Friday, 6 May 2016

Natural reward and natural punishment

The concept of natural selection part of the core of Darwinian evolutionary theory. However in my opinion, it has become muddied by definitional issues. One issue is the term has come to cover a mixture of processes. It covers both death and reproduction. Another is that some biologists decided they wanted to use the definition of natural selection to distinguish between changes likely to produce adaptation and those likely to destroy adaptations - creating a distinction between selection and drift. I'm not too happy about the results of that effort.

I've previously argued for a conceptual breakdown of natural selection into components representing death and reproduction: natural production and natural elimination. The rest of this post describes some orthogonal concepts.

The term "selection" commonly refers to a choice between alternatives - and the term "natural selection" was coined to indicate that the chooser didn't have to be a breeder, or even an agent: nature could choose. However, IMO, things went rather downhill for natural selection after that. After a while, biologists started to use the term "subset selection" to refer to this simple choosing but they decided that this wasn't much use when considering how a sexual population produced the next generation, since that process also involved transformational changes. The conception of selection was enlarged to handle this more complicated case. That was, I think a big mistake.

Scientists outside biology have another word for "subset selection". They call it "filtering". Filtering is an important process which explains a lot about adaptation in nature. Filtering applies to organisms when they die. Filters may also be applied while choosing mates, or during sperm competition. However, though filtering is an important concept, it doesn't explain everything.

In computer science, filtering is often combined with sorting. Sorting is a common and important process in nature. Rocks are sorted on beaches and molecules are sorted in the atmosphere. I think we can get some clarity back by using the terms "natural filtering" and "natural sorting" instead of "natural selection". I have previously written a whole article about natural sorting.

Unfortunately, sometimes explanations of natural phenomena in terms of filtering and sorting can also become contrived. One problem is that filtering is a binary process: either items make it through the filter or they don't. Filtering is a reasonable metaphor for life or death situations. However it seems less applicable to other aspects of reproductive success. Offspring counts are still somewhat discrete, and it could be argued that they consist of a series of selection events. Resource acquisition can be treated in the same way: either an item of resources is obtained or it isn't. However, here it looks as though we are approximating a continuous function with a series of discrete steps. That kind-of works - but sometimes, it is just contrived and pointless: shoehorning the phenomena into the model.

When phenomena appear continuous, using a continuous model makes sense. My proposal for a continuous modeling framework involves the common concepts of "reward" and "punishment". The idea is that events can have positive or negative on fitness. Positive impacts are rewards and negative impacts are punishments. Other consequences of events are deliberately neglected - for the sake of keeping things simple. As with natural selection, we can have agent-free versions: natural reward and natural punishment.

Reward and punishment are common consequences of actions by agents. However here it is important to remember that natural rewards and natural punishments may happen without regard to the agents previous actions. There need not be any attempt reinforcing of behaviour going on. Nature may be capricious.

In standard evolutionary theory, natural reward and natural punishment are currently most frequently referred to as favorable and unfavorable selection pressures. What I'm proposing here are new names for these existing concepts.

Reward and punishment are concepts from psychology. This is one of the expected application domains. Rewards lead to reinforcement and reproductive success of patterns af various levels in the brain, from synapses to axon firing patterns. Similarly punishment results in weakening and destruction of such patterns. In other words, use of these terms isn't intended as a metaphor, reward and punishment in psychology would be a straightforwards applications of these evolutionary concepts.

Sunday, 24 April 2016

Cultural evolution and Weismann's barrier

In case anyone needs a recap, August Weismann was the guy who cut the tails off of rats. He concluded that a barrier prevented somatic cells from contribution to evolution - now known as the Weismann barrier. The Weismann barrier is a real phenomenon, but people vary on how permeable they think the Weismann barrier is.

