I've long been promoting the symbiont hypothesis as a theory relating to the origin of cooperation and eusociality.
My previous articles on the topic include:
The theory fingers symbionts as important in the origin of cooperation, sociality and eusociality and there are obvious and far-reaching implications in cultural evolution, where memes promote social interactions between hosts in order to promote their own spread during those interactions. To quote from my 2011 article on the topic:
The idea is that meme reproduction depends on social contact between humans. Increased levels of social contact between their hosts are good for memes since this results in more reproductive opportunities for them. Memes that promote human ultrasociality have the effect of pushing humans into close proximity with each other, so the memes can infect new hosts.
I'm happy to report that there's been a recent increase in the number of scientists looking into the topic, and now there's a bit more experimental evidence bearing on the issue. Some of this work is summarized in the recent popular science article: Can Microbes Encourage Altruism?. The article mostly reports on computer simulations which demonstrate the effect - which is what I was looking for in one on my 2014 articles - but the latter part of the article covers empirical evidence from a variety of sources that microbes do, in fact encourage cooperation and social behavior in their hosts - and that this can be decreased via the use of antibiotics. The article cites recent work reporting:
fruit fly larvae are attracted to airborne chemicals released by the bacteria in their guts; the appealing scent may draw the larvae toward one another
...and...
When Bienenstock exposed mice to low-dose antibiotics in utero and soon after birth, the treated mice showed lower levels of sociability and higher levels of aggression than mice in a control group
These are still early days for the hypothesis, but the topic is clearly deserving of more research.
Update 2017-07-29: the article has now been syndicated in Scientific American.
 Bill Hamilton famously was one of the first evolutionary biologists to take parasites seriously - seeing their influence everywhere. Many have subsequently followed in his footsteps. One interesting paper on the topic which I recently took in is this one:
Gregory Cochran may be known to readers of this blog because he co-authored the book The 10,000 Year Explosion: How Civilization Accelerated Human Evolution. The paper here argues that pathogens have been consistently underestimated, and we ought to be considering them more frequently in cases where fitness is adversely affected.
The paper is all about organic pathogens. However the authors appear to be ignorant of cultural evolution, and don't extend their argument to cultural pathogens. Nor is there any discussion of meme-gene coevolution. Despite this, many of the arguments they give are equally applicable to cultural evolution.
One of the examples the paper gives is human male homosexuality. Although to date, no pathogen has been discovered that causes human male homosexuality, there's circumstantial evidence that suggests that pathogens may be involved. While thinking about cultural evolution it occurred to me that there's an example of cultural pathogens causing homosexual interactions between males: the well-known case of priests and altar boys.
It's long been argued that religious memes can sterilize priests to divert resources from genes to memes and thus promote their own propagation. Dawkins (1976) gives this argument as a hypothetical example. Homosexuality could be being promoted by memes for similar reasons. Though courtship and mating do use some resources, homosexual relationships do mostly manage to skip the cost of producing children - the resources saved could go into meme propagation.
Priests seem to go for young boys (rather than young girls) about 80-90% of the time. Indeed, the church apparently seems to be an attractive institution for homosexual men and many priests are gay. However the frequency of gay priests doesn't explain the frequency with which boys are targeted. Perhaps young girls are better guarded, or maybe they are more clearly prohibited for priests in scripture. Anyway the evidence is not conclusive, but memes do appear to be promoting male homosexual behavior in this case.
Knowledge of cultural evolution is invaluable in understanding the role of pathogens on human health. Consider the obesity epidemic, for example. That's an epidemic of Candida Albicans - and other fatness-promoting gut microbes. However it is also an epidemic of food processing technology and fast-food advertising memes. The food industrial complex develops ever-evolving tasty recipes and then uses memes as targeted vectors to deliver their their fat-promoting messages to consumers. The effects of memes and genes are tangled together in this case. Without an understanding of both you don't get the full picture.
 In a 2016 post titled Shared interests of unrelated symbionts I discussed how unrelated symbionts often had shared interests, resulting in them pulling their hosts in similar directions.
A classic example of this involves promoting interactions between hosts. In the organic realm, rabies makes hosts want to bite each other while toxoplasmosis makes hosts unafraid of each other and attracted to each other's urine. In the cultural realm, missionaries seek out potential converts and teachers seek out pupils. In each case interactions between hosts are promoted by symbionts - because they need such interactions to reproduce.
Another example is reduced fertility. Many parasites compromise host fertility - probably since host reproduction uses resources which might otherwise go into symbiont reproduction. Many parasites go in for complete host castration - they are called "parasitic castrators". Many cultural symbionts also reduce host fertility - as seen in the demographic transition. Places like Japan where there are many memes have sub-replacement fertility.
This post is mainly proposing terminology. I think we should call these shared interests a "consensus". It's the consensus of the symbionts that the hosts should get out more, meet more strangers and not have kids of their own. Of course, "consensus" is not meant literally here: no-one is suggesting that the symbionts communicate via town meetings. The consensus might be different depending on which group of symbionts are under consideration. Gut bacteria might have a consensus that the host should go the the smallest room more frequently and spend more time there - while cultural symbionts might have a quite different consensus. We could call the cultural symbiont consensus the "memetic consensus" for short.
