grounded in evolved and universally held
cognitive dispositions. Indeed, Sperber and like-minded colleagues
have often declared explicit debts to evolutionary psychology (Sperber
1996). Yet cognitive attractors may also be local, corresponding to
more narrowly shared dispositions or biases held by communities. Such
dispositions can explain reproduction that is only reliable across
narrowly specified cultural contexts. Work along these lines aims at
answering the charge that the cultural epidemiology approach is
vacuous or not action-guiding for empirical work (e.g., Buskell 2019).
It does so by attempting to outline factors of attraction, and their
populational consequences, at various spatial and temporal scales
(Morin 2011 [2016a]).


### 5.3 Cultural Systems



A more recent approach within the cultural evolutionary research
community--albeit one with a lengthy pedigree outside that
domain--examines cultural change through the lens of systems
thinking (Buskell, Enquist, & Jansson 2019; Jansson et al. 2021).
This approach starts from an observation that there is a difference in
how cultural traits (in individuals and in groups) are acquired as
compared with biological traits: while the latter are largely
inherited all at once (in a sexual species, at the moment of
fertilization, say), cultural traits can be acquired over a protracted
period of time. The sequential acquisition of cultural traits means
those acquired earlier in time can affect the acquisition of those
encountered later.



Acerbi, Enquist, and Ghirlanda (2009) illustrate the general idea of
the cultural systems approach with a model that explores the
transmission of traits that make individuals either "open"
or "conservative"--that is, open to acquiring new
traits, or happy to sit tight. As they suggest, a trait making one
"conservative" could spread to "open"
individuals--but the converse is not the case. Once an agent
acquires the "conservative" trait, no new learning will
occur. Expanding this line of thought, Jansson et al. (2021) argue for
the importance of cultural filters: collections of traits that
regulate the attentiveness towards, evaluation of, and potential
acceptance of novel traits. The general idea is that relations of
compatibility holding between already acquired traits will influence
the addition of new ones. Thus, idiosyncratic collections of traits
and their respective compatibility profiles--themselves the
result of the sequential acquisition of traits--will modulate
downstream acquisition.



The systems approach is less overtly evolutionary than either
dual-inheritance theory or cultural epidemiology. Proponents argue
that a systems approach provides a framework well-suited for
formalizing and exploring the population level consequences of claims
made about culture in the humanities and social sciences. Yet given
the approach's similarity to longstanding network approaches in
quantitative sociology (e.g., Axelrod 1997; Centola 2015; Goldberg
& Stein 2018), one might rightly wonder--at this point, what
remains of the analogy between biology and culture?


### 5.4 A Persisting Problem: The Explanatory Power of the Biology/Culture Analogy



At the beginning of this entry it was claimed that the case for
cultural evolution was irresistible. No one can deny that cultural
inheritance is an important factor in explaining how our species has
changed over time. In spite of all this, one might still worry that it
is a mistake to understand the importance of culture using the tools
of evolutionary theory. This is because one may be skeptical of the
existence of a theory that is both general enough to cover all forms
of cultural change and informative enough to be enlightening.



There is no doubt that it is often important to remind
overly-enthusiastic orthodox Darwinians of the importance of culture.
For example, it seems that the increased incidence of
lactose-tolerance among human populations has arisen as a consequence
of a cultural innovation--namely dairy farming. The relatively
recent appearance of this genetically-controlled adaptation
demonstrates that human physiological nature is something that
continues to change, and it also demonstrates the causal impact of
culture on genes (Richerson & Boyd 2005: 191-92). Such
examples by themselves show the rashness of any view that claims
either that human nature has remained fixed since the Stone Age, or
that genes are somehow in the evolutionary driving seat. Yet none of
this shows that we can develop a general, informative theory of
cultural evolution. One might fear that, in the end, the influence of
culture on aspects of the human species is best understood through a
series of more idiosyncratic narratives.



Our brief examination of memetics illustrated this concern. We gain no
real explanatory insight if we are told that ideas spread through
populations, some more successfully than others. We want to know what
makes some ideas fitter than others. And it is not clear that there
will be any general rules that can help us to answer this question. In
the biological realm, we need detailed accounts of local environmental
circumstances, species-specific physiology and anatomy, and so forth,
to tell us what makes one organic variant fitter than another.
Similarly, in the cultural realm we need to look at local
psychological dispositions to explain why some ideas are more likely
to spread than others. Thus any explanatory value to be had from
cultural evolution may be parasitic on conventional work done in
psychology. And if individual preferences are subject to change over
time, then there may be no general and informative theory of cultural
evolution to be had; rather, we will have to settle for local
explanations that look to shifting preferences. Rather than provide a
new scientific framework for an understanding of culture, cultural
evolution will tend to degenerate into conventional narrative cultural
history (Fracchia & Lewontin 1999).