There's a corresponding barrier in cultural evolution. Cakes contribute to recipes, but mainly through selection. Anywhere where reverse engineering is complex and difficult, something like the cultural equivalent of the Weismann barrier comes into play. It is hard to dispute the idea that there is less of a barrier in the cultural domain, though. The difference between the domains is partly because there is more reverse engineering in cultural evolution. Genetic engineers can reverse engineer designs originally coded in DNA as well, but for various reasons, they rarely bother. There's plenty of secret computer software in the world, but only a small number of secret genomes. So, people are forced to reverse engineer software from web sites, while few are forced to reverse engineer gene sequences from organic phenotypes.

It's important to recognize that Weismann's barrier is also pretty seriously compromised even if you ignore cultural transmission. As I explained in my article on Lamarckian inheritance in cultural evolution:

Some acquired characteristics are inherited while others are not. If Weismann had chosen a different trait - for example, stress - he might well have drawn the opposite conclusion.

Another problem for Weismann's barrier is genetic engineering. These days a scientist can transfer whatever information they like into the genome. Acquired characteristics, information from somatic cells, detailed sequence information, genes from other species, prime numbers - whatever they like, really. The permeability of Weismann's barrier is increasing as time passes and biotechnology improves.

Tuesday, 19 April 2016

Matt Ridley - Evolution of Everything book videos

Here's Matt talking at Google:

Matt talks explicitly about memes 40 minutes in - raising the objection that memes are particulate, while culture doesn't have to be. He describes memes as being "a bit restrictive" and says: "I feel it's moved on since then".

I regard these objections as bogus ones. Memes represent heritable information in cultural evolution, just as genes represent heritable information in the organic realm. The idea that memes (and genes for that matter) are too 'particulate' is to do with the molecular biology definition of the 'gene' - not the evolutionary definition of the gene. Remember that genes are not sections of nucleic-acid.

Memes (and genes) are 'particulate' in the sense that they are informational - and so can be divided up as much as you like. Information can be subdivided into particulate bits and sent down cables. That's just a fact, and it isn't specific to memetics: most other theories of cultural evolution assume a basis in information theory, focus their attention on heritable cultural information and use some kind of meme synonym.

Here are a couple of other recent videos from Matt on the same topic:

Friday, 15 April 2016

Shared interests of unrelated symbionts

Unrelated symbionts tend to affect the host in similar ways. For example, many symbionts tend to make hosts leak bodily fluids - through bleeding, diarrhea, coughing, sneezing and pimples. Similarly, many stimulate interactions between hosts to facilitate their own reproduction - with rabies, toxoplasmosis and malaria being some of the best-known examples.

Can we make the same sorts of statements about cultural symbionts? I think so. Most of the rest of this post will give examples. Speaking and writing skill skills are a common pathway into the future for many memes. Speaking to large audiences is especially desirable. Teaching skills are particularly useful to many memes.

Like their organic counterparts, cultural creatures depend on contact between their hosts for their transmission - and so many of them tend to promote frequent, peaceful host interactions.

Another area involves resource allocation. As with organic parasites, many cultural parasites benefit from reducing the fertility of their hosts. Resources spent on host reproduction are resources not available for parasite reproduction. There's a considerable evidence that shows that memes do tend to have this effect.

Symbionts are also interested in host lifespan. They tend to follow one of two strategies. One involves turning the knob that controls the reproduction-maintenance axis towards maintenance - a living host is typically more useful to symbionts than host offspring are. This tends to increase host lifespan. The other strategy is to burn through host resources and convert them into symbiont offspring as fast as possible. Ebola would be an example of this strategy. This sort of thing tends to decrease host lifespan. The second strategy is often especially harmful to the host.

The whole phenomenon of shared symbiont interests is, I think, something useful to be aware of. If many agents are attempting to influence you in the same direction, that increases the chances of their collective manipulations being successful. Some people might want to take steps to compensate.

Saturday, 9 April 2016

Restraint and confinement

This post is about a topic in symbiology - symbiont restraint of host. The idea applies to both organic and cultural symbionts, so I will attempt a presentation in general terms and then give examples from both domains.

Symbionts have their own optimization targets, involving maximizing the number of their offspring. These typically conflict with the optimization target of their hosts. So the symbionts typically manipulate their host into acting against its own interests. There are many ways of performing such manipulation - but this page is about one type of manipulation: preventing the host from acting.