 Symbiology is a core concept in cultural evolution. Cultural creatures act as though they are parasites, mutualists or commensals with their human hosts. This is fundamental to understanding the dynamics of their evolution. That's all about cultural evolution for this post - the rest is all about symbiology.
As part of my interest in symbiology I have recently explored the controversial work of Don Williamson on the origins of larvae. Williamson has promoted the idea of radical hybridization being involved in the origins of caterpillars into butterflies - and many other larval forms. For example here is his paper, Caterpillars evolved from onychophorans by hybridogenesis. Basically, Williamson claims that ancestors of modern butterflies may have had their eggs fertilized with sperm from velvet worms. Williamson's work has been widely ridiculed and castigated.
Like many students of symbiosis I am attracted to the possibility of biological metamorphosis arising as a result of fusion between widely separated forms. However, I think that there are more possible mechanisms than radical inter-species hybridization.
I have long thought that another possibility for the evolution of biological metamorphosis involves extended symbiosis. This idea shares the idea that larvae and adults started out as individuals members of separate species - but doesn't depend on the viability of radical hybrids. In an extended close symbiosis, parties can transfer genes gradually - via viruses or sperm-mediated gene transfer. They can also assimilate their partner's traits gradually through learning and ordinary natural selection. Radical hybrids are not needed in this kind of scenario - instead evolutionary assimilation can be gradual.
This symbiosis-based theory seems like a clear possibility to me. It holds that at one stage a wasp-like creature planted eggs in a caterpillar-like creature. These parties developed a close relationship and coevolved until one party assimilated the other. Their mutual descendants are caterpillars into butterflies. It is fairly well known that symbiosis promotes horizontal gene transfer. Mutualism, or at least mutual dependence, probably increases its likelihood.
The symbiosis hypothesis would be boosted by discoveries of wasps that have evolved mutualisms with their egg incubators. Wasps are commonly parasites and their incubators are destroyed my multiple wasps during wasp reproduction. However if a relationship develops in which one wasp hatches from one host, the situation starts to look a bit more like the caterpillar into butterfly metamorphosis scenario. Such cases are in fact known - for example, see here for an example involving a single wasp egg per incubator. Exactly how parasitism might turn into mutualism in this case is not obvious - but there are plenty of other cases where parasites have evolved into benign partners and then into obligate mutualists.
Here's another example of one wasp-per host:
Like Williamson's idea, this theory would be boosted by genetic evidence which supported gene transfer between two species. However, since it is not obvious what the ancestral species were, such evidence may remain elusive. This theory doesn't depend on such evidence existing - maybe no gene transfer was involved and one partner assimilated the other one via learning and natural selection. That makes the theory harder to refute - which is not normally considered a virtue among scientists. However, I think we need an alternative to radical hybridization that preserves the idea of separate origins - which itself is strongly suggested by the phenomenon of metamorphosis, according to multiple lines of evidence.
References
 Unrelated
symbionts tend to affect the host in similar ways. For example,
many symbionts tend to make hosts leak bodily fluids - through bleeding,
diarrhea, coughing, sneezing and pimples. Similarly, many stimulate interactions
between hosts to facilitate their own reproduction - with rabies, toxoplasmosis
and malaria being some of the best-known examples.
Can we make the same sorts of statements about cultural symbionts? I think so.
Most of the rest of this post will give examples. Speaking and writing skill
skills are a common pathway into the future for many memes. Speaking to large
audiences is especially desirable. Teaching skills are particularly useful to
many memes.
Like their organic counterparts, cultural creatures depend on contact between
their hosts for their transmission - and so many of them tend to promote
frequent, peaceful host interactions.
Another area involves resource allocation. As with organic parasites, many
cultural parasites benefit from reducing the fertility of their hosts. Resources
spent on host reproduction are resources not available for parasite reproduction.
There's a considerable body of evidence that shows that memes do tend to have this effect.
Symbionts are also interested in host lifespan. They tend to follow one of two
strategies. One involves turning the knob that controls the reproduction-maintenance
axis towards maintenance - a living host is typically more useful to symbionts than
host offspring are. This tends to increase host lifespan. The other strategy is to
burn through host resources and convert them into symbiont offspring as fast as
possible. Ebola would be an example of this strategy. This sort of thing tends
to decrease host lifespan. The second strategy is often especially harmful to the
host.
The whole phenomenon of shared symbiont interests is, I think, something useful
to be aware of. If many agents are attempting to influence you in the same direction,
that increases the chances of their collective manipulations being successful. Some
people might want to take steps to compensate.
I've previously promoted the symbiont hypothesis of cooperation and eusociality. As a brief summary, this proposes that sometimes agents cooperate because they are being manipulated into coming into contact by symbionts whose reproduction depends on interaction between their hosts. Here is my 2014 essay on the topic:
The theory has substantial significance for the evolution of eusociality in the organic realm. It also applies to the spread of cooperation in cultural evolution - based on the model that memes are the genes of cultural symbionts. Many memes promote cooperation partly because they need extended contact between humans in order for them to reproduce themselves.
One interesting illustration of the symbiont hypothesis involves Toxoplasmosis. Toxoplasmosis is caused by a microorganism that makes mice love cats - and is transmitted from mice to cats. It turns out that Toxoplasmosis also makes people love cats - and might be contributing to the plague of cat memes on the internet. Toxoplasmosis is an interesting example of a microorganism promoting love - partly because it is so well known. It makes a useful illustration of the symbiont hypothesis.