In a useful article, Elliott Sober (1991) suggests that theories of
cultural evolution may have limited value for the work of social
scientists, on the grounds that social scientists are primarily
interested in explaining what makes individuals likely to adopt one
idea, rather than another. Perhaps culture is composed of replicating
entities struggling against various selection pressures, but what
insight does this offer us, if in the end it presents us with nothing
more than an alternative idiom in which to describe the various
factors that affect the evaluation of culture? Perhaps clothes
fashions are memes, but even if that is the case, one still needs to
explain what makes one clothing meme fitter than another, and the fear
is that once spelled out this will quickly boil down to a well-known
appeal to consumer psychology.



Once again, Dennett (2017) has offered a response on behalf of the
memetic approach, but it serves as a potential response from cultural
evolutionary theorists more broadly. He draws attention to the risks
of assuming an overly rational perspective on the factors influencing
the uptake of cultural traits: one should not assume that ideas are
widely adopted because they are understood and explicitly endorsed by
those who adopt them; one should not assume that technological
innovation occurs because users or designers understand the nature of
the contribution made by some novel variant. If, as Darwin argued, the
selection, preservation and augmentation of organic variation (in the
early stages of domestication, for example) can sometimes be
unconscious, it follows that the selection, preservation and
augmentation of cultural variation can sometimes be unconscious,
too.



Richerson and Boyd respond in a different, albeit complementary way.
They say that Sober's argument assumes, erroneously, that
"we are all good intuitive population thinkers" (Richerson
& Boyd 2005: 97). In Sober's original article he points out
that population thinking might save cultural evolutionary models from
vacuity in just this way:



> 
> 
> So the question about the usefulness of these models of cultural
> evolution to the day-to-day research of social scientists comes to
> this: Are social scientists good at intuitive population thinking? If
> they are, then their explanations will not be undermined by precise
> models of cultural evolution. If they are not, then social scientists
> should correct their explanations (and the intuitions on which they
> rely) by studying these models. (Sober 1991: 492)
> 
> 
> 


## 6. Extensions and Elaborations


### 6.1 Coevolution and the Cultural Evolution of Cultural Evolution



Perhaps the core assumption of all approaches to cultural evolution is
the thought that rampant social learning is an important explanatory
process. Yet one may reasonably ask why it should be the case that we
have the ability to learn from others at all, given the adaptive costs
of such a disposition.



Boyd and Richerson (1985) claim that the overall adaptive benefits of
learning from non-parents outweigh the costs (Richerson & Boyd
2005: Ch. 4). They give several reasons for this view. Suppose an
inventive (or lucky) individual discovers some behavior, or technique,
which augments fitness. If other individuals in the population can
copy that behavior, then their fitness will probably be augmented,
too. It will often be difficult for individuals to ascertain which
behaviors in fact augment fitness, hence which behaviors should be
copied. The problem, then, is how to tune a learning mechanism so that
beneficial behaviors are copied, while non-beneficial behaviors are
not.



Boyd and Richerson suggest that *prestige bias* can overcome
this problem: if individuals copy techniques from those who are in
prestigious positions, then this increases the chances that they will
copy techniques that are, in fact, beneficial. As they put it,
"Determining *who* is a success is much easier than
determining *how* to be a success" (Richerson & Boyd
2005: 124). Moreover, evidence has been accumulating for the reality
of prestige bias. Henrich and Broesch (2011) have argued, based on
fieldwork in Fiji, that an individual's perceived success in a
single domain of activity (for example, yam cultivation) predicts
whether that individual will be asked for advice in other domains (for
example, fishing). In other words, they claim that individuals are
accorded a broad form of prestige, which affects their likelihood of
serving as a cultural model. The value of prestige bias relies on the
supposition that those individuals who are able to get themselves into
prestigious positions have a better than average tendency to make use
of fitness-enhancing techniques.