Restraint is one of the simplest types of manipulation. Restraint has most of the advantages of destruction over construction. Just as it is easier to destroy than create, it is easier for symbionts to eliminate host behavior than it is to create new behaviors.

High on the list of behaviors that it often pays for symbionts to reduce involves making host babies. Babies consume time and resources, that might otherwise be spent on symbiont reproduction.

In the organic realm, many parasites sterilize their hosts, or reduce their fertility. Among humans, sexually transmitted infections are a common source of infertility. Chlamydia and gonorrhea are common culprits. If you have babies, you are likely to have less sex with fewer partners. Keeping you childless is pretty clearly in the interest of STDs.

Cultural symbionts reduce fertility in much the same way. Degree of female education, is strongly negatively correlated with fertility. Cross-country comparisons show that the most educated countries have the lowest fertility. Family planning and contraceptive memes are implicated. Thanks to technological memes, many choose to have sex without paying the childcare costs.

Many symbionts share the same goals regarding preventing hosts from engaging in resource-intensive activities that further their own ends. Their influences tend to add up. The result is a bit of a war between a host and its symbonts. The symbionts don't all pull in the same direction, but their pulls are correlated in ways that restrain host activities. Even mutualist symbionts can contribute to the restraint.

The idea of restraint by symbionts is similar to Mark Changizi's proposal that memes harness human hosts. Mark's harnesses also restrain their hosts. They also typically result in resource transfers from host to symbiont. The idea here is that no harness needs to be involved. Merely caging or confining the host can be sufficient to effect such resource transfers.

Restraint of host resource expenditure on host offspring isn't the only common interest of host symbionts. Many symbionts are also interested in promoting host social behavior, for example.

This idea provides theoretical support for ideas in folk memetics about meme jails, meme bubbles and people being imprisoned by their own memes.

Friday, 8 April 2016

Templeton foundation gets into cultural evolution

The John Templeton Foundation has been funding research into cultural evolution for a while now. Past grant recipients include:

Recent news says Kevin Laland, Andrew Whiten, Richard Watson and others have landed a 8 million dollar Templeton Foundation grant to explore their proposed extended evolutionary synthesis - which includes 'extended inheritance' - one of the topics frequently discussed on this blog.

It's sad times for the field if researchers are reduced to taking Templeton Foundation money. Scientists getting involved with the Templeton Foundation seems as though it is generally bad news. It legitimizes the Foundation's theistic efforts - and tends to produce junk science, like the 2010 Templeton-funded Nowak, Wilson and Tarnita debacle. Of course scientists can choose to accept any source of grant money, but perhaps at the expense of their reputations.

Here's commentary from David Sloane Wilson and Jerry Coyne and Larry Moran.

Evolutionary foresight goes mainstream

The mainstream seems to be finally waking up to some of the idea I expressed in 2008 in my "evolution sees" essay. In particular, Richard Watson, Eörs Szathmáry and others have recently been arguing that evolution can learn. Not just with trial-and-error learning, but with real connectionist learning. Here are some of their papers:

Though their conclusions seem similar to mine, their argument looks a bit different. They suggest that connectionist learning in ecological populations might be important. If that happens without animal nervous systems, that would be new and interesting. Even without this idea of theirs, my argument for the evolutionary significance of connectionism still stands.

Sunday, 27 March 2016

On NLP

Looking at what the internet thinks about NLP (Neuro-linguistic programming) suggests that it has decided that NLP is pseudoscience.

NLP was a bit pretentious - by putting the term "neuro" in its name - but we could have lived with that. It is true that humans are programmable animals - and that they can be programmed using language. This is fairly obviously a topic for scientific study.

It seems a bit unfortunate that NLP didn't make more headway. If NLP fades away there will be a bit of a void in the niche it once occupied. I think we should probably hang on to the "linguistic programming" part. I can't think of any more appropriate terminology. We do have the well-established term "suggestion" - but "linguistic programming" is specifically to do with language, and not all "linguistic programming" comes in the form of suggestions.

