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Takahashi et al (2013) Coupled Oscillator Dynamics of Vocal Turn-Taking in Monkeys
Borjon & Ghazanfar (2014) Convergent evolution of vocal cooperation without convergent evolution of brain size.
Please don't forget that your blog comments are due at 9am on the day of the seminar!!!
I found the reduction to oscillators in the Takahashi paper to be an intriguing move. Aside from the fact that this concept has made its way to philosophy in attempts to explain representations, it leads to the interesting conclusion, seemingly reached by the authors on page 2165, that the difference between non-human apes and humans is a difference of degrees, not kind. While it might be true that humans have cognitive capabilities of a different kind that apes, it only leads to a difference of degree in the kind of cooperative communication.
ReplyDeleteIn the other article, I found the claim that evolutionary pressure exert forces, not simply on neuronal substrates, but on the whole individual to be of interest. While maybe this is new to the realm of philosophy and classical cognitive psychology, which has focused simply on abstract, mental/neuronal processes, it is definitely something that has had a resurgence and increased interest in recent years. And it’s always nice when an evolutionary “fact” (not to underplay its legitimacy, but simply because I’m not sure if it’s a fact/theory/claim in the evolutionary world) coincides with a recent, underrepresented view in philosophy.
I really liked both of these papers, the cooperative vocal communication and the social learning in marmoset monkeys in particular. I was unfamiliar with couple oscillatory mechanisms.
ReplyDeleteI was interested in how this theory implies that vocalizations came before gestures. I would assume this assertion is based upon the observations of the marmosets, other primates, and the increased socio-cognitive abilities associated with not only cooperative communication but cooperative breeding. Is it that if cooperative vocal communication is scaffolded in arousal, it implies verbal vocalization due to these observations? I am not sure that I really grasped the unpacking of this argument in the second paper or for that matter the first.
I understand the concept of convergent evolution but I do not see how the presence of this mechanism implies a manual gesture or alternative possibility. Humans and marmoset share similar environments but could these concepts have occurred concurrently? Or is it more likely that it was one or the other? The evidence presented in this paper makes a good case for a different possibility. The marmosets experience greater learning opportunities through the biparental/alloparental parenting style. The whole notion that "it takes a village to raise a child." There is also the beneficial side effect that the second paper (p.6) states marmosets forage while carrying infants with them and that these infants were in turn less likely to consume items that they were unfamiliar with or did not see alloparents eating, which is a beneficial aspect of cooperative environments. This type of social learning would promote a better quality of life and survival. Also, cooperative breeding would require better signal quality and communication between sender and receiver to coordinate tasks.
1st paper- Takahashi et al.
Delete2nd paper- Borjon & Ghanzanfar
Just wanted to clarify which papers I refer to when I say first and second paper.
I want to point to a quote from the 2013 paper, page 2165:
ReplyDelete“This is not to argue that higher-order cognitive capacities like recognition, prediction, and/or understanding are not important for human conversations[29-31]; no doubt these play important roles guiding our conversations. However, they are not the sole criteria for cooperative communication… Marmoset vocal turn-taking may represent the kind of foundational scaffold upon which more sophisticated forms of communication were built in humans."
Turn-taking in both humans and marmosets seems to have an element of stress reduction at work. I see how grooming behavior is cooperative, and I see how turn-taking and conversations are cooperative. I think my question has to do with the scaffolding issue. Because there are these commonalities in cortisol reduction (possibly) in these behaviors, why would this lead to the inference that this basic cooperative element might be scaffolding for these other cognitive capacities? I don’t think that I want to say that these could exist without having this type of behavioral substrate, but I’d like a little more detail on what other intermediate capabilities might be involved in this. These higher level capacities don’t seem to be built on cooperative behaviors, but offer a different motivational aspect entirely, appealing to entirely different conceptions of consciousness and volition in both cases. Anyway, it's an interesting theory and I’d like to see it fleshed out a bit.
Each of these articles claim that the turn-taking communicative behaviour of marmosets constitutes an example of convergent evolution. I think I am a bit confused about this concept and whether or not this marmoset behaviour constitutes an example of it.
ReplyDeleteAs I understand it, convergent evolution involves two different animals using morphologically similar body parts in a functionally similar manner. For instance, a bat wing and a bird wing have a similar shape and are used for flying, but they have differing constitutive parts. What makes it a case of convergent evolution is that the closest common ancestor of bats and birds did not have the ability to fly, rather, birds and bats separately adapted to similar environmental selection pressures and developed analogous but not homologous body parts that perform analogous functions.
I am wondering whether similar turn-taking communicative behaviour in marmosets and humans is enough to constitute a case of convergent evolution in the absence of a clear cut analogous body-part. Borjon and Ghazanfar claim that similar brain size and shape for instance is totally unnecessary for such analogous behaviour. Rather, a simple neural circuit mechanism is responsible for each animal's (marmosets and humans) ability to function as one pole in a coupled oscillator dynamic in turn-taking behaviour.
SO here's my question. The first way I described convergent evolution involved a visible body part and the function it performs in an animal's behaviour. Here a behaviour (flying) is undergirded in two different animals by morphologically similar but differently composed body parts.