Richerson and Boyd (2005: 120-22) suggest other learning
heuristics may be adaptive too. One we mentioned above is
*conformist bias*. To say that someone has conformist bias is
to say that the person in question tends to imitate those behaviors,
beliefs or other dispositions that are present among a high frequency
of individuals in the population. More precisely, this bias is usually
defined as a heightened, or exaggerated, tendency to imitate the most
common behavior. They argue (along with many others in the field) that
conformist learning provides an individual learner with behaviors that
are appropriate to novel situations. More specifically, they argue
that it is more adaptive in this regard than not imitating others at
all, and more adaptive than imitating randomly-chosen members of a
population. Conformist learning, they say, can help with the
acquisition of behaviors appropriate to a new biological environment:
when moving into a new habitat, with unknown plants and animals, it is
best to eat the foods the locals eat, for one thereby avoids
poisoning. But it can also lead to the generation of socially
appropriate behaviors, which will obviate ostracism or attack.
Supporting this idea, Harris and Corriveau's (2011) empirical
work concludes that while young children are unselective with regard
to what they learn, they are far more selective regarding whom they
learn from. Moreover, they argue that children tend to seek out
cultural conformists as individuals whom they should trust. These
findings offer some support for the existence of a form of conformist
bias, although Lewens (2015) has suggested that both the theoretical
and empirical cases for conformist bias may not be as strong as first
meets the eye, and Chellappoo (2021) has offered a similarly skeptical
evaluation of the case made for prestige bias.



Returning to the question that initiated this section--Why can we
learn from others at all, when what we learn often seems
detrimental?--these examples illustrate the form of
methodological adaptationism shared between much cultural evolutionary
thinking and the evolutionary psychological approach it is sometimes
contrasted with (Lewens 2015). Cultural evolutionists tend to argue
that while the *overall* adaptive benefits of social learning
dispositions in past environments explain their origination through
natural selection, this means neither that each specific learned trait
must lead to a fitness benefit, nor that the overall payoffs of
learning must still be positive in the context of modern informational
environments that differ radically compared with those that confronted
our ancestors.


### 6.2 Cumulative Culture



Other work done by cultural evolutionary researchers begins from
considerations of explanatory puzzles similar to those that led Darwin
to formulate his principle of natural selection in the first place.
Darwin was concerned to explain how structures could arise which fit
organisms so remarkably well to their conditions of existence.
Cultural evolutionists frequently draw attention to a variety of
adaptive cultural traits, whose origination seems inexplicable in
terms of individual innovation alone.



Henrich (2016: 97-100), for example, makes good use of the
example of manioc processing. Manioc (also called cassava) is a good
source of starch, but it needs to be processed to make it safe to eat.
Without this processing it can release poisonous hydrogen cyanide.
According to Henrich, while unprocessed manioc tastes bitter, the
bitter taste is not a good indicator of its safety: bitterness
disappears in the preparation process before manioc becomes safe to
eat. Worse, while unprocessed manioc is poisonous, it is hard to
discover that this is the case, because the symptoms of poisoning only
appear well after eating unsafe manioc. Henrich argues that it is hard
to see how any single insightful individual could have invented this
processing technology. Instead, he argues that a more gradual process
of cumulative cultural adaptation, spread across the
population--a form of "hidden hand explanation"
modeled on organic selection--must be invoked.



The prevailing metaphor used to describe this process of cumulative
cultural adaptation is that of a ratchet. Cultural traditions must be
built-upon--and must not "slip-back" over
time--if such adaptive traits are to be generated, maintained and
further elaborated (Tomasello, Kruger, & Ratner 1993; Tomasello
1999). In fact, such "incremental improvement" is taken to
be a "core criterion" of what is simply called
"cumulative culture" (Mesoudi & Thornton 2018).



Two features of this characterization of cumulative culture have
exercised commentators. The first is the "lumped"
character of the cumulative culture concept: the concept encompasses a
set of evolutionary patterns, processes, and products that might
better be kept distinct. Buskell (2022) for instance, suggests that
the underlying *process* of accumulation--the ratchet-like
retention of modifications made to traits over time--should be
distinguished from the cultural evolutionary *patterns* (or
"trends") typically associated with it; notably, the
complexity, adaptiveness, or efficacy typically associated with
cumulative culture. This preserves the "ratchet" of
modification and retention, but distinguishes it from
"incremental improvement", opening up the possibility of
generating both *maladaptive* and *neutral* traits. Just
as copying errors or mutation may lead to deleterious or neutral forms
of traits being passed on over time--so too might cumulative
culture.



