Tuesday, 30 September 2014

An argument against the possibility of a memetic takeover

The paper Cultural transmission and the evolution of human behaviour: a general approach based on the Price equation ...discusses whether cultural evolution can ever break free of DNA-based evolution. It argues against the possibility of a memetic takeover. This goes against many experts in the field of artificial intelligence - who believe that humans might act as an organic bootloader for future superintelligent machines - what I call a memetic takeover. The authors of the paper ask:

Does our analysis suggest cultural evolution represents an autonomous system? In other words, once cultural transmission is in place, does cultural evolution generally operate in an ancillary role, handmaiden of genetic adaptation, or does it break free of the influence of genetic evolution completely?

Their answer is:

although cultural fitness is a distinct quantity, if it is not aligned with genetic fitness, then there is genetic selection to change the learning rules that underpin cultural transmission, making minds more discriminating. For these reasons, cultural evolution cannot become completely autonomous. In this, we echo Lumsden & Wilson’s (1981) famous conclusion that ‘genetic natural selection operates in such a way as to keep culture on a leash’ (p. 13)

I'm sorry - but this argument is a joke. It is not logically coherent. A. G. Cairns-Smith pointed out long ago that genetic takeovers were possible - describing the mechanism by which they could happen. The following diagram illustrates the process.

Just because there's selection acting on DNA that acts against it being phased out, that doesn't mean that we are stuck with DNA forever. I'm sure that there was selection on Dodos being phased out - but nonetheless, we don't have any Dodos any more. Just because selection at one level favours some outcome, it doesn't follow that that outcome will happen.

The exact same analysis "proves" that parasites will never wipe out their host species. However there are known cases of parasites driving their hosts to extinction. For example, according to a reference given at the end of this article, there is very good evidence that avian malaria and birdpox were responsible for the extinction of a substantial proportion of the Hawaiian avifauna in the late nineteenth century. Parasites can cause population instability that leads to increased risk of stochastic extinction. Or they can just decimate their host populations through gradual attenuation. Extinction of host populations becomes more likely when the parasites have multiple host species - and are not dependent on any one of them. So, when memes are no longer completely dependent on humans for their reproduction - and are capable of reproducing independently via networked machines, that's when the humans should start to watch out.

You can't plan to avoid particular outcomes if you have a theoretical precommitment to the idea that those outcomes are impossible. The idea that Wilson's leash is necessarily a permanent restraint is not just a silly mistake, it is a dangerous delusion - which it is important that not too many people buy into.

The analysis by these authors is so bad, its embarrassing. Cultural evolution really can help us to understand and navigate the future evolution of the human species. Just because some people have managed to mis-apply the theory and come to silly conclusions, that should not be taken as a reflection on the whole theory.

References

Monday, 29 September 2014

Criticisms of cultural kin selection

Cultural kin selection has faced some criticism. I'll try and track some of the most common objections on this page:

  1. Humans are good at tracking relationships

    In 2008, Boyd and Richerson expressed frank incredulity at the idea that humans are being fooled into thinking that non-relative are relatives - and so behaving nicely towards them. They wrote:

    Living primates are very good at discriminating between relatives and non-relatives and behave very differently toward each. It is hard to see why early hominids should have been less discriminating in their behavior.

    I don't think this is a particularly challenging puzzle. Most primates don't live with rapidly-evolving cultural symbionts who need to manipulate them into coming into peaceful contact with other members of their own species in order to allow the symbionts to reproduce.

    Additionally, memes don't just regard other humans as potential homes of their own future offspring. Other humans are often existing containers for their own offspring, parents and siblings. Memes use the kin-detection mechanisms in human hosts to preserve copies of themselves in other bodies via host manipulation.

    It is these cultural symbionts - which humans have and most other animals don't - that means that the human kin-recognition mechanisms are so frequently the target of successful manipulative attacks. Essentially: the cultural symbionts have short generation times, evolve rapidly and actively seek out the holes in the host kin-recognition psychology.

