I’ve got two quickish thoughts on cultural evolution, once concerning the concept of cultural beings and the other in my ongoing ‘war’ against the concept of cultural information.
Cultural Beings and Intertextuality
I’ve recently introduced the term “cultural being” to indicate a package or envelope of coordinators (aka a ‘text’) plus the ‘trajectories’ of that package in the minds of all who encountered it. Such misgivings as I still have stem from the fact that it is in fact an odd notion, though it’s not so different from how the concept of ‘the text’ is in fact used in literary criticism. Literary critics also talk about intertextuality, how texts are related to one another.
The fact that Greene’s Pandosto was reworked into Shakespeare’s The Winter’s Tale is thus a fact about the intertextuality of both texts. Shakespeare may have written his text, but he did so after having read Greene’s text and using is as a model for his. The Winter’s Tale is thus, in a sense, a daughter of Pandosto. And most of Shakespeare’s plays are daughters of multiple sources.
The cultural being that is associated with Pandosto would thus extend into Shakespeare’s mind (and into mine as well). That is the ‘route’ through which it ‘influenced’ Shakespeare’s play. More generally, later cultural beings are the result of the intermixing of earlier cultural beings in the minds of authors.
Information in Cultural Evolution
I have two objections to standard memetic talk of memes as cultural information. One is simply that the concept is not very clear (see the addendum). The other is that it is used to paper over the very tricky and interesting question of how one mind influences another. “Oh, one mind just transfers information to the other mind.”
Not only is this a mistaken account of what physically happens during communication (which Michael Reddy critiqued with is account of the conduit metaphor) but it also glosses over the fact that communication is often imperfect. That very imperfection is one potential source of cultural variation. The mind that reads a signal, any signal, is not identical to the mind that sends it, and so it may misread the signal. Where the two minds are in face-to-face interaction it may be possible to negotiate a satisfactory understanding. Where negotiation is impossible, misunderstanding may be inevitable and hard to eradicate.
One case that I find particularly interesting is that of the musical interaction between European-Americans and African-Americans in 20th century musical styles. Instrumental styles pass from black music to white music more easily than do vocal styles, but even there we can see differences. The basic harmonic and melodic practices transfer easily enough, but the rhythmic nuances do not. The neuromuscular systems that reconstruct the music are different from those that produce it. Thus Pat Boone’s versions of Little Richard’s tunes are anemic in comparison to the originals. The “information” didn’t quite “transfer.”
Addendum: John Wilkins on Information
This is from John Wilkins’ entry, Replication and Reproduction, in the Stanford Encyclopedia of Philosophy:
The literature dealing with information is both extensive and factious. Several different formal analyses of information can be found and very little agreement about which analysis is best for which subjects. On one point these scholars tend to agree—cybernetic information and communication-theoretic information will not do for replication in biological contexts. The best bet is semantic information (Sterelny 2000a; Godfrey-Smith 2000; Sarkar 2000). The trouble is that no widely accepted version of semantic information exists. Winnie (2000) distinguishes between Classical and Algorithmic Information Theory and opts for a revised version of the Algorithmic Theory. But once again, the problem is that no such formal analysis currently exists. In the face of all this disagreement and unfinished business, biologists such as Maynard Smith (2000) maintain either that informal analyses of “information” are good enough or that some future formal version of information theory will justify the sorts of inferences that they make. The sense of “information” as used in the Central Dogma of molecular biology, which states that information cannot flow from protein to DNA, is more like a fit of template, or the primary structure of the protein sequence compared to the sequence of the DNA base pairs. Attempts have been made in what is now known as bioinformatics to use Classical Information Theory (Shannon's theory of communication) to extract functional and phylogenetic information (Gatlin 1972; Maclaurin 1998; Wallace and Wallace 1998; Brooks and Wiley 1988), but it appears to have been unsuccessful in the main. While the most likely conclusion is that no version of information theory as currently formulated can handle “information” as it functions in biology (see Griffiths 2001 for further discussion), attempts have been made to formulate just such a version (Sternberg 2008; Bergstrom and Rosvall 2011). However, this undercuts the motivation for appealing to information theory to elucidate genes in the first instance.
I think the idea that the notion of memes-as-information obscures anything is bogus. Memetic information transfer consists of copying with mutation and selection. The "mutation" and "selection" components contain the elements that you claim are obscured. Yet this classification scheme is simple, obvious - and it doesn't "obscure" anything.
ReplyDeleteFWIW, I think that Wilkins is mistaken about Shannon/Weaver information. IIRC, his main objection was that it wasn't clear what observer to use in biology. Is the observer the scientist? Or the unborn future recipient of the genetic sequence? Observer-dependency in information theory is an extremely well understood issue. In practice, observers tend to agree on issues such as whether a gene was mutated during transmission or whether two genes contain Shannon mutual information indicating probable shared ancestry. If skeptical critics claim that you can't use Shannon/Weaver information theory to perform repeatable science, you can always prove them wrong - by specifying a reference observer - complete with priors and an updating scheme.
