evolution – Replicated Typo

Divergence and Reticulation in Cultural Evolution

That’s the title of my latest working paper. You can download it here: https://www.academia.edu/41095277/Divergence_and_Reticulation_in_Cultural_Evolution_Some_draft_text_for_an_article_in_progress.

And you can participate in a discussion of it here: https://www.academia.edu/s/9b97738023.

Abstract, Contents, and introductory material below.

* * * * *

Abstract: In a recent review of articles in computational criticism Franco Moretti and Oleg Sobchuk bring up the issue of tree-like (dendriform) vs. reticular phylogenies in biology and pose the question for the form taken by the evolution of cultural objects: How is cultural information transmitted, vertically (leading to trees) or horizontally (yielding webs)? Dendriform phylogenies are particularly interesting because one can infer the phylogenetic history of an ensemble of species by examining the current state. The horizontal transmission of information in webs obscures any historical signal. I examine a few cultural examples in some detail, including jazz styles and natural language, and then take up the 3300 node graph Matthew Jockers (Macroanalysis 2013) used to depict similarity relationships between 3300 19th century Anglophone novels. The graph depicts a web-like mesh of texts but, uncharacteristically of such patterns, also exhibits a strong historical signal. (Just how that is possible is the subject of another draft.)

Contents
What’s Up? 1
The need for theory: Cultural evolution 2
Trees, Nets, and Inheritance in Biology 4
Divergence and reticulation in culture 7
Jockers’ Graph, a reticulate network 18 Appendix: A quick guide to cultural evolution 22

What’s Up?
In the past year we have had two reviews of recent work in computational criticism:

Nan Z. Da, The Computational Case against Computational Literary Studies, Critical Inquiry 45, Spring 2019, 601-639.
Franco Moretti and Oleg Sobchuk, Hidden in Plain Sight: Data Visualization in the Humanities, New Left Review 118, July August 2019, 86-119.

Though both are critical of that work, they are quite different in tone and intent. Da is broadly dismissive and sees little value in it. Moretti and Sobchuk see considerable value in the work, but are disappointed that it is largely empirical in character, failing to articulate a theoretical superstructure that deepens our understanding of literary history.

I’ve been working on a critique of those papers which seems to have expanded into a primer on thinking about literary culture as an evolutionary phenomenon. I’m currently imaging that the final article will have five parts:

Genealogy in literary history
Unidirectional trends in cultural evolution
Jockers’ Graph: Direction in the 19th century Anglophone novel
Expressive culture as a force in history
A quick guide to cultural evolution for humanists

I have already posted draft material for the second part of the article, which centers on a graph from Matthew Jockers’ Macroanalysis (2013) [1].

That graph was my central concern from the beginning. It is the most interesting conceptual object I’ve seen in computational criticism, but it is easily misunderestimated and glossed over – as far as I know Da’s understandable but unfortunate dismissal is the only treatment of it in the referred literature. The problem, it seems to me, is that a proper appreciation of it requires a conceptual framework that doesn’t exist in the literature. My objective, then, is to begin assembling such a framework.

Moretti and Sobchuk didn’t mention it at all as their review was confined to journal articles. But it merits consideration in a framework that did establish in their review, if only barely. The invoke a distinction from evolutionary biology, that between tree-like (dendriform) phylogenies and free-form or web-like phylogenies, and suggest that it is important for understanding the relationship between literary for and history (pp. 108 ff.). Jockers graph is web-like network of texts but it exhibits an important feature of dendriform phylogenies, it displays a strong temporal signal. Thus a discussion of issues raised by Moretti and Sobchuk is a good way to begin constructing the missing conceptual framework.

This document consists of draft material for the discussion, the first part of the planned article, and the fifth part. The fifth part, the appendix is straight forward, and I have included it the end of this document. Once I have discussed the issue of dendriform vs. web-like relationships I introduce Jockers’s graph.

In the second part of the article, unidirectional trends in cultural evolution, I plan to say a few words about time and directionality. I will then take up a number of the examples Moretti and Sobchuk review in their article. While they don’t frame them as evidence for unidirectional trends, that is what they are. From my point of view that’s the most interesting and important aspect of their review, they gather those articles into one place. I will be placing those articles in the context of other work showing unidirectional trends.

I don’t yet know whether I’ll post draft materials on the second and fourth sections before drafting the whole article.

The need for theory: Cultural evolution

Now let us turn to Moretti and Sobchuk. Here is their penultimate paragraph (112-113):

Tree-like, linear, reticulate . . . why should we even care about the shape of cultural history? We should, because that shape is implicitly a hypothesis about the forces that operate within history; the tentative, intuitive beginning of a theoretical framework. ‘Theories are, even more than laboratory instruments, the essential tools of the scientist’s trade’, wrote Thomas Kuhn over a half century ago; too bad we didn’t heed his advice. Although the crass anti-intellectualism of Wired—‘correlation is enough’, ‘the scientific method is obsolete’—has fortunately remained an exception, what seems to have happened is that, as the amount of quantitative evidence at our disposal was increasing, our attempts at in-depth explanations were losing their strength. Disclaimers, postponements, ad hoc reactions, false modesty, leaving inferences ‘for another day’ . . . such have been, far too often, our inconclusive conclusions.