A second set of concerns considers which features of cumulative
culture, if any, mark it out as a distinctive kind of cultural
evolutionary process. It is usual to express the ratcheting
requirement in terms of the need for high-fidelity in social learning.
This, in turn, is most obviously spelled out as a requirement for a
token of a trait in a learner to faithfully resemble the token of the
same trait in the model. But it is not clear what "grain"
of analysis should be chosen when determining resemblance (Charbonneau
2020; Charbonneau & Bourrat 2021). Suppose Andrew sings a line
from a song, and Tim attempts to copy him: does "high
fidelity" learning require Tim to reproduce the same melody,
must he sing in the same key, must he sing with the same words, and
the same emotional emphases? Note that this also raises the linked
question of what it takes for two tokens to be of the same trait type.
If Tim sings with different words and in a different key, are we
dealing with tokens of the same, or a different trait type? There is
plausibly value to the investigator in distinguishing different types
of modification, rather than using a single "hi-fi/lo-fi"
dimension. For example, one may wish to distinguish rearranging or
multiplying the elements involved in some complex behavior, from
altering the nature of those elements themselves (Charbonneau 2016;
Buskell 2020).



Last are concerns about identifying instances of cumulative culture.
Work in comparative cognition shows that culture is widespread among
non-human animals. Yet evidence for cumulative culture is contentious.
Tennie, Call, and Tomasello (2009: 2413) have argued that



> 
> 
> the cultural traditions of non-human primate species...do not
> seem to accumulate modifications over time with any kind of ratchet
> effect.
> 
> 
> 



Their view is that behavioral solutions in chimpanzees, for example,
are always drawn from a limited repertoire--what Tennie and
colleagues (2009) call a *zone of latent solutions
(ZLS)*--which contains only solutions that an individual
might potentially discover by itself. This does not mean that there is
no element of accumulation in primate culture: Tennie et al note that
an individual primate may be assisted in acquiring some behavior by
the performances of others, and by the use of discarded tools. There
is, then, scope for limited building on the achievements of earlier
individuals. Even so, they suggest the ZLS places strong limits on
cultural accumulation in these contexts. Regardless of whether the ZLS
approach is a good means of evaluating the cultural capacities of
animals, the prevalence of animal cultural traits and the evolutionary
role of cumulative culture have been hotly disputed (Schuppli &
van Schaik 2019; Haidle & Schaludt 2020; Sterelny 2021b). If
nothing else, this work suggests that identifying instances of
cumulative culture among non-human animals is a difficult empirical
issue.


### 6.3 Cultural Group Selection



Introductory textbook examples of natural selection typically use
cases where individual organisms differ with respect to how many
offspring they have, and adaptations that promote individual fitness
are selected as a consequence. For example, it is well-confirmed that
camouflage puts individual peppered moths at a selective advantage
over less-well camouflaged individuals in the face of predation by
birds. However, theorists have regularly suggested that groups of
organisms might also differ in their fitness, and that adaptations
promoting group fitness might be favored by the action of selection at
this higher level (see the entry on
 units and levels of selection).
 In mainstream evolutionary theory, progress has been made in
disambiguating what is meant by group fitness--it can mean either
the ability of a group to produce individual organisms, or the ability
of a group to produce new groups--and also in assessing how
robust the effects of group selection might be (Okasha 2006).



Several leading theorists of cultural evolution have placed
considerable stress on the importance of what they have called
Cultural Group Selection (sometimes abbreviated to "CGS").
CGS is a form of group-level selection that occurs when differences
between groups of individuals are maintained by cultural inheritance.
Darwin's own work on the emergence of human morality helps set
the scene for the sort of explanatory problem that a group selection
process (whether cultural or otherwise) is apt to solve. He points out
that forms of morally admirable behavior that benefit others can be
hard to explain using simple appeals to natural selection. In many
cases it seems an individual's ability to leave offspring will
be promoted by selfish, rather than other-regarding, actions. However,
the detrimental effects of selection at the level of individuals can
be overcome if selection is efficient at a higher level:



> 
> 
> When two tribes of primeval man, living in the same country, came into
> competition, if...the one tribe included a great number of
> courageous, sympathetic and faithful members, who were always ready to
> warn each other of danger, to aid and defend each other, this tribe
> would succeed better and conquer the other. (Darwin 1871: 162 [1877:
> 130], wording from the 1877 edition which is slightly different than
> the 1871 edition)
> 
> 
> 



Darwin writes of selection acting at the level of the
"tribe" or the "community". What makes the
appeal to higher-level selection salient is its potential ability to
override a countervailing force at the individual-level.
Individual-level selection promotes self-regard, says Darwin, but
competition between tribes favors other-regard (at least with respect
to other members of one's own tribe).



