Communication in Bonobos, Chimpanzees, and the Evolution of Language

The current issue of First Language features some interesting articles on the evolution of language:

It includes a book review of Michael Tomasello's "Origins of Human Communication" by Evan Kidd as well as a review of an edited volume titled "The Evolution of Human Language: Biolinguistic Perspectives" by Thomas Scott-Phillips, who rightly argues that the term Biolinguistics - which is mainly used by people from the Generative Grammar camp - is "not a theory-neutral term for the study of language origins."

Last but not least, there's also an interesting article by Heidi Lyn, Patricia Greenfield and E. Sue Savage-Rumbaugh about "Semiotic combinations in Pan: A comparison of communication in a chimpanzee and two bonobos."

Here's the abstract:

Communicative combinations of two bonobos (Pan paniscus) and a chimpanzee (Pan troglodytes) are compared. All three apes utilized ordering strategies for combining symbols (lexigrams) or a lexigram with a gesture to express semantic relations such as agent of action or object of action. Combinatorial strategies used by all three apes revealed commonalities with child language, spoken and signed, at the two-year-old level. However, many differences were also observed: e.g., combinations made up a much smaller proportion and single symbols a much larger proportion of ape production compared with child production at a similar age; and ape combinations rarely exceeded three semiotic elements. The commonalties and differences among three sibling species highlight candidate combinatorial capacities that may underlie the evolution of human language.

Review of FOXP2 and its role in brain development, speech, and the evolution of language

Edmund Blair Bolles over at Babel's Dawn discusses a very interesting review of "FOXP2 and the role of cortico-basal ganglia circuits in speech and language evolution" by Wolfgang Enard. Be sure to check it out!

Below you can find the abstract of the review:

"Purpose of the review

A reduced dosage of the transcription factor FOXP2 leads to speech and language impairments probably owing to deficits in cortical and subcortical neural circuits. Based on evolutionary sequence analysis it has been proposed that the two amino acid substitutions that occurred on the human lineage have been positively selected. Here I review recent studies investigating the functional consequences of these two substitutions and discuss how these first endeavors to study human brain evolution can be interpreted in the context of speech and language evolution.

Recent findings

Mice carrying the two substitutions in their endogenous Foxp2 gene show specific alterations in dopamine levels, striatal synaptic plasticity and neuronal morphology. Mice carrying only one functional Foxp2, show additional and partly opposite effects suggesting that FOXP2 has contributed to tuning cortico-basal ganglia circuits during human evolution. Evidence from human and songbird studies suggest that this could have been relevant during language acquisition or vocal learning, respectively.

Summary

FOXP2 could have contributed to the evolution of human speech and language by adapting cortico-basal ganglia circuits. More generally the recent studies allow careful optimism that aspects of human brain evolution can be investigated in model systems such as the mouse.

Highlights

► First functional studies investigate human FOXP2 evolution in a mouse. ► Human-specific properties of FOXP2 are specific to cortico-basal ganglia circuits. ► These properties might be relevant for language acquisition and/or vocal learning."

The need for multimodality in primate communication research

Barbara King points to a very interesting article in press at Animal Behaviour. In their essay "The language void: the need for multimodality in primate communication research" Katie Slocombe, Bridget Waller and Katja Liebal analyse more than 550 studies on primate communication from 1960 to 2008 and argue that research in one modality (e.g. gesture) often differs so strongly in its methodology from research on another modality (e.g. alarm calls) that the results can hardly be reliably compared. Here's their abstract:

Theories of language evolution often draw heavily on comparative evidence of the communicative abilities of extant nonhuman primates (primates). Many theories have argued exclusively for a unimodal origin of language, usually gestural or vocal. Theories are often strengthened by research on primates that indicates the absence of certain linguistic precursors in the opposing communicative modality. However, a systematic review of the primate communication literature reveals that vocal, gestural and facial signals have attracted differing theoretical and methodological approaches, rendering cross-modal comparisons problematic. The validity of the theories based on such comparisons can therefore be questioned. We propose that these a priori biases, inherent in unimodal research, highlight the need for integrated multimodal research. By examining communicative signals in concert we can both avoid methodological discontinuities as well as better understand the phylogenetic precursors to human language as part of a multimodal system.

Barbara King's discussion of the article is also very illuminating.

Edmund Blair Bolles Blogging about the 2010 Evolution of Language Conference

Over at Babel's Dawn Edmund Blair Bolles has started blogging on the 2010 Evolution of Language Conference in Utrecht, the Netherlands.

- his first critical discussion of Maggie Tallerman's talk defending the sense of a partly-language-specific innate 'language faculty' can be found here.

In her talk, Tallerman mentioned that some of Chomsky's recent ideas on 'third factor principles,' physical laws, and general cognitive principles playing a part in constituting language are actually quite similar to people who criticize generativism.

