Tuesday, May 21, 2013

Roles in Cultural Selection: Replicators, Interactors, and Beneficiaries, or, Where’s the Memes?

Once again, cultural evolution, and the problem of memes: What are they? Where are they? What do they do? While the general case does interest me, culture is so various that it is impossible to think about it directly. One has to think about specific cases. As details are important, I want to choose a fairly specific case, that of jazz in mid-20th-Century America. I want you to imagine that you’re in a jazz club in, say, Philadelphia, in, say, mid-October of 1952. It’s 1:30 in the morning, and the tune is Charlie Parker’s “Dexterity.” The piano player counts it off–ah one, ah two, one two three four

But we’re getting ahead of ourselves. We need a little conceptual equipment before considering the example. It’s the conceptual equipment that’s in question. Make no mistake, the concept of memes is conceptual equipment, and it’s confused and confusing.

Roles in Cultural Selection

Genes and phenotypes play certain roles in a more or less standard account of biological evolution. The phenotype interacts with the environment, where it either succeeds or fails at reproduction, depending on the “fit” between its traits and that environment. Where the phenotype is successful at reproduction, it is the genes which are said to carry heredity from one generation to the next.

In one very widespread account genes are said to be replicators. That is to say, replication is the role they play in evolutionary change. Here’s what Peter Godfrey-Smith has to say about that (The Replicator in Retrospect, Biology and Philosophy 15 (2000): 403-423.):
In The Selfish Gene (1976), Richard Dawkins had argued that individual genes must be seen as the units of selection in evolutionary processes within sexual populations. This is primarily because the other possible candidates, notably whole organisms and groups, do not “replicate.” Organisms and groups are ephemeral, like clouds in the sky or dust storms in the desert. Only a replicator, which can figure in selective processes over many generations, can be a unit of selection.
At the same time Dawkins coined the term “meme” to name entities filling the replicator role in cultural evolution. Later on he used the term “vehicle” to designate the entity that interacts with the environment. In biological evolution it is phenotypes that are the vehicles. In cultural evolution, well, that’s a matter of some dispute. And that more general dispute–what are the roles in cultural evolution and what kinds of things occupy them?–is what interests me.

However, I don’t particularly like the term “vehicle.” As Godfrey-Smith has noted, following others, it is a gene-centric term, characterizing what entities do from the so-called “gene’s eye” perspective. I’d prefer a more neutral perspective and so will use a term coined by Richard Hull, “interactor.” Here are definitions as Godfrey-Smith gives them:
Replicator: an entity that passes on its structure largely intact in successive replications.
Interactor: an entity that interacts as a cohesive whole with its environment in such a way that this interaction causes replication to be differential.
We need one more role, that of beneficiary, as defined by Elisabeth Lloyd. “The beneficiary, for Lloyd, is the entity that ‘ultimately benefits’ from a process of evolution by selection” (Godfrey-Smith, see also Lloyd’s treatment of Units and Levels of Selection HERE). Godfrey-Smith goes on to suggest that “that most of the language of ... ‘ultimate benefit’ in this context is merely metaphorical.” That may be so, however, I find it useful, at least heuristically.

Consider for example gene-culture coevolution school of thinking, which offers a technically sophisticated treatment of cultural change. In that tradition it is biological organisms, mostly humans, but also chimpanzees, songbirds and some other animal species, that occupy the beneficiary role. But that is not the case in any version of memetics, where it is the memes that are the beneficiaries. In fact, part of the appeal of memetics has been that it offers a way of thinking about cultural practices, such as life-long celibacy, that are at odds with biological interests. While I’ve got problems with memetics, I am very much interested in accounts of cultural evolution it which it is the cultural entity that benefits from cultural evolution.

So, we’ve got three roles on the table: interactor, replicator, and beneficiary. Let’s return to some jazz club in Philadelphia on some night in 1952 and talk about that performance of “Dexterity.”

Late Night Dexterity

The environment in which any cultural practice thrives or dies is, of course, the social group. The group relevant to the imaginary jazz performance I invoked at the beginning is, first of all, the people present in the club to witness it, the audience and, of course the musicians themselves, not to mention the other people working at the club. The jazz audience is, of course, larger and more diffuse than the people in a given club on a given occasion. But we need not worry about the demographic details, not for the purposes of this example. All I want to do is to explicitly state that the evolutionary environment for music is some population of people.