Ah, “the forces that operate within history”, that’s what we’re after, no? And we’re not going to get there without theory, yes?

I believe that that theory will be about culture as an evolutionary phenomenon. It is clear that both Moretti and Sobchuk believe that as well, but they do not introduce or frame their essay that way. They introduce it as a methodological inquiry into the use of visualization. It is only as the essay unfolds that evolution emerges as an ideational engine parallel to if not quite driving their interest in visualization.

Accordingly it is necessary to make some preliminary remarks about cultural evolution. Work in cultural evolution has blossomed in the last quarter century but:

While humanities and social science scholars are interested in complex phenomena—often involving the interaction between behaviour rich in semantic information, networks of social interactions, material artefacts and persisting institutions—many prominent cultural evolutionary models focus on the evolution of a few select cultural traits, or traits that vary along a single dimension […]. Moreover, when such models do build in more traits, these typically are taken to evolve independently of one another […]. Within cultural evolutionary theory, this strategy holds that the dynamics and structure of cultural evolutionary phenomena can be extrapolated from models that represent a small number of cultural traits interacting in independent (or non-epistatic) processes. This kind of strategy licences the modelling of simple trait systems, either with an eye to describing the kinematics of those simple systems, or to illuminate the evolution and operation of mechanisms underpinning their transmission […]. [2]

Hence, if students of literature want to think about culture as a phenomenon of evolutionary processes, we will not find suitable models and methods in existing work on cultural evolution. Though we certainly need to be aware of and conversant with that work, we are going to have to construct models and methods suitable to our material. That is the primary objective of this essay. To that end, then, I will be introducing a several of examples of work on cultural evolution in other domains.

Biologists, of course, has been developing evolutionary theory over the last half century. While they agree on basic issues, many details are still under contention. When we, then, as students of literary culture set out to adapt evolutionary theory to the analysis of literary phenomena, just what do we take from biological thinking and how do we do it? Various approaches exist in the general cultural literature, but this is hardly the place to sort through them – though I have prepared a brief appendix with pointers into those discussions. What Moretti and Sobchuk seem to have taken over is the distinction between tree-like lineages and more chaotic, network-like lineages. So that’s where I will start.

Where I am going, though, is toward an argument which says that that distinction is a reflection of the mechanisms that underlie the evolutionary process and it is to those mechanisms that we must look in adapting evolutionary theory to the study of human culture. Cultural evolution unfolds though collectivities of human minds, and they give cultural evolution a different texture, if you will, and different large scale patterns.

References

[1] On the direction of literary history: How should we interpret that 3300 node graph in Macroanalysis, Version 2, https://www.academia.edu/40550795/On_the_direction_of_literary_history_How_should_we_interpret_that_3300_node_graph_in_Macroanalysis_Version_2.

[2] Buskell, A., Enquist, M. & Jansson, F. A systems approach to cultural evolution. Palgrave Commun 5, 131 (2019) pp. 4-5, doi:10.1057/s41599-019-0343-5 https://rdcu.be/bVNtP.

Berwick, Friederici, Chomsky, Bolhuis (2013): Evolution, brain, and the nature of language

UPDATE: This paper is now a Trends in Cognitive Sciences Free Featured Article and is available for free here

Noam Chomsky, who infamously stated that the field of language evolution research is “a burgeoning literature, most of which in my view is total nonsense” (see, e.g. here), has a new paper on the topic in press (together with linguist Robert Berwick and neuroscientists Angela Friederici and Johan Bolhuis) called Evolution, brain, and the nature of language (here, unfortunately it’s behind a paywall).

Here’s the abstract:

Language serves as a cornerstone for human cognition, yet much about its evolution remains puzzling. Recent research on this question parallels Darwin’s attempt to explain both the unity of all species and their diversity. What has emerged from this research is that the unified nature of human language arises from a shared, species-specific computational ability. This ability has identifiable correlates in the brain and has remained fixed since the origin of language approximately 100 thousand years ago. Although songbirds share with humans a vocal imitation learning ability, with a similar underlying neural organization, language is uniquely human.

Also interesting is their figure on the Desing of the language system:

“The basic design of language. There are three components: syntactic rules and representations, which, together with lexical items, constitute the basis of the language system, and two interfaces through which mental expressions are connected to the external world (external sensory-motor interface) and to the internal mental world (internal conceptual-intentional interface).”

This still looks very much like the model advocated in for example, the influential and controversial Hauser/Chomsky/Fitch 2002 Science paper (see e.g. here) and from a brief look through the review. The paper also reiterates the view that language is primary an instrument aiding internal thought, and its use for communication is a later by-product (a view that has been thouroughly criticized, by for example Steven Pinker and Ray Jackendoff, e.g. here):

“communication, an element of externalization, is an ancillary aspect of language, not its key function, as maintained by what is perhaps a majority of scholars (cf. [Jim Hurford, Michael Tomasello], among many others). Rather, language serves primarily as an internal ‘instrument of thought’”

Babies know who’s boss, whose boss, and who knows what else.