This feature is not always present in the recent invocations of CGS.
Consider how Heyes (2018) understands CGS. She notes that cultural
inheritance can often be "diffuse": a trait such as the
ability to ascertain what others are thinking and feeling
("mind-reading") is acquired in part by close interaction
with one's parents as a baby, also by interaction with other
relatives and siblings, by engagement with other children, and by
reflective exposure to sources such as novels and films under the
instruction of unrelated adults. In other words, these traits are
inherited via complex crisscrossing networks. Heyes conjectures that
this form of inheritance tends to reduce variation within groups,
thereby accentuating variation between groups, and establishing the
possibility of "an adaptive response at the level of the social
group" (2018: 41). In a more detailed presentation of her
understanding of cultural group selection, she envisages two groups
(for simplicity she calls them Right and Left). Each group has a
different prevalent version of some important cognitive mechanism.
Most people in Left have *M*, most people in Right have
*M*\*. *M* and *M*\* are stable features of Left
and Right respectively, because they are inherited via diffuse forms
of learning within those groups. If *M*\* better enables
individuals to carry out some significant function, then people in
Right may end up having more biological offspring than people in Left.
This means the Right group does better overall than Left and
*M*\* increases its representation in the population as a
whole.



We do not take issue here with the potential efficacy of the mechanism
Heyes proposes. We do, however, question whether it is a form of CGS.
Heyes thinks of this as CGS because one group is more successful than
the other, and because the inheritance of the traits of interest
(*M* and *M*\*) is achieved through forms of learning.
But this need not indicate a distinctively group-level process of
selection. This is the cultural analogue of an old-fashioned problem
in mainstream evolutionary theory. A herd of fast-running deer will do
better in terms of reproductive output than a herd of slow-running
deer, but it does not follow that this indicates selection at the
level of the herd. Here, the herd as a whole does better because of
the individual-level selection processes going on within it (Williams
1966).



Richerson and Boyd's "Tribal Social Instincts"
approach to CGS is much more closely aligned with Darwin's own
explanation of features of human moral psychology. Their favored
explanatory hypothesis is a complex one, involving interaction between
CGS and natural selection acting on genetic variation:



> 
> 
> Selection on tribes can account for the innate foundation of our
> social psychology via the process of gene-culture coevolution.
> (Richerson & Boyd 2005. See also: Boyd & Richerson 1985: Ch.
> 7)
> 
> 
> 



They argue, based on a mixture of historical, ethnographic and
theoretical work, for a scenario that begins with what they also call
"tribes"--they consider these to be ethnolinguistic
units of around 500 to 1500 people--competing against each other
in ways that are aided by culturally transmissible differences in
group properties. This competitive process eventually produces



> 
> 
> culturally transmitted cooperative, group-oriented norms, and systems
> of rewards and punishments to ensure that such norms are obeyed.
> (Richerson & Boyd 2005: 196)
> 
> 
> 



Once cultural transmission has established this social environment,
natural selection acting on genetic variation then favors an innate
psychology that is suited to this new, socially-inherited set of
environmental problems.



The Tribal Social Instincts hypothesis can be challenged on empirical
grounds: one can question the claims made about the innateness of the
social psychological dispositions in question, the characterization of
Pleistocene social groups and conditions, the inability of more
traditional evolutionary resources to explain our altruistic
tendencies, and so forth (see Birch 2017; Sterelny 2016, 2021b, 2022;
and Birch & Buskell 2022). Such challenges are inevitable when a
hypothesis is as ambitious as this one, and when it draws on such a
variety of supporting sources of data. There are also conceptual
concerns. The very idea of group selection has been a contested one
within mainstream evolutionary theory. Some commentators have taken a
skeptical view of group selection when underpinned by genetic
inheritance, because of worries that competition based on genetic
variation within groups will tend to undermine the effects of
competition between groups.