And it is the performance that plays the interactor role, not the tune, in this case “Dexterity,” but the performance of the tune. It is the performance itself that the musicians and audience will find to be satisfactory or not. The tune is simply a source musical materials on which a performance can be based.

What, then, is the beneficiary of the performance? Well, one would think it is those musical materials in the tune, “Dexterity” in this case. That’s not all, but let’s start with that.

Of what does the tune “Dexterity” consist? The conventions of jazz have it that such tunes consist of a melody and a harmonic structure. A melody is a sequence of musical tones having specific pitches and durations. Melodies are concrete and, in principle, one can hum, whistle, or sing them. In practice, that might be difficult. “Dexterity” is one such difficult case as it is fast and complex, a characteristic of many bebop tunes—bebop, of course, is a particular jazz style and “Dexterity” is a tune in that style.

A harmonic structure is more abstract than a melody and can be realized equally well in many different ways, ways that will sound different in matters of detail. Instruments that can play only one note at a time, such as trumpet or saxophone, can play melodies that are consistent with a given harmonic structure but they have trouble conveying the structure directly. Multi-note instruments, such as piano or guitar, can convey harmonic structure more directly. Within the jazz world harmonic structures are generally notated as short strings of alphanumeric characters, each of which indicates a single chord: B7, Am, EMaj9, etc.

The harmonic structure of “Dexterity”¬–and this is why I chose it as an example–happens to derive from another well-known song, George Gershwin’s “I Got Rhythm.” There are so many songs that derive their harmonic structure from “I Got Rhythm”, especially in bebop, that “Rhythm Changes” has become a term of art within the jazz world. Obviously enough it designates the harmonic structure (chord changes) of “I Got Rhythm” considered as an autonomous musical entity (for a little history, see Cultural Evolution 4: Rhythm Changes 2).

So, a successful performance of “Dexterity” will benefit the specific melody of the tune, increasing that likelihood that audience members will want to hear it again and that the musicians will perform it again. It will also benefit the specific harmonic structure, which happens to derive from another tune, “I Got Rhythm”. The “Dexterity” melody is specific in a way that satisfies the definition of replicator, and I suppose that’s true of the harmonic structure–Rhythm Changes–as well. That’s how I treated it a couple of years ago, in Cultural Evolution 4: Rhythm Changes 1, where I talked of it as being a memetic entity. Still, it’s abstract nature continues to give me pause.

But there’s more to a performance than the materials provided by the melody and chord changes. I’m imagining that this specific performance is by a quintet consisting of trumpet, tenor sax, piano, bass, and drums¬¬–a standard line-up. In this performance the group plays the melody once at the beginning and once at the end. In between we have improvised solos. “Dexterity” provides the opening and closing melody and it provides the harmonic framework for all the improvisations. More materials are necessary.

The drummer needs to play appropriate patterns throughout. The same is true for the piano player and the bass player, who have to supply accompanying materials throughout the performance. Things are a bit different for the sax player and the trumpet player, who are responsible for playing the melody at the beginning and the end. When they solo, however, they’re on their own.

A good many of these bits and pieces–variously called riffs or licks–may properly be considered to be replicators. Some of them will be standard throughout the bebop community, if not jazz in general, and so are played by many musicians and on many different tunes. But some of them may be specific to these musicians, and even to this specific performance of “Dexterity.” Perhaps the piano player, for example, comes up with a new lick that she likes a lot and that the audience likes as well. So she uses that lick in subsequent performances, not only of “Dexterity”, but of other tunes. One of those performances gets recorded and other musicians here it and take up that lick. Within two or three years it’s spread throughout the bebop community (and 40 years later gets sampled by a hip hop artist). It’s become a meme.

It is unlikely, however, that we’ll be able to analyze the whole performance as but a complex collection of replicators (that is, memes). For one thing, there’s likely to be at least some specific phrases that aren’t derived from prior materials. For another thing, the way all these derived and novel elements fit together is important. A performance, the interactor, is not a collection of replicators and other stuff joined in random order. The order is important.

Thus I do not think we can reduce the interactor (the musical performance) to a collection of replicators and other stuff, any more than we can reduce a biological organism to a collection of genes. In biology there is a developmental process in which phenotypes emerge through a process in which genes interact with an environment. In music there is a performance process, if you will, that accomplishes an analogous task.