A forthcoming paper (grateful nod to ICCI) in PNAS from Olivier Mascaro and Gergely Csibra presents a series of experiments investigating the representation of social dominance relations in human infants, and it’s excellent news: we’re special.

Social dominance can be inferred in a couple of ways. Causal cues such as age, physical aggression and size can tell us about the dominance status of an individual quite intuitively, so we can make a sensible decision about whether or not we get into a scrap with them. Another way we can establish this is to look for direct realisations of dominance, such as who gets the banana if two hungry chimps both want it; chances are, little Pan Pipsqueak isn’t going to get a look in. In order to be useful, we also have to use this information to expect certain things from the individuals around us, so those representations have some property of stability across time that allows us to have those expectations. The question being explored in this paper is whether the representations we have are about the relationship between the two agents who want the banana, or the individual properties each of them has.

In a series of experiments using preferential looking time as a dependent measure, human infants (9 and 12 month olds) were exposed to videos of geometric figures exhibiting similar goal-directed behaviour. Then they would watch, say, a dominant triangle picking up the last figurative banana when the nondominant pentagon also wanted it. For expository purposes and posterity’s sake, I have constructed an artist’s impression of a dominant triangle and a subordinate pentagon in MSPaint (below, right):

Subordinate_Pentagon — A dominant triangle and subordinate pentagon (artist’s impression).

I’m not just showing off my extraordinary artistic talent here; the good thing about these agents is that there are none of the cues like size or aggression that can give rise to the assignment of individual dominance properties. The task also doesn’t indicate anything similar; it’s just about who gets the desired object when there’s only one left. In other words, the goal-directed actions of two agents are in opposition. After seeing a triangle beat a pentagon to an object of ‘banana’ status, 12 month olds looked for longer when they were then presented with an incongruent trial where the pentagon gained over the triangle. 9 month olds (understandably?) couldn’t care less. So, on the basis of this social interaction alone, the 12 month olds were able to notice when something unexpected happened.

To rule out the possibility that this was just the result of some simple heuristic such as “when triangle and pentagon are present, triangle gets the object” and make sure the infants really were assigning some dominance, another experiment (with 12 and 15 month olds) showed the same test video of the two agents collecting little objects. This time, however, the preceding video was of the triangle dominating a little walled-in space that the pentagon also wanted to inhabit. The 12 month olds had no idea what was up, but the 15 month olds generalised from the first “get out of my room” interaction to the “I get the last banana” interaction. So, 15 month olds can extract, just from watching a social interaction, the dominance status of agents and can generalise that information to novel situations. So if a 15 month old watches you lose your favourite seat in front of the TV, they’ll also expect you to miss out on the last slice of pizza, because you’re a loser.

What we still don’t know is whether they think your belly is inherently yellow, or if you’re just a pushover when interacting with a particular person. Is it the relationship between the triangle and pentagon that the babies are tracking, or do they just give each agent some sort of dominance score? This was addressed in experiment 4, where infants were presented with two interactions: one between A and B, where A wins, and then another between B and C, where B wins. If the babies are assigning an individual value to each agent, they should have some sort of linear, transitive representation of dominance like A > B > C. If they’re then presented with a novel interaction between A and C, they would have the expectation that A will beat C. So if they stare in surprise at a trial where C wins, we know it’s violated that kind of expectation, and that they’re representing this stuff linearly – I.E. each agent has a dominance value. In contrast, if the infant is tracking the relations between agents, they can’t really have an expectation of what will happen when A and C both want a banana, because they’ve never seen C before. The results find that the infants look preferentially when they get an incongruent trial using agent pairs they have seen before – as we’d expect from the previous experiment. When they’re presented with a new “I get the last banana” interaction between A and C, however, there’s nothing startling about it when C wins – which means their expectations are not based on something like A > B > C.

The only tiny little harrumph I have about this result is that all it does is falsify the linear representation account. Though I think their account is absolutely right, it’d be nice to see something more predictive come out of the relation-representation hypothesis that is a little more falsifiable. But this result is pretty huge, and stands in contrast with what we know about social cognition in other animals like baboons (Cheney et al, 1995; Bergman et al, 2003), lemurs (Maclean et al., 2008) and even pigeons (Lazareva & Wasserman, 2012), who seem to employ this sort of hierarchical, transitive inference when presented with novel interactions. It may also muddy the waters a little when we want to make the appealing claim that, since language surely emerged in order to enable communication as we navigated a social environment, hierarchical social cognition gives rise to the processing of languagey things like hierarchical syntax or our semantic representation (Hamilton, 2005), which can be characterised as hierarchical (e.g. hyperonym > hyponym). If we consider the nature of the human social environment, though, it should seem more intuitive that something more reliable than simple transitive inference is necessary in order to successfully navigate through our interactions. Due to our prolific production of (and reliance on) culture, humans have a much more diverse range of social currencies, which correspond to values for things like money, intelligence, blackmail information, who your friends are, ad infinitum. That means it’s pretty reasonable that our social cognition needs new strategies in order to get by; we have a little more to consider than just who’s big and angry enough to get all the bananas.