Update: for a sceptical take on the topic see here.
Cultural kin selection
proposes that cooperation can arise due to shared memes - as well as due to shared DNA genes.
However, cultural kin selection can be thought of as a special case of symbiont kin selection - an idea
that may apply to many types of close living organisms.
Colony life - as found in ants, bees and mole rats - leads to increased levels of transfer of symbionts
between the organisms involved (often due to sheer close proximity). The mole rats eat each others
feces - and so come to share the bacteria they need to digest their tubers. Ants frequently cultivate
fungi - and their nests are heavily dominated by fungi digesting rotting wood. They have many other
symbionts too - there are special bacteria that they use to suppress the growth of competing strains
of fungi, for example.
As well as acting on the host genes, kin selection acts on the genes of the symbionts too. If the
symbionts in different organisms are related, then - to the extent that these can manipulate the behaviour
of their hosts in favour of cooperation - they will tend to do so.
Probably ant fungus is the most extreme example of this form of kin selection. Though distributed the fungus
is closely related - more so than the ants themselves are. It forms something like a massive multi-cellular
organism in each ant colony - a superorganism. It may benefit from that ants acting as a coordinated whole
more than the ants themselves do. The ants snack on the fungus - so it probably has a variety
of ways of manipulating ant behaviour - through taste, smell and direct chemical action.
Seen from the crude perspective of Hamilton's rule, shared symbiont genes may elevate relatedness further.
For example, intra-colony relatedness in naked mole rats has been estimated to be 0.81 - but this
relatedness figure is based on the host genes. As with other mammals, most of the genes involved
are not mole rat nuclear DNA, but are genes in gut microorganisms. The bacterial cells outnumber
those of their hosts by a factor of ten. What happens to that relatedness figure once "horizontal"
sharing of bacteria is accounted for? It probably goes up: a lot of those bacteria will be asexual
clones.
For an example relevant to humans but still involving DNA genes, consider yeasts - as found in bread, wine and beer. Many yeasts
have become human-transmitted symbionts. The main way they spread their genes around in the world
involves human social contact. If they can somehow make their human hosts socialize more with other
humans, they are likely to directly benefit. Kombucha
may be one of the best examples of a socially-transmitted yeast - since it often spreads directly
through peer-to-peer contact. Are Kombucha enthusiasts more sociable than other humans? Probably. But are they
more sociable as a result of being manipulated by the Kombucha? It is an interesting question that
deserves further study.
Symbiont kin selection is a bit different from
the symbiont hypothesis
of social evolution - but it is fair to say that these ideas are related.
Symbiont kin selection should illuminate cultural kin selection,
which can be accurately modelled as a special case of it involving cultural symbionts - rather than DNA-based ones.
Symbiont kin selection is a neglected idea in social evolution. Because of lack of study, it is
not easy to assess its overall significance - but it could easily be a big deal. If you look at humans,
a lot of their cooperation is based on shared memes - rather than shared genes. In the workplace,
for example, shared memes are ubiquitous - and shared genes are rare. Even within family life,
shared memes are ubiquitous. Cultural kin selection could easily explain more cooperation than
genetic kin selection does. This example illustrates the potential power of symbiont kin selection -
but maybe it is equally powerful in other eusocial creatures. More powerful, maybe - since they are
further along in the road to colony life than we are. Symbiont kin selection could easily be
stronger in them than it is in us.
 The eusociality
symbiont hypothesis relating to the evolution of eusociality
pictures a positive feedback loop of interactions between hosts
and symbionts, with each new symbiont pulling the colony tighter
together as the symbionts manipulate their hosts into coming into
contact with each other in order to reproduce.
The positive feedback loop involved in the hypothesis is counteracted
by negative interactions involving hosts and symbionts - in other
words by parasitism. As hosts interact more closely parasites can also
spread horizontally between them. Since horizontal transmission promotes
misalignment between host genes and parasite genes, after a certain point,
parasites start to dominate more helpful symbionts - and then the hosts
start to behave as though they want to live further apart from one another.
The significance of parasites is evident in most social insect colonies.
These are vulnerable to parasitism - due to the close proximity of the
members - and it is not uncommon to see nests obliterated by parasites.
On the other hand, because of the parasite threat, the nests themselves
are often policed by cleaning squads. Disease eradication is a big theme.
Sick individuals are exiled and everything is kept remarkably clean.
Humans are a case study for the eusociality symbiont hypothesis. Our
symbionts are typically cultural, but the basic dynamics are much the
same - the cultural symbionts manipulate the humans into coming into
contact with each other in order to reproduce. The result is human
ultrasociality.
We know that humans living in close proximity are
more vulnerable to horizontal transmission of genes. We can see this
by comparing sick city dwellers with their more healthy country cousins.
Parasite transmission favors situations where humans are crowded together.
We have institutions to deal with this - such as hospitals.
Close proximity also favors horizontal memetic transfer. Assuming that
humans want to avoid exploitation by deleterious memetic parasites, we
are going to need organizations and institutions that promote epistemic
hygine. These will involve schools, as well as other types of training
more focused on the memetic immune system.
