Sunday, 23 August 2015

Symbiont kin selection

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.

Saturday, 25 July 2015

The meaning of heredity

I generally use the term "heredity" to refer to the transmission of traits from one generation to the next.

However, I notice that some sources differ - confining the idea of "heredity" further. The Encyclopedia Britannica is explicitly DNA-gene centric:here:

heredity: the sum of all biological processes by which particular characteristics are transmitted from parents to their offspring. The concept of heredity encompasses two seemingly paradoxical observations about organisms: the constancy of a species from generation to generation and the variation among individuals within a species. Constancy and variation are actually two sides of the same coin, as becomes clear in the study of genetics. Both aspects of heredity can be explained by genes, the functional units of heritable material that are found within all living cells. confines the idea of heredity even more - to organisms that experience meiosis - with this:

heredity:the transmission of genetic characters from parents to offspring: it is dependent upon the segregation and recombination of genes during meiosis and fertilization and results in the genesis of a new individual similar to others of its kind but exhibiting certain variations resulting from the particular mix of genes and their interactions with the environment.

These sources are simply wrong. However, their mistake is widespread and leads to confusion about cultural evolution. For example, Larry Moran defines evolution using the term 'heredity' - saying: "Evolution is a process that results in heritable changes in a population spread over many generations." - and then goes on to argue that:

I've already alluded to one of the classic questions that a proper definition can answer — the increased height of Europeans over the past five centuries. Armed with a good definition of biological evolution we can focus on one of the key requirements; namely, heritable change. It turns out that the increase in height is due to a better diet and not to genetic changes. Therefore, this is not evolution according to the scientific definition.

This is a serious conceptual mistake. European diet has improved (largely) through memetic evolution. Memes are passed from one generation to the next in cultural evolution - and rather obviously this should meet any sensible scientific definition of evolution - as is attested to by the now-massive literature on cultural evolution. Yet Moran dismisses it - apparently due to his conception of the definition of the term 'heredity'. This seems like a spectacular mess to me.

Larry is not alone in this evolutionary denialism. Here's Mark Ridley on why cultural evolution doesn't qualify as being "evolution":

Changes that take place in human politics, economics, history, technology and even scientific theories are sometimes loosely described as evolutionary. In this sense "evolutionary" means mainly that there has been change over time - and perhaps not in a preordained direction. [...] human ideas and institutions can sometimes spit during their history - but their history does not have such a clear-cut branching tree-like structure as does the history of life. Change and splitting provide two of the main themes in evolutionary theory.

His complaint appears to be that cultural evolution is too reticulated - one of the most dopy objections to cultural evolution ever - once you consider how reticulated bacterial evolution is.

Anyway, these days, almost everyone agrees that cultural evolution is a type of evolution. The remaining debate in the area is mostly over whether cultural evolution is Darwinian. However we obviously have a mopping-up operation to do - as some folk don't even regard cultural evolution as being a type of evolution! That position seems indefensible to me.

Sunday, 5 July 2015

In light of cultural evolution

There's a recent trollish article doing the rounds titled:

The Theory Of Evolution Does Not Apply To Modern Human Beings.

Basically it argues that humans don't behave as the theory of evolution dictates. For example, the more resources you give a human, the fewer children they have.

I think this article nicely illustrates the confusion associated with a lack of understanding of cultural evolution. Almost everything in the article makes me think: "yes: but only if you ignore cultural symbionts".

It's well-known that parasites can reduce host reproduction - and even drive hosts extinct. The demographic transition is driven by cultural symbionts that reduce host reproduction. This has been extensively modeled by cultural evolution enthusiasts. This isn't contrary to the theory of evolution - you just have to include the evolution of memes in order to understand it.

If you add resources to a human population the memes absorb the resource faster than the human hosts do - and more memes often means less host reproduction.

Something very similar happens in the organic realm - if you add sugar to a human population. A little sugar might help with reproduction - but beyond a certain point, fertility begins to decline. Instead of making more human genes, the sugar fuels the reproduction of gut microbes at the expense of the genes of the human host. The host's belly swells up to accommodate them all. Eventually the host is effectively sterilized.

This all illustrates the dictum: Nothing in human evolution makes sense - except in the light of cultural evolution.


Terence Mckenna - on memes in 1990

Terence Mckenna - on memes in 1990. From a lecture titled: 'opening the doors of creativity'.

Here are some other meme-themed videos by Terence.

Wednesday, 1 July 2015

Recombination as a meme repair mechanism

In the organic realm, the idea that recombination can repair bad genes by replacing them with good ones is one of the two main theories that accounts for the origin and maintenance of sexual recombination (the other main theory is the Red Queen hypothesis).

The idea suggests that sexual recombination results in an uneven distribution of deleterious mutations in the offspring - with some having many bad genes and others having few. Those offspring with many bad genes are culled by selection - while those with few get to try again in the next round.