References

Bergman, T., Beehner, J., Cheney, D. & Seyfarth, R. (2003) “Hierarchical Classification by Rank and Kinship in Baboons” Science 14(302), 1234-1236.

Cheney, D., Seyfarth, R. & Silk, J. (1995) “The response of female baboons (Papio cynocephalus ursinus) to anomalous social interactions: evidence for causal reasoning?” Journal of Comparative Psychology 109(2), 134-141.

Hamilton, D.L. (2005) Social Cognition: Key Readings (p. 104) Psychology Press

Lazareva, O. & Wasserman, E. (2012) “Transitive inference in pigeons: measuring the associative values of stimulus B and D” Behavioural Process 89(3), 244-255.

Maclean, E., Merritt, D. & Brannon, E.M. (2008) “Social complexity predicts transitive reasoning in prosimian primates” Animal Behaviour 76(2), 479-486.

Mascaro, O. & Csibra, G. (forthcoming) “Representation of stable dominance relations by human infants” Proceedings of the National Academy of Sciences

Language Evolution and Levels of Explanation

A somewhat contentious debate among the behavioural sciences is currently underway concerning Mayr’s division of causal explanations in evolutionary theory. Here I’m going to give you a brief rundown of two papers in particular, before I chip in my two-cents about how other insights from the theoretical literature can inform this debate. It seems the discussion is just getting started with respect to cultural evolution, so it’d be interesting to hear other peoples’ comments from either camp.

Over the years, evolutionary theorists have tried to make logical divisions between the kinds of things we can ask about, with a view to making it clear what exactly scientific studies can tell us. A dominant paradigm dividing two levels of causation for biological features we see in the world is Mayr’s distinction between ultimate and proximate causes. Ultimate causation explains the proliferation of a trait in a population in terms of the evolutionary forces acting on that trait. For example, peahens that prefer peacocks with larger tails (an honest signal of fitness following the handicap principle) will have stronger or more successful offspring, and so this preference proliferates along with larger peacock tails. Proximate causation uses immediate physiological and environmental factors to explain a particular peahen’s penchant for a large-tailed peacock in a mate choice trial, where the signal of the peacock’s large tail elevates the hormone levels in the peahen and copulatory behaviour ensues. Although the behaviour in both of these examples is the same, the levels of explanation are based on different sets of factors.

In Perspectives on Psychological Science last year, a paper by Scott-Phillips, Dickins and West voiced some concerns about these two levels of causation being conflated in the behavioural sciences. In particular, they addressed instances where proximate explanations of traits are being framed as ultimate ones. The paper points specifically to studies of the evolution of cooperation, transmitted culture and epigenetics to illustrate this. Regarding the evolution of cooperation, they point to an instance where ‘strong reciprocity’ (an individual’s propensity to reward cooperative norms and sanction violation of these norms) is purported to be an ultimate explanation of why humans cooperate, rather than a proximate mechanism that enables such cooperation.

Table of proximate and ultimate explanations. For the topic of 'linguistic structure', cultural transmission is listed as a proximate explanation, and the adaptive benefit of cooperative activity through communication is given as an ultimate explanation., — Table 1 from Scott-Phillips et al. (2011), highlight added.

Among the examples was the feature of linguistic structure (see table 1 from paper above), where several studies pointed to the cultural transmission process as an ultimate explanation of linguistic structure. They suggest that cultural transmission constitutes a proximate process, because it gives the means by which linguistic structure is expressed – and this is how cultural transmission contributes to what the linguistic structure looks like. One analogy might be that the vibrating of my particular vocal cords is a proximate mechanism giving rise, in part, to how my voice sounds, rather than an ultimate explanation of why I vocalise. Since an ultimate account must suggest how a trait contributes to inclusive fitness in order to explain its prevalence in humans, they uncontroversially venture that the ultimate rationale for the ubiquity of linguistic structure is that it greater enables communication (and therefore increases inclusive fitness by enabling cooperative activity).

An opposing view was later published in Science by Laland, Sterelny, Odling-Smee et al., who suggest that the use of Mayr’s division of ultimate and proximate causation is not helpful to all evolutionary investigations, and even hampers progress. The grounds for rejecting Mayr’s paradigm seem to lie largely in what Laland et al. term “reciprocal causation”. That is, that “proximate mechanisms both shape and respond to selection, allowing developmental processes to feature in proximate and ultimate explanations”. After aligning proximate explanations with ontogeny and ultimate explanations with phylogeny, they suggest that what we may have called ultimate and proximate features are no longer sharply delineated, and that these reciprocal processes mean that the source of selection sometimes cannot be separated. They present an idea from the field of evolutionary-developmental biology that, if a developmental process makes some variant of a trait more likely to arise than others, then this proximate mechanism helps to construct an “evolutionary pathway”.