The negative effects of memetic parasites are clearly evident today.
We have an obesity epidemic driven by fast food advertising. There
are smoking, drinking and caffination epidemics which are widespread.
Over the counter drugs are widely abused. Paranoia epidemics are
fostered by the news media with resulting scares about terrorism,
global warming, vaccination, resource depletion, and so forth.
Epistemic hygiene can reasonably be expected to become a big focus.
Not necessarily the 'thought police' pictured by George Orwell - but
other government-level infrastructure to protect populations against
the negative effects of bad
memes.
 I've previously documented the poor penetration of
understanding of symbiology in cultural evolution in academia
in my article Symbiology adoption sluggish.
As my cultural symbiology bibliography indicates there is some understanding of cultural symbiology out there. Dennett, Blackmore, Gontier - and so on - but most students of cultural evolution within academia just don't seem to get it. There's talk of "coevolution" - but if you look deeper, this is lip service, most of the people involved really don't understand symbiology. The terms 'parasite' and 'virus' are seldom mentioned.
Epidemiological models of cultural transmission are systematically neglected - and so on.
To be clear, symbiology is an important foundation of the theory of cultural evolution. If you don't see culture as
composed of cultural symbionts coevolving with human hosts, you don't really understand the topic. Without symbiology there's no way to properly understand cultural evolution. So: what are the academics doing? Why don't they understand?
One clear factor is cultural evolution's
scientific lag. Symbiology proved hard for ordinary evolutionary biologists to understand. It wasn't until the 1960s-1980s that the implications began to sink in. These days we know from gene sequencing that the human genome is at least 8% virus. Symnbiology has proven itself to be a very significant evolutionary phenomenon. However, understanding of cultural evolution lags behind understanding of organic evolution. As a result, cultural evolution in academia is stuck back somewhere before the 1960s - back when symbiology was not properly understood.
Another factor may be that symbiology itself was a slow starter. Even in the 1980s understanding of symbiology grew slowly. Its main popularizer was Lynn Margulis - and Lynn was an idiosyncratic individual who seemed to have difficulty expressing herself clearly. She promoted symbiology, which helped it to grow - but no doubt some people didn't get the message because of the medium.
I think another factor is balkanization. Many academics are specialists. Cultural symbiology requires understanding of topics which have historically been widely separated - cultural anthropology and symbiology. This understanding hasn't been properly combined in a sufficiently large number of individuals for it to become widely known.
Another factor may be founder effects. The modern theory of cultural evolution was pioneered by a few individuals. By chance, they lacked the required memes, and didn't have the predisposition to acquire them. The modern theory has radiated from them. Under this model, the problem was bad luck, sampling effects and then magnification.
Memetics pioneered cultural symbiology. It was prominently there from the beginning - in the writings of Cloak (1975) and Dawkins (1976). It is frustrating to see the current level of ignorance in academia surrounding this topic. People are ignorant of the topic only to the extent to which they neglect the memetics literature.
 This is a call for programmers interested in the symbiont hypothesis of social evolution.
I've covered the symbiont hypothesis of eusociality before - e.g. see my 2011 book - or:
This is a big and important hypothesis relating to the origin of social organization and eusociality. However, it seems
to have become absurdly neglected in modern times - where kin
selection has got almost all of the limelight.
The field urgently needs more study. It needs computer simulation. In particular, I am thinking about
simple agent-based models, or cellular automata - that illustrate its basic idea - that the introduction
of symbionts can promote social behaviour. In a termite-like model - where the symbionts directly benefit
the hosts, it is pretty obvious that this will happen. However there are an abundance of open questions
in this area - associated with how model parameters affect the resulting evolutionary dynamics.
Science needs a lot of models in this general area to resolve these questions. So far, as far as I can
tell, very few of these models have been constructed.
A basic model might feature hosts, symbionts and walls - creating an environment with cave-like
enclosures. Step 1 would be to find some parameter settings where the introduction of symbionts
favoured cave-dwelling hosts that interacted with each other more frequently - more effectively
spreading the symbionts to newborns.
If you are a programmer with a scientific bent, you can help to resolve the questions associated with these models.
If you do a reasonable job, you will probably go down in history in the process for doing so.
This is work of large social and political significance. Humans have cultural symbionts,
which make them cooperate. The cultural symbionts make the large difference between modern humans and
primitive cavemen. However, because of low levels of scientific study of the symbiont hypothesis of
eusociality, science still has a relatively poor understanding of exactly how and why they do this.
The study of cooperation has been an active topic historically - partly as a result of this social
and political significance. However the symbiont hypothesis of eusociality has been enormously
neglected. I think most workers in the field don't understand it - or its importance.
 One of the things which I associate with the symbiology revolution of the 1960s and 1980s is
a much bigger emphasis on the significance of merging and joining
in evolution. If you look at the modern synthesis of the 1930/40s, merging and joining were
missing pieces of the puzzle back then.
Symbiology brought with it a flood of understanding of the significance of evolution via
aggregation. Now we know that merging and joining are large and important aspects of
organic and cultural evolution. Merging and joining are fundamental in sexual recombination
and parasitism - both of which are extremely widespread in both the organic and cultural
realms.