Even random assortment among mating partners would produce this effect. However in practice, the best quality individuals can often seek each other out - and so have offspring with an especially-low mutational load.

The "gene repair" theory of sex has been championed by Richard Michod, among others. He presents the theory in a stimulating popular book, titled: Eros and Evolution.

MIT is in the news today with a souped-up implementation of this idea applied to computer software. They are using recombination to fix crashing programs by using code from working ones. They call their software CodePhage. Here's the associated MIT press release. Their paper is called Automatic Error Elimination by Horizontal Code Transfer across Multiple Applications. It's an interesting case of bio-inspired computing.

I think recombination is a common meme repair technique. If you realize you have a bad meme, it makes sense to find someone with a functioning copy and acquire it. Much the same applies at the level of organizations and institutions. The need to repair dysfunctional memes probably drives a significant quantity of the memetic recombination that we see in the ideosphere.

Sunday, 21 June 2015

Language - missing phylum of memetics

Language should always have been the king of the subjects studied by students of memetics and cultural evolution. Speech and writing have built-in error correction mechanisms. They are some of the things which are most likely to be copied with high fidelity - and thus to exhibit cumulative adaptations as they evolve. However linguists have not been very prominent in the field of cultural evolution. Famous students of language evolution - such as Steven Pinker and Noam Chomsky - are apparently clueless newbies when it comes to the topic.

I checked for books on the topic of the cultural evolution of language. There are:

This is a pretty small list. Also, all the books on it are very recent. When I became interested in cultural evolution, there was practically nothing.

This post asks: what happened? Why weren't linguists early adopters of memes and cultural evolution?

Though I think this is a good question, I don't have a terribly good answer. What follows are my speculations:

I think that many of the cultural evolution pioneers had backgrounds in evolution and population genetics. Most linguists would have lacked this background. They would have found much of the primary the literature hard to follow or irrelevant.

Also, until recently, cultural evolutionists were few and far between. Only in the last few years have supporters been coming out of the woodwork in large numbers. The dates on my book list reflect this. However, I think if I made corresponding lists for the cultural evolution of science, technology and religion, the 'science' and 'religion' lists would have more items on them - though the 'technology' list might have fewer.

The eusociality symbiont hypothesis and epistemic hygiene

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.

Saturday, 20 June 2015

Darwinian Metaphysics vs Universal Darwinism

Momme von Sydow has a 2012 book titled: From Darwinian Metaphysics towards Understanding the Evolution of Evolutionary Mechanisms - A Historical and Philosophical Analysis of Gene-Darwinism and Universal Darwinism. The book is freely available to read online. At almost 500 pages, it's the longest critique of Universal Darwinism I've ever seen.

It's a fairly sympathetic critique - the author makes a serious effort to understand the topic before explaining where the perceived flaws lie. As the following quotation indicates, the author regards the blindness of variation as a key tenet of Darwinism:

the Darwinian tenet of the blindness of variation is challenged. It is argued that one should interpret biological evidence in a way that allows for a kind of directed and adapted process of variation – though this process is of course fallible and not omniscient. Paradoxically, this follows from pursueing a Darwinian approach up to its limits. Darwinism thus again demonstrates that it contains the seeds of its own destruction.
It is neo-Darwinism that got dogmatic about variation being undirected. Darwin himself was fairly agnostic about this topic - and indeed proposed a mechanism by which variation was directed by the experience of organisms.

This point revolves around a debate about what the term 'Darwinism' means. Personally, I see no compelling reason to attach Darwin's name to the more useless and out-dated theory - especially when Darwin himself had nothing to do with it.

The author also seem to think universal Darwinism is incompatible with the evolution of evolutionary mechanisms, saying:

Moreover, although it cannot be questioned that we can learn very much from Darwinism, it is claimed that Universal Darwinism as an interpretative framework can and should be replaced by an account of the evolution of evolutionary mechanisms – both in biology and in metaphysics.
I think the biological trial-and-error theory of Darwinism might also be urged to drop its universalism and acknowledge a certain evolution of evolutionary mechanisms.
The evolution of evolutionary mechanisms seems like a flat fact to me. Particularly the mechanisms that produce selection and introduce variation have complexified over time. Mutations produced inside minds can be a bit different from those produced inside cells. However, as far as evolutionary theory goes, the mechanism of production of mutations can be treated like a modular block box - with specific theories from genetics being plugged into it. A new mutational mechanism needs no changes to evolutionary theory itself - rather it's just a new mutation module. Much the same goes for selection. These days, selection can be produced by intelligent agents - for example by intelligently choosing compatible mate. Darwinism is big enough to include a variety of sources of selection. I think we can have a universal Darwinism while still leaving some space for the evolution of evolutionary mechanisms.