    Anthropologists have long recognized that kin categories are indeed influenced by culture. For example, they have distinguished between "biological kinship" and "social kinship" (Hawkes, 1983) and between "natural kin" and "nurtural kin" (Watson, 1983). That kinship relationships can be significantly influenced by culture is really a commonplace fact these days.

    Also, other species are not completely immune from this sort of kinship-based manipulation. For example, cuckoo hosts are regularly fooled into thinking that cuckoo chicks are their kin - and into providing resources for them. Notice that active manipulation by a symbiont is also involved in this case. In the case of cuckoos, succeess comes to them not because their genes evolve rapidly compared to their host - but because they are relatively rare - and so are not worth defending better against.

    Lastly, I think that there's a bit of a straw man in the framing of this objection. In cultural kin selection, people are not normally literally fooled into thinking that non-relative are really relatives. Instead they are fed sensory sitmulii that act as a superstimulus to kin detection routines in their unconscious minds. If you ask brother Mark whether brother John is a blood relative, he will probably give the correct answer. However this doesn't mean that their shared memes and shared monastic robes aren't relevant to the extent of their cooperation. Manipulation can take place unconsciously. Also: relatedness isn't a binary quantity; there are degrees of relatedness. Memes can and do massively increase levels of perceived relatedness between their human hosts - and it makes sense that they do this partly to increase their own inclusive fitness.

  2. Relatedness is hard to estimate in cultural evolution

    Here is Peter Richerson in 2010:

    In the case of culture, the analog of kinship is very hard to estimate. Having two parents with equal genetic contribution makes the calculation of relatedness easy. In cultural transmission, one, two, a few, or many people in your social network are possible sources of culture. People may use different parts of their network for different cultural domains. No one has proposed a way to estimate cultural relatedness in the face of such problems.

    I have previously worked through this objection in my article on cultural kin selection - in the section titled "memetic relatedness". To recap: it is not true that no one has proposed a way to measure cultural relatedness. Also, relatedness between two humans is one problem, and relatedness between two artifacts or two messages are different problems. The latter problems are significantly more tractable. Cultural information spends some of its time inside brains and some of its time moving between brains - and during these "external transmission" phases, it is often much easier to quantify it.

    It is often harder to measure relatedness in cultural evolution - due to the lack of meiosis. However, this is not a show-stopping problem. Not all creatures in the organic realm feature meiosis in the first place - yet they still have relatives and must allocate resources between themselves and their offspring and parents. The theories associated with kin selection still apply in these cases.

    Cultural relatedness is often easy to calculate. For example, Alice's dollar bill is related by around 100% to Bob's dollar bill, and around 0% to Charlie's Japanese yen. Also, having some relatednesses that are difficult to quantify is not a problem unique to cultural evolution. For example, in organic evolution, it isn't easy to measure the relatedness to two Portugese man o 'war individuals. The fact that they are a symbiotic conglomerate is a complication - but not a show stopping problem.

  3. Maximization of inclusive fitness may not apply "commonly"

    In 2014, Dan Sperber (and coauthors) wrote:

    How deep is the analogy between biological and cultural evolution? Memetics assumes that it is deep indeed; that the main relevant details of the biological case have direct equivalents in the cultural case, such that there is, for example, a cultural phenotype, which achieves a certain level of (inclusive) fitness, which will in turn determine the phenotype’s relative success in the population.
    This is good so far, though I would identify this as a conclusion from many decades of observations - rather than an "assumption". The authors go on to say:

    Darwinian selection leads to the maximization of inclusive fitness, and this explains the appearance of design in the natural world. Is there an analogous result for cultural attraction? As selection is a special case of attraction, design is possible and in some cases explicable in standard Darwinian terms. Having said that, such explanations will not apply generally, and may not even apply commonly.

    The concept of "inclusive fitness" is a simplified model of kin selection which no-one believes applies generally. However, kin selection is a very generally-applicable idea - it is a consequence of natural selection itself in structured populations.