Merging and joining between species are not evolutionary phenomena which are confined to
microorganisms. Current estimates are that around 8% of human DNA comes from viruses -
rather than from our ancestors. This gives some indication of how significant between-species joining is in the evolution of multicellular eucaryotes.
The idea of splitting-only evolution still persists in some areas - like an hangover.
Evolution is still sometimes characterised as "descent with modification". Or people
say that evolution consists of "inheritance with variation and selection". These are
splitting-only descriptions of evolution. The idea of a "tree of life" is common, but not
very accurate. Life is web-like - much more so than most trees are.
It's true that splitting is more common than merging and joining. However,
merging and joining are pretty significant. They are how living things
combine their solutions to environmental problems.
The issue relates to cultural evolution. Krobner (1948) argued that
organic evolution was tree-like while cultural evolution was web-like. He
used the diagram associated with this post to illustrate his point.
However, we now know that both the organic and cultural realms exhibit
web-like evolution. The picture of organic evolution as consisting of
splitting without merging or joining has proved to be a mistaken one. Instead,
merging and joining have turned out to be ubiquitous evolutionary phenomena -
present in both realms.
References
 Joint phenotypes arise when multple individuals contribute to a trait. For example, an oak apple (see photograph on right) is the joint phenotype of an oak tree and a gall wasp. Similarly, a placenta as the joint phenotype of a mother and their offspring. The idea of a joint phenotype is an important concept in symbiology.
The idea of a joint phenotype is an important one in human cultural evolution - where most traits are phenotypes of both particular human hosts and cultural creatures.
For example, when someone sings "happy birthday to you" the resulting performance is the produce of both host genes and song memes.
A recent paper by David Queller discusses the idea of joint phenotypes observing that most cases of conflict between organisms over how local regions of space should be organized can be phrased in terms of relative contributions to joint phenotypes.
With joint phenotypes it is often possible to quantify the contribution of each host by asking what proportion of the observed variation in the trait each is responsible for. Of course to do this, you have to be able to measure the trait in question, and often there are multiple ways of doing this that can potentially provide different results. For example, in the case of the "happy birthday to you" song, the average pitch of the notes in the song is likely be mostly the product of host genes, while the relative pitch of each consecutive pair of notes is mostly the product of song memes.
Nonetheless, the idea of measuring joint phenotypes in this way represents a powerful tool for students of cultural evolution seeking to quantify the relative influences of genes and memes on particular traits.
 Numerous students of cultural evolution have got a lot of mileage over the years out of viewing animal brains as the central locus of cultural evolution. Brains are envisaged as repositories of cultural information that selectively adopt it and selectively transmit the cultural information to other creatures.
It's always been a central thesis of memetics that this is only one way of looking at the situation. As well as focusing on the cultural hosts, one can alternatively model the cultural symbionts themselves. The cultural symbionts have their own life cycles and lineages - which are independent of those of their hosts. From this perspective the hosts are one part of the environment. The environment includes multiple other copying devices (such as printing presses) and multiple other sources of selection (such as fires). Animal brains are just one part of this bigger and better picture.
It is worth noting that biology has gone through this conceptual revolution once before. It was once not widely recognized that many diseases were caused by microscopic pathogens - such as bacteria and viruses. The germ theory of disease was developed in the 19th century. Before that time, many diseases were modeled in a variety of ways using many inaccurate theories. Miasma theory held that some contagious diseases were the result of airborne pollutants. Sometimes pathologies were considered to be the results of hauntings, curses, karma, witchcraft or the work of the gods. Some of the theories came close to the right answer. The ideas of demonology and possession attributed some maladies to the actions of external agents that lived inside the host's body. These theories were partly validated by the germ theory of disease - though the causitive agents turned out to be rather different.
I think we are now facing a situation which is similar to that faced by 19th century physicians - with the modern study of culture. The cultural equivalent of the germ theory of disease is the the germ theory of culture. This was proposed by Cloak (1975) and Dawkins (1976). As with the germ theory of disease, the idea faced resistance, and took a considerable quantity of time to be widely adopted - 50 years approximately. Memetics further supports the basic model present in demonology and possession - that pathology is caused by invasion of hostile agents from outside the body - which can potentially be evicted again.
Today people routinely talk about culture "going viral". Cultural epidemiology has been enshrined in the dictionary - in the form of "memes" and "contagions" - which dictionaries explicitly acknowledge take cultural forms. However, the whole the idea still faces resistance within academia. Many still just don't understand that "viruses of the mind" are real things that can cause or contribute to pathologies. The concept is widely denigrated as being an imperfect "analogy". Others describe fear of manipulation by microscopic entities as "Darwinian Paranoia". Others opine that cultures are complex wholes that can't be meaningfully split up into germ-like pieces - and so on.
It is rather tragic to watch this situation unfolding - in the light of all those who died during the development of the germ theory of disease. You might think we had learned that small, information-carrying entities that can be transmitted between hosts can cause real problems. A wider recognition of the germ theory of culture seems likely to lead to more and better diagnosis and treatments of transmissible pathologies - just as happened with the the germ theory of disease.
 My last post referred to a paper which referenced:
I have some comments on that paper as well. I think it is a bad paper. The authors claim to have found:
key differences between the two domains that compromise, we think, the attempt to understand cultural evolution on par with genetic evolution.