A critic might complain that, with these dependencies on other theories of mutation and selection, Darwinism barely qualifies as a theory in its own right. This has always been true, though. For example, to predict the fitness of a bat genome, Darwinism relies on theories of development, theories of aerodynamics and theories relating to radar. Dependencies on other theories has always been a fundamental part of Darwinism. Evolutionary theory doesn't stand alone.

These are some of the main criticisms in the book. I think that universal Darwinism survives these attacks just fine.

Tuesday, 16 June 2015

Memetics vs semiotics

Some students of semiotics seem to be irritated by the success of the meme. (e.g. Kilpinen, E. (2014)). Semiotics seems to be much more popular than memetics, and the term 'sign' seems to be much more popular than the term 'meme'. However, the term 'sign' does appear to have lost some important ground to the term 'meme'. Here's my take on how the meme managed to get a foothold.

Semiotics claims to be older than memetics. Semiotics became popular in the 1970s and 1980s - but claims roots going beck centuries. However, until the 1970s there wasn't very much in the way of semiotics publications. The founders of the various schools of cultural evolution may have ignored semiotics, because it had yet to become popular at that time.

By the 1970s, semiotics had basically failed to produce a school of cultural evolution. There was no explanation of how signs evolved based on broadly Darwinian principles. As Terry Deacon put it:

Until now, classic semiotic theories have not had much to say about why certain signs persist and others do not, or why certain semiotic systems evolved the forms they now exhibit.

The meme concept has generated recent excitement precisely because it seems to offer hope of providing something that other theories of social and semiotic processes have not succeeded in providing. It addresses the process of semiosis, i.e., the dynamical logic of how the symbolic and concrete constituents of culture arise, assume the forms they assume, and evolve and change over time.

Retrospectively, we can see that application of evolutionary biology to human communication mostly arose outside of semiotics - mainly from those trained in evolutionary biology and population genetics.

Perhaps the bypassing of the term 'sign' by cultural evolutionists was inevitable. The term 'sign' - in common parlance - comes with an associated object that is signified by the sign. Culture contains many signs - for example, letters, words and ideograms. However there are also non-signs: for example, knots, cups and fire. These have no obvious referents - they just are. For the concept of 'sign' to be useful as a unit to cultural evolutionists all culture would need to be signs. However, that violates the common dictionary definition of 'sign'.

The tpyical semiotics solution to this problem is to expand the definition of 'sign' to include knots, cups and fire - and indeed, practically anything. This is sometimes called 'pansemiotics'. If you do this, then semiotics becomes very general. Of course the problem is then that the original meaning of the term 'sign' has got lost. It is sometimes permissible to give common language terms counter-intuitive technical meanings. However, here, I think it just leads to pointless confusion.

As for the claim that the concept of 'meme' misses out the concepts of semantics and observation: this is just sour grapes on the part of the semiotics folk. One might reply that meaning and observers aren't part of the meme because they are context-dependent.

Monday, 15 June 2015

The edge of evolution

The domain of Darwinian evolution has expanded dramatically over the last 150 years. Darwinian evolutionary theory is now frequently applied to cultural evolution, the development of individuals and individual learning. More speculative extensions of Darwinism include ones that cover quantum physics, complex adaptive systems, cosmological natural selection and observation selection effects.

It is natural for observers of this expansion to ask: how far can the Darwinism go? Where is the the edge of evolutionary theory? What are the limits of Darwinism?

The questions relating to "Darwinism" might be criticized as being a bit vague - but we can replace these with similar questions about the domain of concepts such as fitness selection and adaptation - and have some more rigorous questions that more people are likely to be able to form a consensus about.

I think that the lesson of history is that the edge of evolution is farther out than we think. People are inclined to say that the edge of Darwinism lies at the outer edge of their personal understanding of it. However, we can see historically that Darwinism has repeatedly pushed into new domains, covering new phenomena.

Another possible position is that there's no real "edge" - instead evolutionary theory gradually breaks down as more and of its axioms are progressively broken. I think that it is clear that there's some truth to this perspective. However, evolutionary theory is fairly simple - and there aren't very many axioms to break. Nonetheless, we should not necessarily expect to find a single precipice at the edge of evolution - but rather a gradual disintegration in the form of some steps or a slope. This complicates the issue - but doesn't fundamentally alter the problem.

To finish this article, I have a characterization of where I think the edge of evolution is to offer. I think evolutionary theory applies to macroscopically irreversible systems. This gives it roughly the same domain as maximum entropy thermodynamics - which I claim it is very similar to. Part of the intuition behind this involves the link between selection (from evolutionary theory) and destruction (which leads to many macroscopic entropy increases).

This relationship is probably wrong in detail. There's nothing in evolutionary theory that forbids its application to macroscopic reversible systems. Selection need not necessarily be linked to destruction. However, this is the best, short characterization of the edge of evolution that I have. Without it, I am reduced to offering a laundry list of phenomena that I think that evolutionary theory applies to.