Mutural knowledge is important, I say quite a bit about it in my open letter to Steven Pinker.
ReplyDeleteOn biological information, I've been reading this:
van Baalen M. 2013. Biological information: why we need a good measure and the challenges ahead. Interface Focus 3: 20130030.
Abstract: Evolution can be characterized as a process that shapes and maintains information across generations. It is also widely acknowledged that information may play a pivotal role in many other ecological processes. Most of the ecologically relevant information (and some important evolutionary information too) is of a very subjective and analogue kind: individuals use cues that may carry information useful only to them but not to others. This is a problem because most information theory has been developed for objective and discrete information. Can information theory be extended to this theory to incorporate multiple forms of information, each with its own (physical) carriers and dynamics? Here, I will not review all the possible roles that information can play, but rather what conditions an appropriate theory should satisfy. The most promising starting point is provided by entropy measures of conditional probabilities (using the so-called Kullback–Leibler divergence), allowing an assessment of how acquiring information can lead to an increase in fitness. It is irrelevant (to a certain extent) where the information comes from—genes, experience or culture—but it is important to realize that information is not merely subjective but its value should be evaluated in fitness terms, and it is here that evolutionary theory has an enormous potential. A number of important stumbling points remain, however; namely, the identification of whose fitness it concerns and what role the spatio-temporal dynamics plays (which is tightly linked to the nature of the physical carriers of the information and the processes that impact on it).
The first sentence reads: "That information is a key concept in evolution is obvious". As Etienne Danchin puts it: "Reproduction implies the transmission of information across generations to allow the reconstruction of new individuals at every generation. Concepts of information are thus central to biology and in particular to the study of evolution."
DeleteThe article suggests we need a new concept of information to deal with analog information. That's silly. It also claims that most information theory has been developed to deal with "objective" rather than "subjective" information. That's not really correct: standard Shannon/Weaver information theory has always been observer dependent. The observer is modeled in Shannon information theory as the "destination" - one of the basic components of a messaging system. Shannon information theory is absolutely consistent with the same message having different information content to different receivers. These seem like fairly serious flaws in the article.
The call for a measure of adaptive information is fairly widespread - but, personally, I fail to see how this requires a new measure of information. IMO, biology requires new measures of information about as much as it needs new measures of length and time.
Close, but no cigar.
DeleteI've been thinking about this and, sure, information. Why not? But at that level, what can you do with the idea? It's pretty much mom and apple pie. How can you operationalize the concept to solve real problems? That's what Shannon and Weaver did for a certain range of problems, a range of problems that turns out to be large and useful. But no one's been able to operationalize a version of information that allows us to study the meaning of langauge strings. While language doesn't cover all of culture it covers quite a bit, so, if you want an informatic account of culture, you're going to have to come up with an informatic account of language. Without that, claims about culture as information are mostly smoke and mirrors, hand-waving and tap dancing.
This passage in van Baalen's article struck home for me:
Presenting his views on Dawkin's [36] notion of genes as units of evolution, Williams [50] made the important point that we should separate the physical manifestation of genes from their information content. Evolution, Williams argued, takes place in the information domain, or the ‘codical domain’ as he called it: information gets transmitted and DNA molecules eventually perish. What I wish to argue here is that this insight not only applies to genes, but should also be extended so as to incorporate all of the evolutionarily relevant forms of information: genes but also epigenes, genes from symbionts, various forms of experience, culture and so forth. In this information-based view, individuals (units of adaptation) are merely bundles of information.
This does not mean that physical form becomes irrelevant. On the contrary, the physical aspects of an information carrier determine its dynamics, through its capacity for change, storage and transfer. Different sources and origins of information may have very different kinds of dynamics indeed: some of my genes contain very ancient information, whereas my brain contains extremely recent (and mostly ephemeral) information [6]. The physics of a given carrier may have an effect on interpretation of the information it contains.
To us, the physical support of a message contributes to its meaning because it helps us to interpret it. If we were to encounter a piece of text in an unknown script, we would tend to guess its message differently if the text were hewn in a stone monument than if it were merely scribbled on a piece of paper. […] Danchin [6] calls the physical manifestation of information its ‘avatar’, which is a generalization of the concept of phenotype [51].
You mistake my intransigence on the point. I long ago entered the world in which one talks about information as a general phenomenon that applies in a wide range of cases. I don't need to know that. That's mom and apple pie and the flag all wrapped up in a bundle.
I'm interested in the various physical embodiments of information and the mechanisms by which information is conserved as it "flows" from one physical embodiment to another. Dan Dennett, it seems to me, is still living in a world where information is a new idea, a wonderful new information. Dennett hasn't yet absorbed the information epiphany; it's not yet percolated down into his conceptual bedrock.
Information, wow! You mean it's the same whether it's in a brain, or ink splotches on paper, or electrons through a wire, or vibrations in air? That's powerful stuff. Information isn't physical. It's well, it's information!
But it is always embodied in some physical medium. It is an attribute of that medium as approximate roundness is an attribute of an apple, or even mass. Understanding those physical embodiments and how they interact, that's where the game is these days.