Several cultural evolutionists (e.g., Boyd & Richerson 2009;
Henrich 2016) reply that cultural inheritance processes are better
able than processes of genetic inheritance to sustain between-group
differences, for they believe there is good empirical and theoretical
evidence that cultural processes can maintain within-group homogeneity
in the face of various countervailing factors (immigration, unreliable
imitation and so forth). This leads to further questions concerning
how, in general, to characterize CGS. Richerson, Baldini, et al.
(2016) lists three different forms, of which straightforward
competition between groups is just one variant. The second, selective
imitation, happens when traits move from one group to another, when
individuals see their benefits and adopt them. The third, selective
migration, happens when individuals move from one group to another,
once again when they see the benefits of the traits in question. These
are indeed additional ways by which behavioral traits that are of
benefit to a group can increase in frequency in a larger population of
groups. However, in the second two cases, trait frequencies are
increased simply by individuals' attraction to traits that they
regard as bestowing collective benefits. Because two of these three
processes are quite different to what one might think of as a central
case of CGS--whereby groups compete against each
other--critics such as Morin (2016b) have argued that they are
not helpfully regarded as group selection processes at all.



Richerson and colleagues shrug off these concerns about labeling:



> 
> 
> The main thing all three have in common is that they are driven by
> variation among groups. We are not wedded to any particular
> terminology in this matter. (Richerson, Baldini, et al. 2016: SS
> R4)
> 
> 
> 



These issues need not be merely terminological, for (as we suggested
for Heyes's work) they also raise basic theoretical concerns
about distinguishing individual-level selection from group-level
selection. These concerns become especially acute in the context of a
species able to observe and learn from others. For suppose individuals
in group G1 slowly develop a process P1--perhaps a form of
processing food--that gives each individual using it an advantage
over the older technique P0. Within the neighboring group G2, everyone
still uses P0. Group G1 grows, flourishes, and expands its territory
thanks to P1. Soon individuals in G2 notice the conspicuous success of
the ever-expanding G1, they notice their neighbors in G1 are mainly
using P1, and they start to adopt P1 as a consequence. This is a
process whereby a group-beneficial trait spreads because of variation
between groups. It is also an instance of selective imitation. But at
least in this case--because of the payoffs of P1 compared with P0
for individuals--to call it an instance of group selection
threatens to introduce confusion in the context of more general
evolutionary theorizing. So selective imitation may sometimes be a
mechanism for a form of group selection proper, but it need not always
be.


### 6.4 Evolvability



Darwin's theory is intended to explain adaptation (see the entry
on
 adaptationism).
 The previous two sections have already touched on the general
conditions required for novel cultural adaptations to emerge over
time. In the organic realm, these conditions are sometimes understood
under the general heading of "evolvability". The
philosophical analysis of cultural evolutionary evolvability has been
pioneered in recent years by Kim Sterelny (e.g., 2001, 2003, 2006a,
2006b, 2007, 2012, 2021a). Once again, let us illustrate the general
nature of these issues by beginning in the organic realm.



The basic conditions required for natural selection--offspring
that resemble their parents with respect to fitness enhancing
traits--do not suffice for the appearance of functional traits
even if they may help explain it. The environment also needs to
cooperate: if selective pressures change very quickly then there will
be no sustained environmental demands of the sort that might build
complex adaptations over time (Boyd & Richerson 1985). Development
also matters. If ontogeny is set up in such a way that changes to any
one trait tend to be accompanied by changes to all other traits, then
cumulative adaptation will be hard to come by. Even in those cases
where a mutation contributes positively to the function of one trait,
the chances are that it will contribute negatively to fitness in
virtue of disrupting the functioning of other traits (though, see
Brown 2021). Development also needs to make a wide range of variation
available. If it is highly constrained, so that only a small number of
forms are possible, then selection is not presented with a broad
enough range of raw materials from which to fashion complex
traits.



It also seems that cumulative adaptation relies on the suppression of
"outlaws" (Sterelny 2001, 2006b, 2016, 2021b). Group
selection is often held to be an ineffective agent of group-level
adaptation, on the grounds that it is vulnerable to "subversion
from within". This occurs when individual organisms go it alone,
sabotaging complex features of group organization in favor of their
own fitness (Birch 2017). Individual-level selection, in contrast, can
build individual-level adaptations. This is because, by and large,
genes in a given human organism share a "common
fate"--they do not behave as though they were in direct
competition, struggling for representation in future generations. When
genes genuinely "go it alone", for example by sabotaging
meiosis so that some have greater chances of appearing in future
generations than others, then the overall integrity of the organism
can be compromised, and individual-level adaptation is undermined.