The paper concludes:
This suggests that in each domain, specific cognitive mechanisms lead to the emergence of domain-specific cultural dynamics. There is therefore no particular reason to build models of cultural evolution based on an analogy with population genetics (Daly 1982).
It is true that there are domain-specific cultural dynamics. However, there are also domain-specific dynamics in the organic realm. That doesn't prevent models from population genetics being useful there. It seems to me that the merit of models based on techniques from population genetics in cultural evolution has been well established empirically over the last four decades. The authors don't really present a case which counters this large body of work.
Instead they focus on the issue of "Transmission Modes" - which they define as follows:
A central feature of population genetics is the reliance on the concept of transmission modes (TMs). A TM is a way in which genetic material is transmitted between individuals.
The authors claim in the abstract:
Modes of cultural transmission are, by analogy with modes of genetic transmission, ways in which cultural information is transmitted between individuals. Despite its importance across the behavioral sciences and for theories of cultural evolution, no attempts have been made, to our knowledge, to critically analyze this analogy. We here aim at such detailed comparison and show that the fundamental role of modes of transmission in biology results mainly from two properties of genetic transmission: (1) what is transmitted generally does not influence the way in which it is transmitted; (2) there is a limited number of simple and stable modes.
However to my mind they fail to establish either of these points.
There are an enormous number of methods of transmission in the organic realm. Genes may be transmitted between individuals by sneezes, by sexual intercourse, by contaminated water, by blood transfusions, by biting insects - and so on and so forth. If you are classifying transmission methods into discrete "modes" and arguing that these differ in number in cultural and organic evolution, the you should present a classification scheme, and argue for its utility in both domains. However, the authors present no methodology for doing that. Also, few other authors do that: "transmission method" is a much more common phrase in genetics than "transmission mode" is - as can easily be seen by performing some searches.
Saying that a transmission mode is "a way in which genetic material is transmitted between individuals seems vague. Are mosquito bites and tick bites different "ways" of transmitting genetic material between individuals? Or is it one "way" - on the grounds that both are biting insects? Are coughing and sneezing different transmission modes? - or one mode? - on the grounds that both involve airborne particles. The authors don't say - and don't provide any way of answering such questions.
Since they don't defend a classification scheme for transmission methods, it seems to me that they have failed to substantiate their case that the organic realm features a limited number of simple and stable transmission modes. Looking at the range and diversity of transmission methods in the organic realm, this claim seems implausible to me.
Also in the organic realm, what is transmitted very often does influence the way in which it is transmitted. When a cold virus is transmitted, it makes the host sneeze. When a warts virus is transmitted it makes the host itch. When a stomach bug is transmitted, the host gets diarrhoea - and so on and so forth. Where there are multiple tranmission methods, mutations may alter the balance between them - showing that genetic control over the transmission method exists.
For me, these simple observations cause the whole thesis of the paper to collapse.
Interestingly, the paper describes itself in grandiose terms, saying:
This article therefore specifies the fundamental properties upon which the analogy between cultural and genetic transmission modes rest, suggests different interpretations of previous data, raises challenging modeling opportunities and develops a new hypothesis regarding the origin of the difference between biological and cultural transmission.
I think this captures some of the excitement of those who seek to characterize the differences between the cultural and organic realms. These explorers are seeking out new laws and new principles. However, step one for scientists is to familiarize yourself with the existing literature. Often, once you have done that, not everything looks quite so new and shiny. To me, many of the supposed innovations associated with cultural evolution fit into the category of phenomena that have already been characterized by evolutionists.
 Memetics takes the relationship between the organic and cultural realms more seriously than any other theory of cultural evolution I am aware of. However, the close parallels seen by memeticists are not always shared by cultural evolution enthusiasts in academia. Alberto Acerbi helps us to highlight this difference in perspective today. To him, the close parallel seems wrong - and he explains why.
He recently posted about the differences between organic and cultural evolution on his blog. Here's one of his comments:
Moreover, a part from having effects in cultural dynamics, regulatory traits represent a difference between cultural and biological evolution. This is an “hot” topic in modern cultural evolutionary theory so I do not want to go in depth here (let me just say at least that I think it is interesting to study also the differences between the two evolutionary processes). “Rules” of genetic transmission tend to not be under genetic control, and models of cultural evolution inspired by evolutionary biology tend to consider the rules of cultural transmission (for example the propensity to learn from others) in the same way not under “cultural control” (they are usually considered under genetic control).
...and here's my reply - in which I explain why I regard the parallel as being closer:
Surely, everyone believes that the rules of genetic transmission are under genetic control! Probably, you are talking about how easy the rules are to change by making genetic modifications.
Note that, if you are comparing genetic with cultural evolution, you should really be looking at whether the capacity of organisms to transmit DNA-based symbiotes (e.g. gut bacteria, and parasites) is easy to change by making genetic modifications. In which case, you will see that the way in which such genes are transmitted is relatively malleable. It is easy enough for genetic changes to make an organism more or less likely to sneeze, for instance.
If you adopt this perspective on evolution in the organic realm, you will see that the case of DNA-based symbionts turns out to be closely comparable to the case of cultural symbionts - with respect to how easy it is for DNA to modulate the transmission pathways involved.
