Sunday, 31 March 2013

On directed mutations

One argument used against cultural evolution is that culture features "directed mutations" - while in the organic realm, the "direction" of mutations is not associated with positive fitness outcomes.

Here's Massimo making that case:

a cardinal tenet of the Modern Synthesis (and indeed of the original Darwinism) is that mutations — the ultimate source of novelty in evolution — are random with respect to fitness outcomes. It is important to understand this point.

This is indeed an idea associated with the modern synthesis. However:

  • It wasn't part of Darwin's thinking;
  • It is not correct.

Darwin may have called variation "spontaneous," "accidental" and "chance" - but he didn't reach the level of dogmatic assertions on this issue later authors did. His descriptions were generally OK.

Mutations are normally deleterious, and are heavily constrained by natural selection. Selection builds error correction and detection mechanisms. If influences mutational hotspots. It acts on chemical concentrations of intracellular mutagens. It acts on mutagenic DNA sequences - such as LINEs and SINEs. Organic mutations prefer junk DNA to coding regions. They also prefer recently-mutated regions. Both patterns bias mutations in the direction of being less maladaptive than "random" mutations would be. Selection acts on mutation rates in many ways - controlling its rate on a species-by-species basis - and a tissue-by-tissue basis. Mutations hit the old more than the young. They hit somatic tissues more than germ-line cells. They hit redundant organs more than unique ones.

The result of all this is that the most deleterious mutations are eliminated, or fixed - and the remaining ones are closer to neutral. This leads to mutations being less deleterious than they would otherwise have been.

In other words, actual mutations are less deleterious than random mutations would be. Mutations are thus directed in favour of positive outcomes.

Steven Pinker says:

Genetic mutations and recombinations are strictly typographical, twiddling the As, Cs, Ts, and Gs with no foreknowledge of their effects on the organism's interactions with the world.

However, this is just wrong. We know that mutations occur in a manner shaped by natural selection to avoid their most negative consequences, while promoting adaptive outcomes - for example via mutations in the immune system.

What is the response to all of this by supporters of the modern synthesis? It turns out that that they radically shift the goalposts:

A genetic mutation is a matter of chance from the evolutionary perspective – or is a matter of "evolutionary chance" – if and only if it is not specifically caused in an (exclusively) adaptive way by a physico-chemical process in response to environmental conditions.
- Evolutionary Chance Mutation: A Defense of the Modern Synthesis’ Consensus View - Francesca Merlin

So: apparently, these days, mutations are a matter of "evolutionary chance" iff they are adaptive!

I think it is pretty clear that the idea of mutations being random with respect to fitness has been lost. That is too ridiculous an idea for anyone to seriously entertain these days. It is contradicted by too much evidence. Instead the goalposts have been dramatically shifted to mutations not being adaptive - on average. That's a pretty high bar.

I should add that I think that the idea of "evolutionary chance" is a farcical idea. Let's leave the concept of "chance" to statisticians - who are clear what they mean by it.

Jerry Coyne offers a quite different defense:

What we mean by “random” is that mutations occur irregardless of whether they would be good for the organism. That is, the chances of an adaptive mutation occurring is not increased if the environment changes in a way that would favor that mutation. The word “random” does not, to evolutionists, mean that every gene has the same chance of mutating, nor that mutation rates can’t be affected by other things. What it means is that mutation is not somehow adjusted so that good mutations crop up just when they would be advantageous
Here mutations must not only occur "non-randomly" - and even being beneficial is not enough - instead, the chance of beneficial mutations arising must be correlated with environmental fluctuations. Again, this is surely a raising of the bar for what it takes to qualify as a "non-random" mutation.

Where does this leave cultural evolution? The claim that mutations are directed in cultural evolution and are undirected in organic evolution is false. Mutations in both cultural and organic evolution are both directed. Differences in the degree of directedness are best regarded as being quantitative - not qualitative.

The other issue that critics raise is that mutations in cultural evolution are much more strongly directed in cultural evolution compared to organic evolution. However, it turns out that most of these critics are comparing memes with genes - using between-host transmission times to calculate the generation time of the memes in question. They ignore - or maybe just don't understand - the idea that memes often have a multi-stage lifespan - which includes multiple rounds of reproduction, recombination and selection inside the brains of their human hosts.