    As for the generality of Darwinism itself - it all depends on what you mean by the term. I think most accept that evolutionary theory has moved on a bit since Darwin's era - with the incorporation of symbiosis, game theory and an understanding of self-organizing systems. However, many still use the term "Darwinism" for the resulting evolutionary theory - as a way of giving Darwin credit for coming up with the basic idea in the first place. Ultimately, this is a terminological issue.

    Personally, I don't like Sperber's various terminology proposals. In fact, I think that they suck. "Attraction" is a basic concept in dynamical systems theory. If you want to redefine it, you had better have a good case. Sperber doesn't present such a case; he doesn't have one. Overloading the term with multiple similar meanings is not an attractive option.

The criticisms of kin selection itself deserve a mention here. Group selection advocates have long been critical of kin selection - arguing that kinship is only one of many ways in which organisms can come to share features, that group selection is more general, that inclusive fitness is a awkward, artifical concept, that kin selection is too hard to apply - and so on.

In some cases widespread criticism from the scientific community pointing out that some of the more extreme critics are plainly off their rockers has helped with some of this.

Widespread recognition that kin selection and group selection are broadly equivalent concepts and represent different perspectives on the same kind of phenomena should help to damp down some more of these criticisms.

However, kin selection has had its flaws. The widespread failure to apply cultural kin selection is one of these. This failure is explicitly mentioned by some critics - e.g. here. However, that is not so much a problem with kin selection, as it is a problem with the scientific failure to get to grips with cultural evolution. Anthropologists - whose job largely involves studying human culture - are mostly-living in a pre-Darwinism timewarp - in which evolutionary theory is not applied to their subject matter. The way to deal with this is not to use kin selection less, but to use cultural kin selection more.

While kin selection is not without issues, these seem minor into comparison with the problems with group selection. Group selection seems to be a fountain of junk science. I think it should come with clear health warnings - and, generally speaking, it does do so.

Anyway, this probably isn't the best place to review the whole kin selection vs group selection debate. I do have another blog where that is one of the main topics.

Kin selection has been a tremendously useful and productive tool in the biological sciences, and there is absolutely no reason why it can't be similarly useful and productive in cultural evolution - and in the social sciences generally. At this stage, scientists just need to pull their fingers out and start applying it. Hopefully, my reviews of the topic have indicated the abundance of low-hanging fruit in this area.

Sunday, 28 September 2014

Tim Tyler: Cultural kin selection

Transcript:

Hi. I'm Tim Tyler - and this is a video about cultural kin selection.

This is a big and important topic which must be condensed for this kind of format - so this is a "firehose" presentation on the topic.

Nepotism is a common phenomena in nature. It has long been understood that evolutionary theory could help to explain why organisms help their relatives. However it wasn't until the 1960s that the process responsible for nepotism was formally modelled.

William Hamilton visualized the germ line of organisms as being broken up into many genes. Each gene is surrounded by many copies of itself in its relatives. It then becomes possible to ask what behaviour the gene could promote that would help the swarm of genes to propagate itself. The answer indicates that there are circumstances under which genes can favour transferring resources to other existing copies of themselves at the expense of their own direct descendants.

The theory that quantifies and explains this phenomenon is known to biologists as "kin selection".

It is a commonplace observation that cultural similarity also results in cooperative behaviour. Empirically, there's a correlation between the memes that people share and how likely they are to cooperate with one another. Memes resulting in observable markers seem particularly significant - so the uniforms worn by the military, nurses, religious orders and corporate workers are especially closely associated with cooperative behaviour. The most conventional explanation for this is known as "fictive kinship". The idea is that shared uniforms stimulate mechanisms evolved to deal with kinship at the level of DNA genes. The kinship involved is not real blood kinship, but rather has been faked by leaders of these groups for their own ends - thus the term "fictive kinship".

However, another explanation invokes cultural kinship. The theory of kin selection is not confined to DNA genes. It can equally be applied to memes. Shared memes often result in cooperation in the same way that shared genes do. Like DNA fragments, memes are frequently surrounded by a swarm of copies of themselves. Again, it is possible to ask what behaviour promoted by the meme would serve to promote the propagation of the swarm of copies surrounding it. Again the answer indicates that memes will sometimes sacrifice themselves to promote the propagation of other copies of themselves. The theory that explains this is called "cultural kin selection" - and that is what this video is about.