If anyone has ever reasoned from organic evolution to cultural evolution - arguing that since genetic transmission is not easy for genes to regulate, it will not be easy for culture to regulate cultural transmission - then probably their understanding of the dynamics of genetic transmission is faulty. There's no need to question their understanding of the relationship between organic evolution to cultural evolution on these grounds - since this is an example of where these processes are very similar. There are, in fact, plenty of known cases where genes can easily regulate the transmission pathways of other genes residing in symbionts.
In the associated paper, the authors say:
Although more flexible modalities of gene transfer exist [34, 35], genes typically propagate to offspring from just two (sexual reproduction of chromosomal DNA) or one parent (asexual reproduction or sexual reproduction of mithocondrial DNA). Cultural information instead can be transmitted in many different ways and, potentially, from any individual to any other individual, which creates the opportunity to regulate the flow of information in a more fine–grained and context–dependent way.
Cultural information typically propagates from one (or sometimes more) parents to offspring as well. However, the parents aren't human, they are cultural. For example, the parent of a bible is typically another bible. To conceptually mix together human hosts with cultural descendants would be to muddle together cultural and organic evolution. If you do that, you typically do get into a muddle about these issues - but the solution is to not do that. Humans aren't the "parents" of cultural information. They are the parents of their own children. Cultural information is unrelated to them. It's in a completely different lineage, which almost never recombines with human genes.
In both the organic and cultural realms, symbionts may potentially be transferred from any individual to any other individual. Organic symbionts - such as flu viruses may be passed between any two individuals. Similarly, in cultural evolution, bibles may be passed between any two individuals. The situation is a pretty close parallel in this regard. That's because both cultural and organic evolution are implementations of universal Darwinian rules.
Of course, there are differences between cultural and organic evolution - but they are more subtle than this. A failure to recognize the similarities results in existing work not being reused - and reinvention-of-the-wheel syndrome. Also, exaggeration of the differences hampers the development of a unified theory that covers both the cultural and organic realms. We have known about the importance of symbiosis for a long time. Culture is well modeled within a biological framework using the idea of cultural symbionts - and the existing theory of symbiosis - as was recognized long ago by the cultural evolution pioneers Ted Cloak and Richard Dawkins.
It is frustrating for me to see modern students of cultural evolution struggling to understand the topic without using the concept of symbiosis. In 2011, Alex Mesoudi managed to write a whole book on the topic without event mentioning concepts from symbiosis at all. To me, it all seems a bit like time-traveling back to the 1950s - before the idea of symbiosis was widely understood.
References
The following diagram shows a two dimensional representation of an asexual species with
the ability to learn exploring a fitness landscape.
Time is vertical, green bars represent DNA-based hosts, red bars represent ideas being copied
inside their hosts' brains. Social learning is not represented in the diagram - for the sake
of simplicity - so the red learned variants are destroyed when their associated hosts die, but
the reader can imagine what social-transmission would look like, if it was illustrated on this diagram.
The learned variation alters the environment the hosts are selected in - and so influences their
evolution. There is no attempt to illustrate this in the diagram, though.
The basic point in this post is to illustrate the similarity between this diagram, and plant roots:
The diagrams look similar because both represent evolutionary tress. In both cases, the ancestors are neared to the root than the descendants.
Indeed, the resemblance is closer than it may at first appear - since the plant roots are hosts
to mycorrhizal fungi. So, in both cases, there's a host and small, rapidly-reproducing symbionts.
The symbionts explore the surrounding space, and help to determine the path that their host takes through that space.
In my book on memetics, I make a somewhat-related
comparison, comparing brains with tree root nodules.
 The "gene" revolution in evolutionary biology came after the discovery of the
molecular basis of DNA genes - and around the time that kin selection came on
the scene. Probably both events were significant facilitators of the revolution.
Cultural kin selection
has been fairly rarely mentioned until recently, and there's a lot to say about it - as I am finding out by
writing by book chapters about cultural nepotism, and cultural eusociality.
Kin selection - more than most aspects of biology - forces you to adopt the genes' eye view, in order to understand which behaviours are likely to promote which genes. It's the same with cultural kin selection: you're really forced to adopt the meme's eye view - in order to understand what is going on.
Another factor that parallels the situation in the organic realm is group selection enthusiasm. In the 1960s, many of the same topics that were eventually modeled with kin selection were attributed to group selection. When kin selection came along, with its explicit quantitative models of relatedness - it more or less ate group selection's lunch. I expect a broadly similar phenomenon to take place in the realm of cultural evolution.
This picture of parallels between the sciences of cultural and organic evolution puts academic cultural evolution some 40 years behind the organic evolution. Other pointers suggest that sort of lag as well - for instance the poor understanding of symbiology. Of course, in some respects things are both more and less advanced. Cultural evolution still lags behind where evolutionary theory was the 1930s - in some respects - while a few individual pioneers have raced on ahead.
The good news is that cultural evolution seems to be slowly catching up. Science done on internet time looks a little different. In the last five years, the picture of the field has changed dramatically.
Delegation is an important type of biological interaction. In general, optimizers often find it beneficial to delegate tasks or functions to other optimizers. Delegation is common in mutualistic relationships.
An example of delegation occurs with gut bacteria. We can't break down foods as well as they can
so we delegate this task to them. Another task we have some difficulty in performing alone is
photosynthesis. However, we need to harvest energy from the sun to live. This task is delegated
to plants, which we then eat or burn, and these days to solar panels as well.