This isn't a fair comparison. If you are compare mutations with multiple rounds of mutation, recombintion and selection, the no wonder the latter process looks like intelligent design coming out out of nowhere. However, that's a topic for another day.

Saturday, 30 March 2013

What are the real problems with memetics?

I've read a lot of criticisms of memetics - as part of my project to rebut them.

For the most part, the criticisms are not worth too much. Most of the critics don't understand memetics well enough to present competent criticisms - and in many cases they don't seem to be trying properly to find a sympathetic interpretation.

However, I figure that I am in a better position than most critics - in that I know the topic pretty well.

In the spirit of steelmanning: what do I think the real problems are for memetics?

  • Memetics has historically been a theory of the evolution of socially-learned information. However there's also the evolution of individually-learned information to consider. Dividing individual learning from social learning when classifying scientific fields seems suspect. Social learning and individual learning interact deeply, and attempts to divide the two topics seem to face problems. In many respects, it would make more sense to have a field that covered the evolution of all ideas. I've covered this issue previously in my articles on Lemes, The case for private culture, The case for private memes and Individual learning in memetics. Academic students of cultural evolution face the same issue - however few of them show much sign of understanding the need for a theory of the evolution of ideas within minds.

What should be done about this problem? Fairly obviously, the field needs to self-consciously expand to cover the evolution of ideas or concepts. Some authors have already taken this step - e.g. the work of John Lin explicitly deals with the evolution of concepts. We can still have an evolutionary science of social learning - but it should clearly be subsidiary to the science of learning. I still like the idea of expanding our conception of culture to cover individual learning - as a solution to this issue. The definition of "culture" has always been a matter of controversy. While it may seem like a radical redefinition, it makes a lot of sense to me.

The idea that memetics will be boosted by discoveries of how memes are represented within minds may have something to it. Watson and Crick helped the science of genetics establish itself - memetics may experience a similar boost in the future - when the neural representations of memes are better elucidated.

The rise of academic opposition to memetics among students of cultural evolution seems to be an unfortunate phenomenon. I think memeticists should make such opposition look merely stupid. If you work in the field and don't understand memetics, that should be a matter of personal embarrassment - not something to advertise publicly.

I think most of the other problems for memetics are not really technical, but have more to do with marketing.

Daniel Dennet promoting "Breaking the Spell"

Here is Daniel Dennett lecturing in a Washington DC bookstore in 2006 - promoting his book on religion. The memes start 25 minutes in.

Daniel Dennett on evolution, February 2013

Here is Daniel Dennett lecturing in February 2013. The memes start 38 minutes in.

Another - rather similar - video: Dennett and Others on the Evolution of Reasons. Memes are 47 minutes in there.

If cultural evolution is Darwinian, why is it faster?

Massimo Pigliucci recently wrote:

The conclusion that biological and cultural evolution are different also nicely accounts for the fact that cultural evolution is so much more dynamic (it happens much faster) and unpredictable than its biological counterpart. If we think of both as instances of Darwinism that difference becomes more puzzling.

Cultural evolution is indeed a new kind of evolution. However, most modern accounts of the process by scientists working on cultural evolution still classify it as being Darwinian.

The reasons include the fact that Darwin himself recognized cultural evolution - and said that natural selection applied to it - by saying:

The survival or preservation of certain favoured words in the struggle for existence is natural selection.
More specifically, cultural evolution exhibits reproduction, variation, selection and cumulative adaptive evolution - the key hallmarks of Darwinian evolution - according to many authors writing on the topic since the 1970s.

How then are we to account for the recent explosion of evolutionary activity? The skyscrapers, satellites and microprocessors that have suddenly materialised?

I think that the tower of optimisation concept is a useful way of thinking about what is going on. This illustrates the evolution of evolvability - charting evolutionary progress through sex, learning, culture - and towards engineering. Evolution is constantly expanding its the "natural technology" it has accumulated - the know-how like photosynthesis and cellulose that allows more niches to be occupied. Engineering and intelligent design are just the latest additions to a toolbox with a long history - going back into geological time. Nature adding more tools to an existing toolbox which already contains many tools doesn't suddenly stop the evolutionary process from being Darwinian. If you think it does, I recommend reconsidering your classification scheme.