Cultural kinship helps to explain why nurses wear similar uniforms to each other and cooperate with one another. Shared memes help to explain explains why your computer and your printer peacefully cooperate to print documents. Nuns form cultural "sisterhoods" and monks form cultural "brotherhoods". Their lives are often dominated by the memes they share, and their mission in life is typically to spread these memes to others. Patriotism memes illustrate that memes can sacrifice themselves if it helps copies of the same meme in others to survive. Cultural kinship is an essential tool for understanding how memes propagate the modern world.

In the organic realm close kinship sometimes results in eusociality - where a fertile queen is surrounded by multiple sterile workers. We see the same phenomenon in culture - banks are surrounded by millions of identical coins and bills. These are not themselves copied. Indeed there are cultural adaptations which actively prevent counterfeit copies from being made. The function of these multiple identical cultural entities is to divert resources to their cultural parents in the bank. Another familiar case involves digital books. these exist in multiple identical copies. However most of the copies themselves are not fertile. Digital rights management and legal threats are used to try and prevent them from being copied.

Sterile worker forms are one of the tell-tale signatures of kin selection. The other one is self-sacrifice. Memes that spread despite apparently aiding their personal destruction could be being spread via cultural kin selection. Patriotism memes and suicide bomber memes are possible examples.

Kin selection is famously associated with Hamilton's rule. To briefly recap, Hamilton's rule measures the cost to a donor and the benefit of a recipient associated with a behaviour and the relatedness between the actors. It then asserts that the behaviour can be favoured by kin selection if the benefit is greater than the cost multiplied by the relatedness. This simplified model of kin selection has proved to be quite useful in the organic domain. However its utility depends partly on the ease of measuring relatedness. In the organic realm, there's a simple approximation that can be used: parents are related to offspring by one half, cousins by one eighth - and so forth. Ultimately these fractions come from meiosis. However, there's not really a direct equivalent of meiosis in cultural evolution - which makes it harder to apply Hamilton's rule. Humans don't share half their memes with their parents and one eighth of their memes with their cousins. However they do typically share more memes with their parents than with their cousins. If you consider the topic of relatedness between artifacts, measuring relatedness often becomes easier - because it is easier to measure memes in artifacts than it is in brains.

It has long been understood by anthropologists that "cultural kinship" exists in humans. Humans treat all kinds of people who are not blood relatives as though they are honorary family members. Churches in particular are full of father, mother, brother and sister relationships which do not reflect any form of blood-based kinship. However, most anthropologists have historically had a weak understanding of evolution - and have reacted with hostility to the efforts of biologists to enter their territory.Many anthropologists seem to associate evolutionary theory with racism and eugenics. Cultural kinship has been regarded within anthropology as evidence that Darwinian evolutionary theory applies only weakly to human behaviour - and that cultural forces are more important. This wilful ignorance of evolution meant that they failed to find a coherent theoretical foundation that would account for their observations.

Cultural kin selection casts new light on this topic. On the one hand it shows that the anthropologists were correct to emphasize the significance of cultural kinship. However, on the other hand, it also shows that the evolutionists were right on target with their Darwinism. Cultural kin selection neatly explains the importance of cultural kinship in humans from within an evolutionary framework that includes the concept of shared memes.

Lastly, cultural kinship offers an intriguing glimpse of scientific history repeating itself. In the 1960s, group selection was a popular theory - before kin selection displaced it. Now, 50 years later, cultural group selection is a popular theory. However, kin selection is much better than group selection. It puts an entirely appropriate emphasis on the significance of close kinship, it more strongly encourages quantification and is less strongly associated with junk science. Group selection has proven itself to be a confusing and misleading tool for understanding essentially the same set of phenomena that kin selection explains. Consequently, the same dynamics that we saw in the 1960s are now evident again. A similar sequence of events seems to be playing itself out with cultural group selection and cultural kin selection. This case of history repeating itself in science gives us an interesting opportunity to quantify the scientific lag that cultural evolutionary theory suffers from. By this metric, it's about 50 years behind mainstream evolutionary theory.