Delegating tasks to other agents is often beneficial. However it also has certain
risks associated with it. One is that the agents that you are delegating to go extinct.
If this happens sometimes other ones can be substituted which play the role instead.
Or sometimes, the organism has to struggle on without a partner. This latter phenomenon
has been ably documented in the book The Ghosts of Evolution: Nonsensical Fruit, Missing Partners, and Other Ecological Anachronisms.
Another problem with delegation is that the symbionts have their own goals and these can cause problems. For example, while most gut bacteria are desirable, some cause diarrhea. Steve Jobs illustrates another example of how delegation can cause problems. He founded the Apple computer company, it grew - and the result was that Steve was removed from his managerial duties as head of the Macintosh division and eventually left Apple completely.
Delegation is relevant to within-brain evolution. Genetic optimisers construct brains
and delegate their tasks to psychological optimizers. Genes require nutrients to
survive and in animals the task of obtaining nutrients has been delegates to a
separate evolving structure (the brain). This adapts to a changing environment
much faster than the organism's genes do, but has a somewhat different optimization
target (sometimes referred to as happiness). Often the two optimizing systems work
together (and the organism becomes happy, fat and then pregnant). However sometimes
things don't work out so well, and the organism may become pathologically obese, or
turn into a heroin addict.
Delegation is relevant to cultural evolution because genes have often delegated tasks
to brains, which in turn have delegated them to memes. Rather than programming behaviour
directly, human genes have built flexible brains which can adapt to their environment
rapidly. Those brains have, in turn, found it beneficial to avoid controlling behaviour
directly, but instead to hand control over to "cultural software" - which has been downloaded
from the ideosphere. This double layer of delegated control structures is part of what
makes human behaviour so flexible and complex. In practice, there are often other levels of
delegation: our cultural software often tells us to delegate tasks to other agents, or to
"technological optimisers", such as computers.
Delegation it is part of symbiology. It is part of a more general process in which agents use (or manipulate) other agents. Related concepts include:
Slowly-reproducing agents often find it beneficial to delegate tasks to smaller, more rapidly-reproducing ones. This is because large organisms use small symbiotes to adapt quickly.
Vicarious selection
The concept of delegation has typically been discussed in the context of evolutionary theory as a form of "vicarious selection". The similar term "vicarious forces" was made popular by Donald Campbell (1965 and 1974).
Various theorists have previously related the idea to cultural evolution. F. Heylighen, & C. Joslyn (1992) published on the topic. Agner Fog (1999) introduces the idea as follows:
Cultural selection processes can often be described as vicarious selection (Campbell 1965. The concept is also sometimes called preselection). The principle behind vicarious selection is that a slow and ineffective selection process is supplanted by a faster and more effective selection process leading in approximately the same direction, whereby the adaptability is increased. The vicarious mechanism is in some way created by the old selection process, and may possibly be checked by the latter - albeit ineffectively - if it runs away. Campbell mentions our choice of food as an example. If we eat something inappropriate we may die from malnutrition or poisoning, so the choice of food is ultimately determined by natural selection. Our immediate choice, however, is based on taste. The genetic evolution has designed our sense of taste in such a way that healthy food tastes good. The taste criterion is approximately equal to the criterion of nourishment, and in this way the selection based on taste has become a replacement for the much slower selection based on survival.
He concludes:
The concept of vicarious selection is important because the cultural selection process as a whole acts vicariously for the genetic selection, and indeed very effectively so.
As you can probably see from this page, I do not approve of the "vicarious selection" terminology. I think it is jargon. I feel about it the same way as I would if we called imitation "mimicry selection" or if we called coercion "threat selection". "Delegation" is a perfectly good term - and I think that biologists should make use of it.
Some folk sometimes use the terminology "principal–agent problem". This terminology also makes little sense to me. It is surely better to use the "delegation" terminology rather than using the term "principal-agent".
References
 Universal Darwinism requires a generalised theory of symbiosis.
Currently this area is largely covered by the concept of a biological interaction.
The theory of biological interaction uses the terminology of symbiosis - although the conventional definition of symbiosis specifies close interactions and excludes competition.
The terminology is illustrated in the following table (showing combinations of fitness deltas):
What's the best way of expanding the theory of symbiosis to cover all biological interactions?
The most obvious option is just to ditch the traditional concept of symbiosis, and redefine it to refer to any form of biological interaction. The terms "competition" and "predation" already cover practically any level of interaction between the parties.
Another option involves adding the following terms: - Protosymbiosis;
- Protomutualism;
- Protocompetition;
- Protoamensalism;
- Protocommensalism;
- Protopredation;
- Protoparasitism.
These terms refer to biological interactions in which neither of the parties have been interacting with each other for long enough to be adapted to the other's presence.
The second option has the virtue of not demanding redical redefinition of the terms "mutialism" and "symbiosis". It does redefine the more-common terms "competition" and "predation", though.
The idea is based on the concept of protocooperation. Under the proposal, this term would become a largely-redundant near synonym of "protomutualism".
I think we have to choose between these two options - or very similar ones. The existing situation is an irregualar and unsustainable mess - a terminological hangover.
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