By applying these sorts of considerations to the cultural realm we can
understand the likely costs and benefits associated with different
modes and forms of cultural inheritance (vertical, oblique, meme-like
and so forth). We can also understand the different evolutionary
forces that might bring these different forms of cultural inheritance
into existence. In turn, these insights may facilitate comparative
work that documents the general conditions required for a species to
make use of cultural inheritance in order to build complex adaptations
such as tools. This way of thinking offers the promise, for example,
of explaining why few, if any, non-human species build progressively
more and more complex cultural features in a cumulative manner
(Richerson & Boyd 2005: 107; see also Laland 2017).



Questions relating to evolvability are also tied up with difficult
issues relating to the units-of-selection debate (Okasha 2006). As we
have seen, natural selection at a higher level of organization may be
required to generate mechanisms that suppress the ability of
disruptive "outlaws" to go it alone at lower levels of
organization. Does something like this occur in the cultural realm?
Does selection on human groups act so as to limit the ability of
individual humans to go it alone? In what ways might cultural
inheritance be involved in these processes? These questions are
complex, both in terms of how they should be posed and how they should
be answered. But some of the most interesting work in cultural
evolutionary theory may come from efforts to answer them.


### 6.5 Macroevolution



Many evolutionists have argued that biological tools can have great
value when developing a historical view of the pattern of cultural
change (see, for example, Gray, Greenhill, & Ross 2007; Mace &
Holden 2005; Lewens 2012, and the entry on
 macroevolution).
 Consider phylogenetics. A variety of biological methods have been
developed that help us to uncover the structure of evolutionary trees:
they show which taxa split from which others and when. It seems clear
that cultural items of many kinds (most obviously languages, but also
tools and techniques) also stand in recognizable genealogical
relationships, and this has led many biological anthropologists to use
phylogenetic methods borrowed or adapted from the biological sciences
to reconstruct history in the cultural realm.



Critics have sometimes followed Gould (1988) in arguing that these
biological methods cannot be properly applied to culture, because
cultural genealogies invariably take the form of reticulated networks
rather than branching trees. Cultural change is indeed often highly
reticulated: it is obvious that a complex object like a car is a
confluence of numerous technical lineages, which come together to form
the hi-fi system, the engine, the safety devices, and so forth.
Moreover, as improvements are made to cars these new developments may
be borrowed by innovators of bicycles, furniture, toys, and other
shifting constellations of artifacts.



These important observations need not undermine the project of
cultural phylogeny. One response is to look to those aspects of
culture most amenable to phylogenetic reconstruction, such as deeply
conserved linguistic terms (Cabrera 2017)--a strategy adopted by
many early adopters of phylogenetic methods. Another is to recognize
that biological evolution is also reticulated. Bacteria, for example,
do not form genealogically isolated lineages, hybridization is rife
among plants, and there is also considerable borrowing of elements of
the genome between apparently isolated mammalian species. Of course,
this might show simply that phylogenetic modes of inference are doubly
imperiled: they don't work for much of the biological world
either. But cultural evolutionists (e.g., Gray, Greenhill, & Ross
2007) are encouraged by inferential developments within biology
itself, which aim to reconstruct partially reticulated trees by
proposing so-called "reconciliations" of the conflicting
trees that traditional methods often propose for species and genes.
These have shown promise beyond the original home of cultural
phylogenetics in reconstructing trees based on language families,
extending to archaeology and technology (Jordan 2015; Gjesfjeld &
Jordan 2019).



This kind of work is important, in part because of the uses to which
well-confirmed cultural phylogenies can be put. It may be easiest to
illustrate their value via a simple example. On the face of things,
looking for correlations is a reasonable (albeit fallible) way to
discover causal relationships. If, for example, people who smoke often
get lung cancer, and people with lung cancer are often smokers, then
we have good evidence that smoking causes lung cancer (or perhaps that
lung cancer causes smoking). But there can be strong correlations that
do not indicate causation. If, for example, we find that there is a
strong correlation in animals between making a moo sound and producing
large quantities of milk, we should not conclude that one causes the
other. Mooing and milk production go together because the creatures in
question share ancestors in common, who both mooed and gave lots of
milk. Of course, in the case of cows this fact of common ancestry is
so obvious that we hardly notice how it informs our causal inference.
But cultural phylogenies are unobvious. Russell Gray, among others,
has long argued that when we understand them better, our knowledge of
phylogenies can then confirm, or undermine, causal hypotheses that are
claimed on the basis of correlation.