In many respects, the whole issue boils down to whether we should give credit to Darwin for discovering the combined significance of the concepts of reproduction, variation, selection and cumulative adaptive evolution. I think that we should. Evolutionary theory was Darwin's baby. He understood the broad applicability of his idea - including its applicability to human culture. His understanding of evolution was better than that of many evolutionists today, particularly those who - like Massimo and Pinker - are still having a hard time swallowing the concept of cultural evolution.

Tuesday, 26 March 2013

Google trends now covers YouTube searches

Google trends now covers YouTube searches. They have data going back to 2008.

In their blog post announcing the new feature, Google link to a recent viral phenomenon.

The cause seems to be "Goat Edition" remixes. Some of these are pretty funny. Here's a "Taylor Swift" one:

Saturday, 23 March 2013

2012: The year of the meme

I declared 2011 "Year of the meme". However, a bunch of other people seem to have beaten me to proclaiming 2012 to be the "Year of the meme" [1, 3, 3 ].

Looking at the search statistics below, they have a point:

Here are the latest Google Trends results for "meme":



History of "Meme" searches (with news information)

Here are the current Google Trends results for "memes":



History of "Memes" searches (with news information)
The exponential rise of memes seems to have halted. If isn't clear if we have had peak meme.

Was my proclamation ahead of its time? Will 2013 also be the year of the meme?

Update: Merriam-Webster Inc., has announced their "Top Ten Words of 2012". For the first time, "meme" made it onto the list!

Sunday, 17 March 2013

My other blog (Kin Selections)

Some time ago, my study of cultural kin selection (research for my next book) dragged me into the topics of kin and group selection. Rather than post related material here, I started another blog called Kin Selections. There are 23 posts so far. There is some material there related to memetics.

Probably the most significant material there so far are my lists of references for cultural kin selection and tag-based cooperation. This is technical material, but it should allow interested parties get up to speed on the topic before my next book is published.

Saturday, 16 March 2013

Mememolly explains memes

Mememolly returns to explain what (internet) memes are:

DarwinSF

DarwinSF is a self-conscious memetic engineering shop.

They grabbed my attention recently by blogging an article titled Toward a Rigorous Science of Cultural Evolution.

We kind-of have that now, at long last. A least we have rigorous models which capture many of the most important aspects of the dynamics of cultural change.

Anyway, I checked out their site, and found they have a favourite set of memes: global warming. Yes, those are powerful memes to hitchhike on - but, alas, global warming in on my top ten list of bad causes - things that sap humanity's strength withouthproducing much of value.

Anyhow, here's their pitch:Meme Science vs. Global Warming

The video concludes:

Get involved and let's tackle this huge crisis - before it's too late.

<fx: Tim facepalms>

Alien memtic takeover?

Here, an author on the paranoid think tank LessWrong speculates on the A-for-Andromeda scenario of hostile takeover by alien memes.

If intelligent life is sufficiently rare, such messages may well just peter out ineffectively.

However, if not - and instructions for building an interstellar civilization are being sent out by aliens - it seems tremendously unlikely that they will only be tagrgetting only immature civilizations. A message that can improve most civilizations would have many more potential victims and much better spreading power. An alien virus would face an competent immune system. However, an offer of meme-sex would not face such a reaction. So: we should probably be thinking of alien pollen - rather than an alien virus.

The author of the article concludes that:

SETI serch is or useless or dangerous, and should be stopped.

However, that seems like a paranoid conclusion. If aliens are broadcasting their memes, we should absolutely make use of memetic hitchhiking, to add their technological distinctiveness to our own.

Cool image of twitter tribes

Many online cultural evolution researchers love Twitter - because of its open API and public data. Here's a cool image of twitter tribes they have produced.

The researchers grouped together those using similar words in their tweets. That associated news article asks Which Twitter tribe are you?