The problem I see with "linguistic programming" is that you can program both brains and computers with language - but these are pretty different topics, so there is not all that much need for an umbrella term.

The most obvious alternative to this path that I see is to try and hang on to NLP - and turn it into a respectable topic. I'm sure that that path will have some advocates. I'm not sure at this stage that this plan would be effective.

Saturday, 26 March 2016

The cultural nose hypothesis

As Richard Dawkins put it in 1976:

Most of what is unusual about man can be summed up in one word: `culture'.

The human nose is an unusual feature of humans. Most apes have flat noses. Does culture explain the human nose? If so, how?

Several hypotheses come to mind. One proposes that big noses come with pronounced brow ridges which act to defend the eyes against being punched in the face - something which humans are much better at than our cousins. Gene-meme coevolution comes in here since accurate punching is tied in with rock throwing skill - which is a culturally-transmitted hunting technique.

Another hypothesis is that the nose acts as an air lock. The nostrils point down, preventing water from entering the nose during common swimming techniques. Swimming is a culturally-transmitted trait. Humans are much more water-friendly than other apes. Water is potentially a strong source of selection, since water entering the lungs can be fatal. Elaine Morgan is probably the best known proponent of this idea. She covers it in her book The Scars of Evolution, for example.

Another hypothesis is sexual selection. Whenever some part of the body grows to an unusual size, sexual selection ought to be on the table as a possible explanation. The nose of the proboscis monkey illustrates this possibility.

Lastly, northerners tend to have bigger noses than equatorial folk - suggesting that the nose acts as a heat exchange and represents one of many adaptations to living in a cold climate - somethings humans can do largely due to cultural transmission.

I tend to favor the 'airlock' hypothesis. The heat-exchange hypothesis predicts that most Africans should have chimp-like flat noses - which they evidently do not. The idea of a defensive barrier would suggest that males would have bigger noses than women. Similarly, sexual selection typically affects traits differently in the different sexes. There is some nasal sexual dimorphism - but probably not enough for these theories.

I propose here that the 'airlock' hypothesis be promoted as the cultural nose hypothesis.

Thursday, 24 March 2016

Branch tip evolution

I came up with the idea of branch tip evolution in 2012 by thinking about positional inheritance. Probably the simplest way to understand it is by thinking about the evolution of buds on tree branches. Buds reproduce and they undergo selection. The result is often an adaptive fit between the shape of the tree and its environment. For example, some buds may be in shade under a bridge while others may overhang a busy road. Selection affects the growth and reproduction of the buds, resulting in an adaptive fit between the shape of the tree and its environment.

Copying with selection resulting in adaptive fitness are the hallmarks of Darwinism. However this was not a form of Darwinism based on DNA genes. The example holds up even if all the tree buds involved are precisely identical in terms of their DNA.

A kind of Darwinism of branch tips can be useful in explaining a wide range of tree-shaped structures in nature. In the organic realm, there are branches, roots, corals, circulatory systems, respiratory systems, and branching axons and dentrites. Inorganic tree-shaped systems include electrical discharges, propagating cracks, crystal growth, and drainage basins.

Many models of these types of inorganic system take a functional approach to them - for example, saying that drainage basins form efficient structures for rapidly removing water from landscapes - of that they maximize the production of entropy. From an evolutionary perspective, such models are all very well, but they are all to do with adaptive function. Adaptation is part of evolutionary theory - but it also has another side: path dependence, or historical contingency. Evolutionary theory provides a rationale for adopting a functional perspective in the first place, and it also helps to explain cases where there are deviations from what strict functionalism might predict.

While branch tip evolution is an excellent and important model of many physical systems, it has limitations. In real trees, there is cell reproduction within the branches as well as at the branch tips. Also, there are other cases where branch dynamics are important - i.e. when not all the action in the system is taking place at the branch tips. Finally, real branch tips can sometimes shrink as well as grow. In such cases, the analogy between the real tree and a family tree starts to break down. More sophisticated models involving graph evolution may be a better fit for such cases.