Not only do the musicians have to perform the music, but members of the audience must do so as well. The process of listening to music is not passive in the way that recording devices passively record sounds. Members of the audience take the sounds that they hear and construct connections between them. Bits a piece of this process may be explicitly conscious, such as the aha! when you notice that that sax player has just quoted the theme song from the Woody Woodpecker cartoons (which also is based on Rhythm Changes), but most of it is unconscious. It just happens.

Regardless of one’s level of performance skills, one has to learn to hear music. The audience for our imaginary performance is likely to include some people with sophisticated performance skills, people quite capable of performing “Dexterity.” But most probably have few performance skills; they may sing in the shower or in church but otherwise they don’t perform any music. Still, they had to learn how to hear jazz.

Some who is not particularly knowledgeable abou bebop might well take great pleasure in a good performance of “Dexterity” even if they don’t quite know what’s going on. They might not know, for example that the harmonic structure is that of “I Got Rhythm.” And they might not know that that structure is 32 bars long and divided into four sections of eight bars each. But there’s something going on that they like, to they applaud loudly and seek out other performances, by the same musicians, of the same tune, and in the same idiom.

Memes: Internal or External?

Where are these replicators, these memes, to use Dawkins’s term? In a standard view within memetics (e.g. Daniel Dennett’s view) the memes are patterns in people’s brains. But that isn’t the view I took in the above discussion. The melody for “Dexterity” is a concrete physical entity out there in the physical world where, not only can it be heard by people, but it can be picked up by recording equipment. The same is true of all those licks and riffs and even of the rather more abstract harmonic structure (which I’ve argued in some detail).

If these things didn’t exist in the external world as physical objects or properties of physical objects, they would be of no use to musicians. In order to perform together musicians need to coordinate their actions, and do so in a very exacting way, one whose temporal characteristics must be measured in milliseconds. The only means they have of doing this is to listen to the sound. If the memes cannot be identified with properties of the sound stream they cannot play a role in coordinating the musician’s interaction, nor can they be conveyed to an audience.

The memes are those properties of the sound stream through which the musicians couple their actions into a single coordinated activity. The coupling extends to the audience and you can see and hear in the way they tap their feet, gasp a particularly audacious lick, stop chattering at the performance builds, and so forth.

That is, musical memes perform a coupling function during performance and it is these coupling functions that must be learned from one person to another if the individual memes are to earn a long-term place in the musical repertoire.

I’m not denying that, when a musician learns the melody of “Dexterity” that something happens in the musician’s brain. But it’s not at all obvious to me that we accomplish anything useful by saying that that something has been replicated from the brain of another musician or musicians. And the same is true in the case of audience members. In order to appreciate the performance they must already know the performance conventions to some degree or another.

I see nothing to be gained by saying musical replication is a matter of transferring replicators between brains. Very obviously there IS replication of sounds. Without that there is nothing. It is the sounds that are the replicators, not the neural patterns in brains.

What then, is the biological analog of whatever it is that’s taking place in human brains during musical performances? Ontogenetic development. In the case of single-celled organisms that’s a relatively simple process of cell division, but it’s not a null process. Not only must the genetic material be replicated, but cell structures and organs must be created. In the case of multi-celled organisms the developmental process can be quite complex.

The same is true in music. Using the melody of “Twinkle, Twinkle, Little Star” as the basis for a performance can be a relatively simple and straightforward process. But a skilled improviser could create a very sophisticated piece of music on that material. Wolfgang Amadeus Mozart was such an improviser, though he worked in a different idiom. We don’t really know whether or not he gave improvised performances of that tune, but the fact that, he composed a sophisticated set of variations on is suggests that he probably did.

That, of course, raises the question of more or less richly annotated compositions, such as those in Western classical music. But I’ve done enough for one blog post. We can consider that question some other time.

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Addendum: When looking for memes in cultural evolution one can proceed under one of two assumptions: 1) Memes are a new kind of entity not yet identified in the human sciences. 2) Memes are entities that are already known but that have not heretofore been assigned to that role in the process of cultural evolution. I have taken the second position.

Addendum 2 (10 July 2013): In the above I've assigned the musical performance to the interactor role. But what do I mean by the performance? The complex sonic object that can, for example, be recorded? Or do I mean the (collective) neural event supported by that complex sonic object? The latter is what I had in mind in Chapter 8 of Beethoven's Anvil where I asserted that "the phenotypic role in music's evolution is played by performance-level attractors" (p. 192). Though a bit difficult to grasp, that's what I mean; it's the performance-level attractor that plays the interactor role.

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