Wednesday, 13 March 2013

Daniel Dennett: How Darwinian is Cultural Evolution?

The blurb reads:

Dan Dennett giving a talk at the Ecole Normale Supérieure during "Sperber Week," Paris, Dec, 2012.

Dan's next talk is in the UK, titled: Cultural Evolution: from memetic evolution to intelligent design. Video, please!

Dan Sperber responds at the end of the video. He proposes that we call adaptive peaks in the memetic fitness landscape (what he calls cultural attractors) by the name "memes". He says:

Here's a simple solution: a meme is an attractor. That's what it is it's a cultural attractor.
From my perspective, this it a daft suggestion. Memes are things that move around on fitness landscapes. Attractors are peaks on the fitness landscapes themselves. These are very different ideas - not to be confused. Memes may often be found on adaptive peaks, but they can also be found elsewhere on the fitness landscape as well. You need to have both concepts. Combining them into one concept absolutely will not do.

Peaks in fitness landscapes are a commonplace idea in population genetics. For a treatment of them which relates them to memes, see here.

One of Sperber's points is that some cultural information is transformed during copying (in a way that generates attractors that precede selection). However, he doesn't seem to think this happens during copying of DNA - while, in fact, it does. DNA has its own copying distortions, as a result of error-correction gone wrong, malfunctions of the copying machinery and other factors.

Transformations during copying are a type of mutation in genetics and memetics. Memetics, like genetics, has a modular structure that allows different theories of mutation to be used. A typical model of mutations in both domains is that mutations are random. This is, of course, incorrect, but it is a helpful simplification that makes models tractable - and avoids the charge that unrestricted mutations can predict any type of change, thus rendering resulting predictions useless. Use of such simplified models in the face of complex phenomena is absolutely routine for scientists.

Dan Sperber is quite insulting about memetics, claiming that its insights are OK for philosophers, but are inadequate for empirical scientists, who must deal with culture's complexities. Basically, like most meme critics, he doesn't really understand memetics - and so isn't in much of a position to offer intelligent criticisms. What he does say shows that he has a different understanding of the concept of "copying" from the memeticists. For me, the term "copying" has a technical meaning - linked to Shannon's concept of mutual information and the concept of causality. Perhaps the idea needs spelling out for the social scientists. Having said that, Sperber (2000) did a reasonable job of explaining the concept (calling it "replication"): He wrote:

For B to be a replication of A,
  • B must be caused by A (together with background conditions),
  • B must be similar in relevant respects to A, and
  • The process that generates B must obtain the information that makes B similar to A from A.
This doesn't say what "relevant respects" means - and causality isn't always an obvious concept - but, overall, this isn't too bad.

Tuesday, 12 March 2013

Darwinian psychiatry

Williams and Nesse famously called for Darwinian medicine. However we also need Darwinian psychiatry. It is pretty clear that many psychological difficulties are caused by over-reproduction of ideas and memes. Obsessions, paranoia, schizophrenia, stress and depression, all often feature prominent meme overgrowths as either symptoms or causes. Memetic adaptations for reproducing inside minds combine in some individuals with a weak memetic immune system to produce pathological behaviour.

Darwinian medicine has adapted the exorcisms and casting out of evil spirits of primitive peoples into practical techniques that actually evict the invisible invaders responsible for pathology.

However, true Darwinian psychiatry is still in an embryonic state. There are psychological equivalents of antibiotics, vaccines and bleach - but these are often poorly studied and inexpertly deployed.

There has been pioneering work by Hoyle Leigh, but still much remains to be done.

Chris Buskes on the evolution of cultural evolution

Here's a new article by Chris Buskes on the evolution of cultural evolution: Darwinism Extended: A Survey of How the Idea of Cultural Evolution Evolved

This article has some fairly major problems from my perspective. One problem is this:

I will argue that cumulative selection is the distinctive and defining characteristic of Darwinian evolution.
Darwin didn't ever say that. He discovered the copy-variation-selection algorithm behind evolution. It seems insulting to his heritige to confine the term "Darwinian" to the subset of cases where there's cumulative adaptive evolution. Chris's proposal would mean that we would have to rename Universal Darwinism. However, Chris's proposal sucks - I recommend that people ignore it.