Gray and Watts (2017), for example, have scrutinized what is sometimes
called the Supernatural Punishment Hypothesis. This is the hypothesis
that belief in powerful gods, who inflict punishment on wrongdoers,
tends to result in societies better able to harness the fruits of
cooperation (see Norenzayan et al. 2016). Gray and Watts again caution
that mere correlation between societies that believe in
"moralising high gods" and various measures of social
complexity does not count strongly in favor of the Supernatural
Punishment Hypothesis. One must also consider the potentially
confounding consequences of shared ancestry among the societies
surveyed. Gray and Watts draw on Austronesian data to argue that
belief in moralizing high gods tends to be gained after, not before,
the emergence of political complexity. These data, they suggest,
undermine the thought that moralizing high gods drive this form of
complexity. That said, they do find some support for a weaker
supernatural punishment hypothesis based on belief in punishment
interventions from natural spirits, ancestral spirits and mythical
heroes, as well as from moralizing high gods. In their view this type
of belief facilitated, "the rise of political complexity"
without "helping sustain it" (Gray & Watts 2017:
7848). Work such as this indicates the potential for cultural
phylogenetics to inform broad-sweep hypotheses about not just the
patterns, but also the causal processes, that have marked the cultural
history of our species.



Of course, phylogenetic methods are far from the only means of
reconstructing cultural history. More recently, archaeologists have
argued for new methods and theories based on analogies between
archaeology and paleobiology. Just as paleobiologists identify
evolutionary trends and patterns by looking at the fossil
record--notably, periodic mass extinctions and rates of
speciation--suitably rich archaeological databases might allow
researchers to discern distinctive patterns, processes, and trends in
the cultural evolutionary record (Perreault 2019; Gjesfjeld et al.
2016). Perreault (2012), for instance, compares evolutionary and
archaeological datasets to quantify the oft-informally made claim that
culture evolution proceeds more quickly than biological evolution. A
different set of arguments considers how archaeological databases and
statistical techniques may help revise archaeological systematics and
cultural taxonomy (Riede et al. 2020; Lyman 2021). The two efforts are
related. Classificatory work may feedback into so-called
"macro-archaeological" work that includes discerning rates
of cultural diversification and extinction (Perreault 2019).


## 7. Conclusions



Some of the early philosophical and methodological skirmishes over
cultural evolution focused on grand visions for the promise of the
approach. So, for example, Mesoudi, Whiten, and Laland (2006) argued
that the social sciences had stagnated, while the biological sciences
had shown significant progress. They suggested that this pointed
towards an evolutionary synthesis within the social sciences that
would parallel biology's own, and which would have a form of
natural selection at its core. Perhaps unsurprisingly, such a bold set
of claims attracted vigorous responses that were equally sweeping; Tim
Ingold (2007) aimed to diagnose fundamental flaws within the entire
enterprise of cultural evolution; Fracchia and Lewontin (1999)
suggested a series of in-principle topics (associated, for example,
with phenomena of power, and with the failures of methodological
individualism) which, they argued, undermined the ability of cultural
evolutionary approaches to provide informative explanation.



This entry has pointed towards a different vision for cultural
evolutionary work. Instead of beginning with a broad diagnosis of the
supposed failures of social science, or of the presence within culture
of the general conditions required for natural selection processes to
act, the cultural evolution project can be understood in a more
eclectic manner. It seeks to explore the significance of various forms
of learning not just in humans, but in many other species. Although
this article has focused primarily on humans, cultural evolutionary
science increasingly investigates how learning influences adaptation
and diversification in primates, birds, and fish. This prompts a
series of live research questions: how widespread are these learning
abilities, and why did they arise in the first place? What explains
why some species possess them in apparently very different forms to
others? How does change brought about by learning interact with other
forms of change studied by evolutionists? What sorts of conditions are
required for learning to promote long-lasting diversification within
species? What sorts of conditions are required for learning to promote
incremental improvements with respect to functional behaviours, or
artifacts? In what ways does learning facilitate or impede the
origination of other-regarding behavior, or systems of communication?
An approach focusing on these sorts of questions is free to co-opt and
collaborate with successful research strands in the mainstream social
sciences, just as it is free to co-opt and adapt explanatory models
which sometimes have their origins in disciplines like population
genetics, but which can just as well have their origins in
epidemiology or economics.