In the second case, In lieu of similar brains in humans and marmosets, convergent evolution involves a posited neural circuit mechanism - that is, the shape/size of the brain doesn't seem to matter so long as it functions in an analogous way. SO what we have is analogous behaviour (turn-taking) undergirded by an analogous function of physically non-similar neurons (a neural circuit mechanism). Is this still the same concept? Or are the authors challenging the way we think about convergent evolution?
The focus in both target articles on turn taking in conversation, as well as the utilization of a comparative research paradigm between humans and several other animals (including marmosets and rats, for instance) provides an important source of evidence for debates about the role of gesture as an evolutionary precursor to human vocal and communicative practices. Along these lines, I have two questions in relation to the Borjon & Ghazanfar article. While Takahashi et. al. reference the gestural hypothesis, the former article introduces it in a clear three-step formula (94). In light of this formulation, would it be possible to see some of the work present in the two target articles as fleshing out the third step - a "mysterious" transition from gestural to vocal communication - instead of offering an alternative to it? In other words, since there may have been similar evolutionary pressures present in both humans and marmoset monkeys that fostered vocal turn-taking, perhaps the first two steps for the gestural hypothesis provide the evolutionary story for explaining our distinct communicative practices as well as setting species-specific parameters in the evolutionary design space from which we evolved our unique set of neurological and morphological features, while the vocal and turn-taking component came about through a distinct set of evolutionary demands.
ReplyDeleteSecond, and in part dovetailing from the above considerations, while there are clear differences between the two hypotheses at play, such as the purported (lack of a) role for prior gestural communication skills as well as different demands in the realms of cognitive complexity and brain sizes for vocal turn-taking, is it at least in principle possible to unify elements of these hypotheses into a single hypothesis, as I suggested briefly above, or no?
One of major argument in this article is that considering their findings of oscillatory mechanism for vocal turn taking, traditional view of gestural based communication could be wrong. I can admit their suggestion on the basis of evidences shown in the article, but in order to be more persuasive and make convincing argument against people who insists gestural-origin of communication, it would be better to deal with their view and refute their claim. This thought may arise because I have no idea about the traditional assumption that cooperative vocal communication arouse after manual gesture.
ReplyDeleteIn this experiment set, they analyzed phee calls which are referred to long-distance contact calls by marmosets. It says that marmoset have a capacity of producing number of distinct vocalization produced in a number of different context. Then, why they used phee calls which just have a purpose of calling, rather than other diverse vocalization, in which may deliver particular meaning, they can produce.
I really liked these articles. It seems like an important move to place the origin of language in the vocal interaction itself, rather than trying to tell as story about how the capacity to use and manipulate vocal signs thereby led to interactive communication practice. The latter seems to be sort of putting the cart in front of the horse.
ReplyDeleteHowever, it’s difficult to see how turn taking can come onto the scene unless that practice were used to communicate information. I might be missing some content in these articles, but I’m having a hard time seeing what is motivating these turn taking practices if it’s not some sort of meaningful exchange practice. But they appear to be saying there is just a coupled turn taking of vocal behavior. Doesn’t the motivation to couple vocal behavior come from informational exchange? Or the just saying that this is an instinctive urge that appears among some prosocial animals with certain kinds of anatomical affordances?
It’s interesting to see that marmosets showed turn-taking behaviors like humans do and it is another counter example of the gestural-origins hypothesis. These calls may be used in two ways: arousal reduction and information extraction, but are they still more like fixed signals? Has this turn-taking behavior seen in baby marmosets as well? Do they have to learn how to produce these phee calls and the turn-taking behavior?
ReplyDeleteStudies by Borjon and Ghazanfar and by Takahashi et al. both compare turn taking in vocalizations of marmosets with turn taking among humans. Takahashi et al. focus on the time intervals of marmoset vocalizations, considering whether the apparent quality of non-overlap could be explained by chance, by a reset mechanism as found in chorusing frogs, or by another suppression factor. They conclude that marmoset vocalization behavior is best explained by a coupled oscillation model, also used to model human turn-taking behaviors. They find that the wait time between turns is significantly longer for marmosets, around 5 seconds, while for humans it is measured in milliseconds. A proposed explanation for this difference is the difference in the lengths of meaningful units of expression.
ReplyDeleteBorjon and Ghazanfar focus on the contrasting evolutionary development of humans versus marmosets. Marmosets are distant relatives of humans but did not develop the large brain size which humans have. Borjon and Ghazanfar propose a neural circuit mechanism that may explain turn-taking as a result of ‘vocalization-induced reductions of arousal,’ or a calming effect of speech. They propose that this mechanism may have affected the development of both human and marmoset turn-taking, though developing independently in each species.
The argument that turn-taking does not necessarily require higher order brain function seems interesting. My question would be the time scale difference on turn-taking between marmosets and humans. It was suggested why the difference may occur, yet if the authors applied "units of perception" to explain the time scale difference, it seems that higher order brain function may be inlvolved to some extent which would be contradictory to their argument.
ReplyDelete