There's a lot more to say about this topic - far more than can possibly fit into this video. Search online for "cultural kin selection" for much more information about this subject area.

Enjoy,

Alan Bennett's "evolution revolution"

If you search for "evoluton revoluton" and one of the things that comes up these days is Alan Bennett's book, titled:

Evolution Revolution: Evolution is True. Darwin is Wrong. This Changes Everything.

This is apparently a book about evo-devo and complexity theory.

I would give "evo-devo" 1/10 for its revolutionary qualities. Complexity theory gets a 6/10 from me on this scale - with the proviso that the revolution dates back to the 1980s. I was taught it at university, and it's been orthodoxy for decades now.

The blurb for this book claims that: "Evolution is simply change over time". That is one definition - but it isn't a definition that makes it a scientific theory. The point of Darwinism was that it made predictions and was refutable. The idea that "evolution is simply change over time" makes "evolution" into an unscientific concept.

I skimmed the book. The contents are of poor quality. It offers a revisionist history of Darwinism. This is a conspiracy theorists book about evolutionary theory. That's unfortunate. I like the "evoluton revoluton" meme. I don't like seeing it being given a bad name in this way.

Oh well, at least Alan Bennet's book is better than Spetner and Shapiro's The Evolution Revolution. That one's a creationist tract!

Let "memetic fields" lie

I read an article about memetic fields today. There seems to be quite a bit of material about "memetic fields" on the internet. The author of the article linked memetic fields to the morphic fields of Rupert Sheldrake - saying: "Memetic fields are the mental equivalent of morphic fields". That seems to be qute appropriate to me: both concepts are junk science.

That's not to say that memes don't sometimes have associated "fields" of influence. For example, one might generalize the concept of a "reality distortion field" to cover all kinds of memetic influence. The "reality distortion field" that surrounds some cult leaders is a potentially-useful concept that could potentially be quantified and given a scientific basis.

However, the biggest problem with memetic fields is that memetics isn't ready for them yet. Maybe if memetics was decades-old orthodoxy, we could consider the idea of some Sheldrake-free memetic fields with a straight face. However that isn't the current situation - and "memetic fields" just sound like too much of a joke at the moment. The term "field" sounds like it comes from physics - and a "memetic field" conjours up some kind of metaphysical emanations from memes. Just the sort of thing that Rupert Sheldrake would love.

I think we should skip the "memetic field" concept for now. It seems like just the kind of fringe science that could potentially give memetics a bad name.

Cultural evolution + group selection = a disaster in the making

Cultural evolution has fought for acceptance for over a century - against fierce opposition from anthropologists, philosophers - and even some evolutionary biologists.

Now, as the penny shows signs of finally starting to drop, some proponents of cultural evolution seem to have got the idea that it is a good move to link the theory to another controversial theory: group selection.

I think this is likely to be a disaster for the public understanding of science. Such a link will cause confusion for lay scientists attempting to understand the theory. It is likely to result in delays is the adoption of cultural evolution. It is also likely to result in misapplications of the theory of cultural evolution.

Linking one controversial theory to another one just risks compounding confusion - and let's face it, cultural evolution is a much more important than a methodological squabble about what accounting method to use in which organisms share heritable information. Modern versions of kin selection and group selection don't even make different predictions. Scientifically speaking, the issue is a bit of a storm in a teacup.

About the only possible favourable outcome I can see is that the controversy associated with group selection might add to the eyeballs scrutinizing cultural evolution. However, group selection is a dodgy theory which adds no new predictions to our existing understanding of science - and it has a long association with junk science - due to it being systematically applied to the cases where kin selection doesn't obviously work.