Flow charts presenting alternative processes for Biological evolution, Cultural evolution and Gene-culture coevolution — Figure 2 from Laland et al. (2011)

The paper also highlights developmental plasticity, and gene-environment interaction more broadly (see fig. 2 from paper, above), as a process where reciprocal causation offers an evolutionary explanation conceptually comparable to ultimate causation. Talking specifically on the topic of linguistic structure, they present the debate about whether specific design features of language are attributable to biological or cultural evolution. The paper points out that cultural evolution determines features of linguistic structure – for example, word order – and that the existing word order determines that of future speakers. Indeed, at the Edinburgh LEC we know that transmission by iterated inductive inference under general conditions can explain particular structures in languages. That cultural evolution determines the variation between languages, Laland et al. say, provides evidence that it is an evolutionary force comparable to natural selection (and, therefore, ultimate explanation).

What follows is a collection of my thoughts on the matter, which are (spoiler alert) largely in support of the Scott-Phillips et al. paper. I hope others more experienced in cultural evolution studies than I will contribute their perspective.

It seems to me that there are a few assumptions made in the Laland et al. paper that are not quite in line with how Mayr himself understood the paradigm. Perhaps much can be learned from this debate’s previous incarnation, when Richard C. Francis made similar arguments against the ultimate/proximate distinction in 1990. In his critique, he equated ultimate causation with phylogeny and proximate causation with ontogeny – an approach that was rebuked by Mayr in 1993, who made the point that “all physiological activities are proximately caused, but is a reflex an ontogenetic phenomenon?”. Mayr’s response is actually rather unhelpful in addressing the arguments fully, and this statement is particularly dense. But what he is getting at here is the idea that interaction with the environment that gives rise to adaptive behaviours (such as recoiling instantly from a hot stove) is itself subject to selection, and thus constitutes a proximate explanation of causation. Relatedly, he points out that most components of the phenotype are indeed the result of genetic contribution and interaction with the environment, which has been successfully explored in biology within the traditional theoretical paradigm.

A perhaps more nuanced account of how we can divide the possible explanations of biological phenomena is offered by Tinbergen in his “four questions”, where ultimate explanations are further subdivided into Function (concerning the adaptive solution to a survival problem favoured by natural selection) and Phylogeny, which is a historical account of when the trait arose in the species, and importantly includes processes other than natural selection that give rise to variation – such as mutation, drift and the constraints imposed by pre-existing traits (see blind spot example below). Proximate explanations are further split into Mechanism (immediate physiological/environmental factors causal in how the trait operates in the individual) and Ontogeny (the way in which this trait develops over the lifetime of the individual). As a simple example, here is the paradigm applied to a trait like mammalian vision that I lifted from Wikipedia:
Ultimate
Function: To find food and avoid danger.
Phylogeny: The vertebrate eye initially developed with a blind spot, but the lack of adaptive intermediate forms prevented the loss of the blind spot.
Proximate
Causation: The lens of the eye focuses light on the retina
Ontogeny: Neurons need the stimulation of light to wire the eye to the brain within a critical period (as those awful studies of blindfolded kittens illustrated).
A schematic below, adapted from Tinbergen (1963) shows how these levels of causation may interact with one another, which appears to communicate something roughly comparable to the importance Laland et al. place on “reciprocal causation” in the formation of adaptive variants:

Flow chart showing the interaction of functional, phylogenetic, mechanistic and ontogenetic explanations — Adapted from Tinbergen (1963); Causal Relationships

Applied to the debate outlined above, it would seem that there is no apparent reason that a process of gene-environment interaction – including the cultural environment – can’t itself be subject to selection, or that developmental plasticity itself is not an adaptation in need of an ultimate explanation. It has long been the case that behaviour is no longer understood as either “nature” or “nurture”, but gene-environment interaction, with varying levels of heredity. The “reciprocal causation” suggested in Laland et al.’s paper, is (as they point out) very common in nature; feedback loops are uncontroversial proximate processes in biology. That a proximate process may give rise to a dominant variant of a trait in a population does not explain why it is adaptive, and this points to another problem with the proposing the abandonment of Mayr’s paradigm: a logical division of levels of explanation doesn’t seem to be the sort of thing that can be rendered outdated by empirical evidence. Indeed, claims about the particulars of traits and processes (and languages) themselves are a matter for empirical data – but the theoretical issue about the level of explanation that data is useful for does not itself seem to be subject to empirical findings.

The finding that a proximate process such as cultural transmission gives rise to a trait that is prolific in a population is itself exciting and surprising, and even shows us that the pressure for making language easier to learn gives us adaptive languages to learn; however, it could be argued that it is this process that is adaptive, and that the reason why humans so heavily rely on this process is an ultimate explanation.

One way of resolving these two perspectives may be to place cultural processes that give rise to variation at the level of what Tinbergen labels Phylogenetic (one subset of ultimate) explanation, as it concerns processes which produce some heightened frequency of traits over a language’s history. An explanation at the level of Phylogeny still must make recourse to natural selection at some point, since variants that result from mutation or drift are retained because of their adaptive value (or an adaptive trade-off). This approach may be a problem for the current understanding, which holds that the features resulting from cultural processes are themselves adaptive and therefore comparable to what Tinbergen labels Function.