Another problem with this article is its memetics FUD. Sure, some people don't understand memetics, but that doesn't mean that nobody does.

The criticisms about replicators and the alleged particulate nature of memes have good answers, but Chris doesn't seem to be aware of this.

Another problematical sentence is:

Of course, nobody denies that the transmission of cultural information differs from the transmission of genetic information, if only because the former process generally does not involve sex.
Huh? Cultural evolution seems to me to involve recombination around as often as organic evolution does.

Chris presents an argument that organic mutations are directed, but he doesn't seem to understand the position that he is arguing against very well. The opponent's don't claim that mutations are entirely random. Showing mutations occur non-randomly seems to be arguing against a straw man. The actual position of critics is that organic mutations are not directed towards higher fitness. This position is indeed incorrect - but Chris fails to mount a coherent argument against it.

The general thrust of Chris's argument - that cultural evolution is less directed than critics say, and organic evolution is more directed than critics say - is essentially correct.

Overall, I don't recommend learning about memetics from Chris. If you don't understand memetics, find people who have a sympathetic understanding of the subject, and learn it from them. There aren't any valid technical criticisms of memetics. It's a perfectly valid and useful set of frameworks, perspectives and terminology for studying cultural evolution with.

Monday, 11 March 2013

Massimo on cultural evolution

Massimo Pigliucci is one of the few remaining critics of memetics who still pops their head up now and again.

In his latest broadside, he provides a neat summary image ->

Firstly culture is biological. It is part of biology which is the study of life. Culture is part of that - as opposed to being inorganic, like most geology. Contrasting "Cultural evolution" and "Biological evolution" is only possible if you don't grasp this.

From the bottom up:

  • Organic evolution does exhibit horizontal and oblique transmission. These terms are standard in epidemiology, and come from the organic realm, not the cultural realm. Cultural evolution students borrowed these terms from epidemiology in the 1980s. Horizontal transmission is the norm in bacteria - which represent most of the individuals and species on the planet. The idea that organic evolution does not exhibit horizontal and oblique transmission is completely wrong. Nor are horizontal and oblique transmission at all rare.

  • Massimo claims organic evolution is "non-intelligent". Yet there is selection by intelligent agents in the organic realm all the time. Large-brained organisms choose who to have babies with, when to fight, and when to run. The idea that organic evolution is "non-intelligent" is completely wrong.

  • Lastly, there's variation. Massimo claims that "a cardinal tenet of the Modern Synthesis (and indeed of the original Darwinism) is that mutations — the ultimate source of novelty in evolution — are random with respect to fitness outcomes". Of course, most mutations are deleterious. However after trying for a sympathetic reading, the claim that mutations are "random" with respect to fitness is outdated neo-Darwinian dogma. Organic mutations prefer junk DNA to coding regions. They also prefer recently-mutated regions. Both patterns bias mutations in the direction of being less maladaptive than "random" mutations would be. Selection acts on mutation rates in many ways - controlling its rate on a species-by-species basis - and a tissue-by-tissue basis. SINEs and SINEs also cause mutations in ways that are strongly subject to selection. Mutation just isn't a phenomenon which is random w.r.t. fitness.

I make that zero out of three. Not a good showing. Only the point about variation remains at all controversial.

Massimo says:

This is the section in which he cites the now classic work of people like Cavalli-Sforza, Feldman and others on gene-culture co-evolution. The thing is, if we are meant to take that (interesting, pioneering) work as a way to theorize about cultural evolution, we are at a dead end. Most of those papers are from the 1970s and ‘80s, with very little having been done since. That approach looks increasingly like what philosopher of science Imre Lakatos famously called a “degenerative” research program, i.e. an approach that seemed once fruitful but that has since ceased to bear fruits.
Unlike Massimo, I am familiar with much of this literature, and my testimony is that he is wrong about this. I've previously graphed papers on memetics.

I checked with Google scholar on "cultural evolution". It shows this growth:

1970s: 27,400
1980s: 79,800
1990s: 372,000
2000s: 1,150,000

Of course most scientific fields are growing, but the field of cultural evolution is exploding - and, yes, some of those papers are doing meme frequency analysis based on population genetics.