I think that a much bigger risk is that cultural evolution will be tarred by its association with group selection. Exhibit A for this is the 2012 "Stephen Pinker" controversy. Stephen Pinker is obviously a smart cookie - but he doesn't understand cultural evolution or group selection. However he does know enough about group selection to realize that it is dodgy. Richard Dawkins described it as "A Cumbersome, Time-Wasting Distraction". Not "wrong" - but not very good either.

Anyway, I wish that cultural evolution enthusiasts would put group selection down. They adopted it in an atmosphere of confusion - without a good understanding why group selection was in the dog house. For example, Henrich (2004) wrote in his defense of using the "group selection" terminology:

Concerns and confusions related to Wynne-Edwards (1962) work of over 40 years ago should, in my view, be relegated to history books

However - alas - it isn't as easy as that for group selection to clean up its act. Group selection was driven into the fringes of science by kin selection. It is consistently applied by advocates to cases where relatedness is low - and so the theory doesn't work. It is systematically not applied to cases where relatedness is high - and it is obvious to everyone that "kin selection" did it.

Given group selection's ongoing association with junk science it is just the sort of thing we don't want linked to cultural evolution. Cultural evolution faces strong resistance from within anthropology. One of the many complaints is that those seeking to biologize culture are using naive biological theories, and are doing it wrong - with the potentially significant costs associated with applying these theories to humans. Of course this is a pretty feeble excuse for rejecting Darwinism entirely - but looking at Wilson-style sociobiology, they were partly right - the treatment of culture by these theorists was hopeless. Looking at modern evolutionary psychology they are partly right again - the treatment of culture by these theorists is equally hopeless. Only memetics (and similar theories) take cultural variation seriously as an evolutionary phenomenon - and so has a hope of eventually being accepted by anthropologists. Tying cultural evolution to group selection just creates another opportunity for anthropologists to reject it as "bad science". It's surely a bad strategy which will only hold the field back. Forget about group selection. It's completely unnecessary - and it will just create endless confusion - as it has been doing now for decades. Surely that is the last thing we all want.

Saturday, 27 September 2014

Misrepresentation of kin selection by group selection advocates

Group selection enthusiasts have repeatedly argued that: kin selection can only explain cooperation between close relatives; that humans cooperate in groups in which the humans are not closely related. Since kin selection can't have been responsible, group selection is needed.

This argument has been made innumerable times. It is completely mistaken. Boyd and Richerson made this argument in Not By Genes Alone. Today, we will look at Joe Henrich's expression of this argument in the 2004 paper Cultural group selection, coevolutionary processes and large-scale cooperation. The argument can be found in section 3.2. Joe writes:

Kin-based mechanisms should be designed to focus benefits only on close relatives, and thus kin selection does not help us to solve the problem of cooperation among large groups of unrelated individuals unless our kin-psychology is making a lot of big mistakes by confusing large numbers of non-relatives and strangers with close relatives.

Cultural kin selection is based on shared memes - not shared genes. Cooperation between strangers in military, religious and organizational settings is not a mistake from the point of view of the memes involved. They are recognizing their kin and directing resources towards their kin accordingly.

From the point of view of the genes of the human host the resource allocation does look like more of a mistake. Or rather: it benefits some humans at the expense of others. The genes in the factory bosses no doubt benefit if their workers behave like sisters in an ant nest - and cooperate for the common good. However the genes in the factory workers are probably not doing so well. The workers probably wouldn't wear the blue suits unless they were made to do so - and might treat their co-workers worse as a result. In short they are victims of manipulation who put up with the situation because they are wage slaves who can't find better jobs.

In other cases, the uniform wearers seem to don their robes enthusiastically. Sometimes, religions folk and tribe members seem to love the garb that makes them all appear as though they are brothers and sisters. It seems pretty speculative to argue that their DNA benefits from this - but you can imagine cases where the interests of the memes involved and the interests of the host DNA are more closely aligned. In such cases, cultural kin selection can be invoked to explain the cooperation that results - without the situation necessarily being a "big mistake" from the perspective of the host DNA.