The problem with this is that calling particular structures of language ‘adaptive’ obscures what it is about Language that is actually being selected for. To flesh out what I mean, I think it’s useful to consult Millikan’s (1993) distinction between Direct Proper Function and Derived Proper Function (… bear with me, it’ll be worth it, honest). The Direct Proper Function of a given trait T can be thought of as a “reproduction” of an item that has performed the exact same adaptive function F, and T exists because of these historical performances of F. Sperber and Origgi (2000) use the illustrative example of the heart, where the human heart has a bunch of properties (it pumps blood, makes a thumping noise, etc), but only its ability to pump blood is its Direct Proper Function. This is because even a heart that doesn’t work right or makes irregular thumping noises or whatever, still has the ability to pump blood. Hearts that pump blood have been “reproduced through organisms that, thanks in part to their owning a heart pumping blood, have had descendents similarly endowed with blood-pumping hearts”.

The Derived Proper Function, however, refers to a trait T that is the result of some device that, in some environment, has a Proper Function F. In that given environment, F is usually achieved by the production of something like T. If I unpack this idea and apply it to language, we can understand it as the acquisiton and production of a device that, in this environment, leads to, say, a particular SVO language, T. The Proper Function of adaptive communication is performed by T in this case, but could also be performed by any number of SOV, VSO, etc Ts in other cases. In other words, the Proper Function of this language is not the word order itself, but communication. The word order is the realisation of this device that is reproduced because of the performance of T in a particular environment, but does not necessarily lead to T in the next incarnation of that device (i.e. My child, if born and raised in Japan, will speak Japanese). We see, then, that a proximate process resulting in what a particular language spoken by a given population looks like does not necessarily speak to the evolutionary function. In other words, it is the device that allows the performance of Language that is adaptive, not the individual language itself.

One question being asked in the study of cultural transmission is why a particular language looks like it does, while we also know that there are 6000 different versions that perform the same (ultimate) function. I would even argue that asking how proximate processes shape languages is actually the most exciting and interesting avenue of inquiry precisely because it’s so blindingly obvious what the adaptive function of language is. But perhaps the value in this endeavour is somewhat neglected, in part, because of the same impression that Francis (1990) had: “the attitude, implicit in the term ultimate cause, [is] that these functional analyses are somehow superordinate to those involving proximate causes” which would be a shame. It seems to me that the coarse grain of ultimate vs proximate perhaps doesn’t do enough to help complex proximate study to position itself in the wider theoretical framework, and the best way to proceed from this might be to couch explanation in terms of Function, Phylogeny, Ontogeny and Mechanism. I think more fine-grained terminology grants us more explanatory power, in this case.

A final question in this debate that came up too many times during discussions with the LEC is: what does keeping the traditional paradigm “buy us”? Well, the first answer to this is consilience with one of the most successful and robust theories in science. The same sentiment has been communicated by Pinker and Bloom (1990), who said: “If current theory of language is truly incompatible with the neo-Darwinian theory of evolution, one could hardly blame someone for concluding that it is not the theory of evolution that must be questioned, but the theory of language”. Part of the reason this debate may have arisen is that studies of cultural evolution have used evolutionary theory as an incredibly fruitful way of analysing cultural processes, but additional acknowledgement about how cultural adaptation is different to biological adaptation may be necessary. This difference is an aspect of Laland’s paper (shown in Fig 2) that I think is important, as it’s part of the reason that more nuanced frameworks for cultural evolution are now needed. Without this widespread acknowledgement, cultural evolution may be considered an extension of biological evolutionary theory instead of a successfully applied metaphor. It seems to me that the side of this debate one falls on is well predicted by whether one subscribes to the former interpretation of cultural evolution or the latter.

Knowing which level of explanation current work pertains to is a valuable part of evolutionary exploration, and abandoning this in favour of an approach where proximate processes are explanatory ends to themselves may mean the exploration of Function and Phylogeny may suffer. That said, it is telling, I think, that even in seeking to abandon the proximate/ultimate distinction, we must still exploit this existing terminology in order to explain such a position. That natural selection has explained countless adaptations in all living things is certainly not trivial, and to reject the theory giving rise to ultimate explanations as they’re currently defined is to reject this fundamental aspect of evolutionary theory. The big problem seems to be that we’re coming to understand proximate processes as so elaborate and complex, that a more nuanced framework is needed to deal with the dynamics of those processes. I reckon, however, that such a framework can be developed within the traditional paradigms of evolutionary theory.

References

Francis, R.C. (1990) – “Causes, Proximate and Ultimate” Biology and Philosophy 5(4) 401-415.

Laland, K., Sterelny, K., Odling-Smee, J., Hoppitt, W. & Uller, T. (2011) – “Cause and Effect in Biology Revisited: Is Mayr’s Proximate-Ultimate Distinction Still Useful?” Science 334, 1512-1516.

Mayr, E. (1993) – “Proximate and Ultimate Causations” Biology and Philosophy 8: 93-94.

Millikan, R. (1993) – White Queen Psychology and Other Essays for Alice, Cambridge, Mass: MIT Press.

Pinker, S. & Bloom, P. (1990) – “Natural language and natural selection” Behaviour and Brain Sciences 13, 707-784.

Scott-Phillips, T. Dickins, T. & West, S. (2011) – “Evolutionary Theory and the Ultimate-Proximate Distinction in the Human Behavioural Sciences” Perspectives on Psychological Science 6(1): 38-47.