In the comments, Massimo repeats one of his more ridiculous objections to cultural evolution:

No, there is a huge difference: what saves the theory of natural selection from being tautological is the existence of a functional ecology of living organisms: we can predict which characteristics of an organism, given a certain environment, are more or less likely to be selected. No such thing is available for memetics. In the latter case all there is to it truly is: the fittest memes survive. Which memes survive? The fittest ones!
Nobody in the field takes this kind of nonsense seriously. I previously destroyed this objection here.

Sunday, 10 March 2013

Reply to Peter Godfrey-Smith on selfish memes

Here's Peter Godfrey-Smith criticizing selfish genes and memes:
Two kinds of agential narrative have a special psychological potency. The first is a paternalist schema. Here we posit a benevolent agent, often a large one, who intends that all is for the best. This category includes various Gods, the Hegelian "World Spirit" in philosophy, and stronger forms of the "Gaia" hypothesis, according to which the whole earth is a living organism. The second schema is a paranoid one. Now we posit hidden agents, often small, pursuing agendas that cross-cut or oppose our own interests. Examples include demonic possession narratives, the sub-personal creatures of Freud's psychology (superego, ego, id), and selfish genes and memes. And while it is true that sometimes there are large and kind agents or small and nefarious ones at work, the psychological appeal of these ideas means that we tend to take up such stories too readily and run with them too far. The account of evolution in terms of "selfish genes" (Dawkins 1976) is a paranoid narrative of this kind. It relegates other entities in evolution, such as whole organisms, to the role of mere "vehicles."

This is a situation where a communicative device or heuristic has been allowed to take on too substantial a role; it becomes a kind of foundational description. Instead, the way to think of gene-level evolutionary processes is like this. Any collection of entities which vary, inherit characteristics in reproduction, and differ in how much they reproduce will evolve by natural selection. These include entities bigger than us, like social groups, entities smaller than us, like cells and genes, and organisms like us. As long as they satisfy the requirements of variation, heredity, and fitness differences, they will behave in a Darwinian way. The recognition that genes have the necessary features – they vary, inherit features in replication, and differing how much they are replicated – is the recognition of one of Darwinian population among others. It is not true that when we find small things doing this, inside us or underneath us, we're finding what it's all about, what it all means, the agents whose plots and programs are behind everything else we see.

I like this passage because it is eloquently put. However, I think we have to label it as misleading.

Richard Dawkins famously argued against individual and group selection because individuals and groups didn't "replicate" - and instead recombined. While there's clearly something to this, we have subsequently learned that this isn't really a convincing argument against all group selection. Wade's flour beetles convincingly showed that group selection and gene selection could peacefully coexist.

Godfrey-Smith is making much the same argument as Dawkins - but the other way around. Like Dawkins he's arguing that group selection and gene selection are incompatible. Peter likes the idea of selection at multiple levels, but thinks that this invalidates gene-level and meme-level selectionism. Dawkins apparently [1] thought that gene-level and meme-level selection invalidated group selection. The truth is more like: selection on memes and genes is one way of looking at things and selection at multiple levels is another. Individual and group-level selection don't disprove gene-level selection - they just show that it isn't the only way of looking at things. However, it was never claimed to be the only way of looking at things in the first place.

Compare memetics with atomism. Ballistics has different principles from atomic physics - and it is useful in cases where atomic physics is not. However, Ballistics doesn't disprove atomic physics. It's just working on a different scale. No violations of atomic physics are involved.

Stories of selfish genes and memes don't deserve to be described as "paranoid narratives". That really is what's going on. Sure: it's not the only way of looking at the world, but it is a valid way of looking at it. Indeed, it's the most complete and comprehensive way of looking at things - though the associated models are not always tractable. If you work at higher levels you miss out on the details.

[1] I realize that Dawkins was probably attempting to verbalise a valid point about how too much recombination often messes up the possibility of adaptations at higher levels.

Update: 2013-09-29: I notice that David Queller has an excellent Godfrey-Smith-smackdown on this topic here. Queller is right.

References