In the paper, Joe continues:

This version of the “big mistake hypothesis” (Boyd and Richerson, 2002a) suggests that, because our psychology supposedly evolved in small groups with high degrees of interrelatedness, kin selection (along with reciprocity, see next section) favored a psychology in humans that is designed to generously bestow benefits on members of their groups. According to this idea, natural selection apparently neglected to provide humans with the ability to distinguish kin and long-term reciprocators from anonymous strangers in ephemeral interactions. Thus, in the novel world of large-scale, complex societies, this once adaptive psychological propensity misfires, giving us large-scale cooperation (Tooby and Cosmides, 1989).

That hypothesis might explain why we don't have better defenses against kinship-related manipulation. However it simply isn't the main kinship-based explanation of why humans are so cooperative! Humans mostly cooperate with other humans which they share memes with because they are manipulated into doing so - via cultural kin selection. The manipulation is typically mediated by memes, but it often serves the interests of the genes of other humans. For example, the politicians and generals spread the patriotism memes - but it's the infantrymen that are killed by them. It isn't a "big mistake" for the memes involved - or for the humans that benefit from the manipulation.

Joe criticizes this so-called "big mistake hypothesis", apparently writes off kin selection and then goes on to advocate group selection for much of the rest of the paper. To his credit, Joe does actually acknowledge the equivalence of kin selection and group selection in this paper (section 4.3). However, his treatment of kin selection seems shoddy to me.

If you want to reject decades of work on kin selection, and advocate an alternative approach, IMO, you should first understand how to apply the standard approach and then go on to explain why your approach is better. In the case of cultural evolution, this involves kin selection applied to cultural variation. IMO, Joe Henrich fails at this project on the first hurdle, by apparently not understanding how to apply the main rival theory: kin selection. This seems like a weak position to launch an alternative approach from.

The modern wave of group selection in the social sciences is built on shoddy foundations like these. Those involved didn't properly understand how to apply kin selection to memes. They thought that kin selection didn't work - for all the wrong reasons. We can now see that they were mistaken. I think that the next issue is how best to clean up the mess they have created.

Friday, 26 September 2014

Getting what makes cultural evolution different wrong

Many students of cultural evolution seem to have an idea about the thing that makes cultural evolution different. In today's paper from 2009 - by Strimling, Enquist and Eriksson - it is the ability of culture to be rejected and reacquired that makes cultural evolution different. In their words:

Although genetic information is acquired only once, cultural information can be both abandoned and reacquired during an individual's lifetime. Therefore, cultural evolution will be determined not only by cultural traits' ability to spread but also by how good they are at sticking with an individual; however, the evolutionary consequences of this aspect of culture have not previously been explored.

The problem here is that this is totally mistaken. Genetic information - information in DNA - can also be abandoned and reacquired during an individual's lifetime. It is common for individuals to be infected with DNA-based pathogens on multiple occasions. Immunity doesn't always last - and often vaccinations need to be regularly repeated. Many parasites can attack the same host many times throughout that host's lifespan. Cold and flu viruses are familiar examples. For pathogens, success often depends on how good they are at sticking with their hosts. This is true for DNA-based pathogens - as well as cultural ones.

My estimate is that: 9 times out of 10 when academics play the game of picking the thing that makes cultural evolution different, they come up with answers that are just wrong. The differences between cultural and DNA-based evolution remain widely exaggerated. That is not to say that cultural evolution and organic evolution are exactly the same - just that wide-reuse of principles from the organic realm is possible. Often differences between the realms turn out to be quantitative - rather than qualitative.

Failure to appreciate the similarities between the realms leads to a failure to reuse existing work - and to pointlessly reinventing the wheel. A failure to appreciate the similarities between cultural and organic evolution is one of the most persistent problems for the field. Most scientists don't understand the similarities at all. Only a small percentage have got as far as understanding that both realms obey Darwinian rules.

You might think that this would lead to academics flaunting their understanding of the similarities - to demonstrate that they understand the topic. However, more often than not the temptation associated with detecting some difference - and then developing a theory about it - seems to be too powerful.