Sperber, D. & Origgi, G. (2000) – “Evolution, communication and the proper function of language” In P. Carruthers and A. Chamberlain (Eds.) Evolution and the Human Mind: Language, Modularity and Social Cognition (pp.140-169) Cambridge: Cambridge University Press.

Tinbergen, N. (1963) “On Aims and Methods in Ethology,” Zeitschrift für Tierpsychologie, 20: 410–433.

In Search of the Wild Replicator

The key to the treasure is the treasure.
– John Barth

In view of Sean’s post about Andrew Smith’s take on linguistic replicators I’ve decided to repost this rather longish note from New Savanna. I’d orignally posted it in the Summer of 2010 as part of a run-up to a post on cultural evolution for the National Humanities Center (USA); I’ve collected those notes into a downloadable PDF. Among other things the notes deal with William Croft’s notions (at least as they existed in 2000) and suggests that we’ll find language replicators on the emic side of the emic/etic distinction.

I’ve also appended some remarks I made to John Lawler in the subsequent discussion at New Savanna.

* * * * *There’s been a fair amount of work done on language from an evolutionary point of view, which is not surprising, as historical linguistics has well-developed treatments of language lineages and taxonomy, the “stuff” of large-scale evolutionary investigation. While this work is directly relevant to a consideration of cultural evolution, however, I will not be reviewing or discussing it. For it doesn’t deal with the theoretical issues that most concern me in these posts, namely, a conceptualization of the genetic and phenotypic entities of culture. This literature is empirically oriented in a way that doesn’t depend on such matters.

The Arbitrariness of the Sign

In particular, I want to deal with the arbitrariness of the sign. Given my approach to memes, that arbitrariness would appear to eliminate the possibility that word meanings could have memetic status. For, as you may recall, I’ve defined memes to be perceptual properties – albeit sometimes very complex and abstract ones – of physical things and events. Memes can be defined over speech sounds, language gestures, or printed words, but not over the meanings of words. Note that by “meaning” I mean the mental or neural event that is the meaning of the word, what Saussure called the signified. I don’t mean the referent of the word, which, in many cases, but by no means all, would have perceptible physical properties. I mean the meaning, the mental event. In this conception, it would seem that that cannot be memetic.

That seems right to me. Language is different from music and drawing and painting and sculpture and dance, it plays a different role in human society and culture. On that basis one would expect it to come out fundamentally different on a memetic analysis.

This, of course, leaves us with a problem. If word meaning is not memetic, then how is it that we can use language to communicate, and very effectively over a wide range of cases? Not only language, of course, but everything that depends on language. Continue reading “In Search of the Wild Replicator”

Social structure and language evolution: resolving the synthetic/analytic debate

A cultural evolution approach to language suggests that genes encode weak prior biases that can be amplified through cultural transmission to produce strong language universals. Below is a diagram from Kirby, Dowman & Griffiths (2007).

The link between biological predispositions and language structure, from Kirby, Dowman & Griffiths, 2007.

Note the long-term feedback between language universals and genes. However, recent research is pointing towards a more complicated picture. Continue reading “Social structure and language evolution: resolving the synthetic/analytic debate”

Deictic Gestures in Ravens

Ravens can point. It’s scary how clever birds can be.

Guys! Guys! Guys!

Ravens can point. It’s scary how clever birds can be. People keep sending me this paper so I thought I’d link to it here so that people know I’ve seen it and stop bothering me (I actually don’t mind being bothered, especially if it’s about interesting things like this, please don’t stop). Abstract below.

Around the age of one year, human children start to use gestures to coordinate attention towards a social partner and an object of mutual interest. These referential gestures have been suggested as the foundation to engage in language, and have so far only been observed in great apes. Virtually nothing is known about comparable skills in non-primate species. Here we record thirty-eight social interactions between seven raven (Corvus corax) dyads in the Northern Alps, Austria during three consecutive field seasons. All observed behaviours included the showing and/or offering of non-edible items (for example, moss, twigs) to recipients, leading to frequent orientation of receivers to the object and the signallers and subsequent affiliative interactions. We report evidence that the use of declarative gestures is not restricted to the primate lineage and that these gestures may function as ‘testing-signals’ to evaluate the interest of a potential partner or to strengthen an already existing bond.

If you’re interested in reading about referencial gestures in humans and chipanzees and why these things are relevant to the evolution of language you should read Michael’s post here.

Never mind language, emotions are in a category of their own

A new paper in the journal ‘Emotion’ has presented research which has implications for the evolution of language, emotion and for theories of linguistic relativity.

A new paper in the journal ‘Emotion’ has presented research which has implications for the evolution of language, emotion and for theories of linguistic relativity. The paper, entitled ‘Categorical Perception of Emotional Facial Expressions Does Not Require Lexical Categories’, looks at whether our perception of other people’s emotions depend on the language we speak or if it is universal. The results come from the Max Planck Institute for Psycholinguistics and Evolutionary Anthropology.

Human’s facial expressions are perceived categorically and this has lead to hypotheses that this is caused by linguistic mechanisms.

The paper presents a study which compared German speakers to native speakers of Yucatec Maya, which is a language which has no labels which distinguish disgust from anger. This was backed up by a free naming task in which speakers of German, but not Yucatec Maya, made lexical distinctions between disgust and anger.

The study comprised of a match-to-sample task of facial expressions, and both speakers of German and Yucatec Maya perceived emotional facial expressions of disgust and anger, and other emotions, categorically. This effect was shown to be just as significant across the language groups, as well as across emotion continua (see figure 1.) regardless of lexical distinctions.

The results show that the perception of emotional signals is not the result of linguistic mechanisms which create different lexical labels but instead shows evidence that emotions are subject to their own biologically evolved mechanisms. Sorry Whorfians!

References

Sauter DA, Leguen O, & Haun DB (2011). Categorical perception of emotional facial expressions does not require lexical categories. Emotion (Washington, D.C.) PMID: 22004379

Chomsky on Language Evolution

Learning new skills is a fascinating process that often involves a complex interplay between biological predispositions and cultural transmission. The evolution of language, in particular, has captivated scholars and researchers, leading to intriguing debates surrounding its origins and development. Recently, esteemed linguist Noam Chomsky delivered a thought-provoking lecture at UCL, where he discussed the poverty of the stimulus and critiqued iterated learning experiments. These experiments, which explore language evolution and artificial language learning, have sparked discussions about the role of human intelligence and the nature of evolutionary processes. As the field of communication evolution continues to evolve, new avenues such as government compliant LMS offer promising opportunities to enhance our understanding of how skills are acquired and disseminated.

Noam Chomsky gave a lecture on the poverty of the stimulus at UCL responding to topics such as language evolution and artificial language learning experiments. From about 89 minutes in he discusses iterated learning and language evolution, saying the conclusions derive from “serious illusions about evolution”:

Chomsky’s criticism of iterated learning experiments (see post here and here) is based on two points. First, the emergence of structure is more to do with the intelligence of the modern humans taking part in the experiment than a realistic language evolving scenario. He suggests that structure would not emerge in a series of computer programs without human intelligence. As as a colleague pointed out, however, the first iterated learning experiments used computational models of this kind. Secondly, he suggests that the view of evolution employed in the explanation of these systems is a pop-psychology, gradual hill-climbing one. In fact, Chomsky claims, evolution of traits such as language or eyes derive from single, frozen accidents. That is, evolution moves in leaps and bounds rather than small steps (Jim Hurford recently gave a lecture entitled ‘Reconciling linguistic jerks and biological creeps‘ on this topic). Why else would humans be the only species with language?

Geoffrey Pullum counters this last point by asking why would an innately specified UG emerge so rapidly, but then freeze for tens of thousands of years, when (borrowing Phillip Lieberman’s point) traits such as lactose tolerance have emerged in the human genome within two thousand years. Chomsky gives some examples of traits that have developed rapidly, but then only changed marginally.

I don’t think that proponents of iterated learning paradigms would have a problem with a sudden emergence of a capacity for advanced linguistic communication. Although there is a continuity between human and non-human communication systems, we have some tricks that other animals don’t (see Michael’s post here). However, the evolution of the structure of language after these mutations could owe a huge amount to processes of cultural transmission. The universals we see in the world’s languages, then would be an amplification of weak biological biases.

However, Chomsky seems disillusioned with the whole field of what he calls ‘the evolution of communication’. At least we didn’t get it as bad as exemplar theory, which he dismisses as “so outlandish it’s not worth thinking about”.

[Edit: I originally attributed Mark Liberman instead of Phillip Lieberman. Now I’ve made this error in both directions!]

Language Evolution Session at EHBEA 2012

H/T: Evolutionary Linguistics.

Call deadline: 25 November 2011
Event Dates: 15-28 March 2012
Event Location: Durham, UK
Event URL:
http://www.dur.ac.uk/jeremy.kendal/EHBEA2012/Welcome.html
Dear colleagues,

We are organising a special themed session on language evolution at the 2012 Annual Meeting of the European Human Behaviour and Evolution Association, which is held in Durham, UK, 25th-28th March 2012 (http://www.dur.ac.uk/jeremy.kendal/EHBEA2012/Welcome.html). EHBEA is an excellent venue for interdisciplinary work on the cultural and biological evolution of human behaviour, including language. Given that EHBEA is running shortly after EVOLANG next year, we are happy for research that is targeted at EVOLANG to also be submitted here, although note that the audience for each is likely to be different.

If you would like to submit an abstract for consideration as part of this themed session, please follow the submission instructions on the EHBEA website, marking your abstract as for consideration in the language evolution special session, organised by Simon Kirby and Kenny Smith. Abstracts will be independently reviewed by the usual EHBEA reviewers, so bear that in mind when preparing your submission. The themed session will only run if sufficient abstracts are accepted – of course, papers on language evolution could be presented independently as standard EHBEA talks.

The deadline for submissions is November 25th.

PLEASE FORWARD THIS MESSAGE TO ANYONE WHO MIGHT BE INTERESTED!

Best wishes,
Simon & Kenny