I had the same impression after attending a talk Noam Chomsky gave a few weeks ago in Mainz, Germany. In the Q&A section there he even spoke of the importance of social factors like 'Theory of Mind' in the evolution or rather the evolutionary transmission of language once the cognitive property of 'merge' had been externalized linguistically.

I'm really interested in what the other people at the conference will say about Tallerman's talk so I'll stay tuned.

Update:

Bolles' other posts on the conference, which are based on the slides the presenters sent to him in advance, can be found here:

- Terrence Deacon's talk

- Peter Gardenförs' talk

- Stephen Anderson's talk

- Morten Christiansen' talk

Biolinguistics, Cooperation, the Importance of Theory of Mind for Language - and Dinosaurs

Some interesting links:

• The journal "Biolinguistics" now has a blog (here). On it they want to post "a variety of material pertaining to the field of biolinguistics." As of now there isn't very much content other than some information on conferences but I'll stay tuned.

• On a related note, Julia Fischer of the Cognitive Ethology Laboratory at the German Primate Center in Göttingen, Germany has written a short review of Michael Tomasello's book "Why We Cooperate." I've written a short summary of the slim volume myself, but I seem to have msiplaced the document... Anyway, this review is by somebody who really knows the stuff and is quite enlightening.

• Also, over at Babel's Dawn there is an interesting discussion of a paper by David Leavens and Tim Racine (abstract here) that questions whether it is really justified to attribute sophisticated psychological processes to preverbal infants in the way Michael Tomasello and many others do. Instead, they argue that learning and growing up in a human community play a much more important part that is normally acknowledged (first part here, second part here). Edmund Blair Bolles thinks that the argument has some merit but remains sceptical. In the comment section of his first post, the authors themselves weigh in.

• Lastly, and not really relatedly, I really like this cartoon:
hat tip: Richard Beck

New York Times Article on the Evolution of Language

There's a nice New York Times story by Nicholas Wade called "Deciphering the chatter of monkeys" that deals with the evolution of language. As Edmund Blair Bolles points out, it misses many things that are important about the topic but still its a comparatively good and well-written popular article.

Be sure to check out Mark Liberman's short discussion of the article here. He writes that it is a "remarkably good article, in comparison to many that I've seen on similar topics," which may or may not be a real compliment :)

Hat tip: Babel's Dawn, Language Log

Combinatorial Structure in Monkey Vocalizations

Both John Hawks and Babel's Dawn link to an interesting article in the New York Times that reports on an as of yet unpublished paper by Klaus Zuberbühler and his colleagues on combinatorial (syntax-like) structure in the calls of Campbell's Monkeys:

"If the Zuberbühler team’s observations are correct, the Campbell’s monkeys can both vary the meaning of specific calls by adding suffixes and combine calls to generate a different meaning. Their call system, the researchers write, “may be the most complex example of ‘proto-syntax’ in animal communication known to date.”"

From Zuberbühler's previous work (e.g. Zuberbühler 2002, Zuberbühler 2006) it was already clear that some monkey species have very limited degree of flexibility in combining the vocalizations, but the fact that the combinatorics seem to be more complex than thought before seems quite interesting.

P.S.: Ed Yong also has a nice write-up

Studying the Evolution of Cognition and Language: Are We Wasting Our Time? (Part 2)

In my last post I discussed some of the criticisms faced by people interested in the evolution of cognition.
One of the harshest critics is Richard Lewontin, who, at the end of his article "The Evolution of Cognition: questions we will never answer", advises his readers to “

to give up the childish notion that everything that is interesting about nature can be understood. History, and evolution is a form of history, simply does not leave suffcient traces, especially when it is the forces that are at issue. Form and even behavior may leave fossil remains, but forces like natural selection do not. It might be interesting to know how cognition (whatever that is) arose and spread and changed, but we cannot know. Tough luck.. (Lewontin, 1998: 130).”

But what leads Lewontin to conclude his essay in such as pessimistic and definitive manner?
According to Lewontin, there are three main strains of evolutionary explanations. And with each strain there are problems with evolutionary inquiries into cognition.

Historical Explanations
Firstly, there is a strain that explains the patterns of similarities and differences between animals through historical relatedness. Humans, for example, are more similar to and share more traits with chimpanzees than with lemurs because the human/chimpanzee lineages split some 5-7 million years ago and the lemur/human lineage split some 78 million years ago.

Functional Explanations
Secondly, there is a strain that tries to explain these patterns by looking at the functions they perform and the adaptive advantage they may have. The bodily similarities of sharks, dolphins, seals, and penguins for example can be explained by the fact that their bodies are adapted to swimming in the sea. Similarly, the differences between closely related species can be explained by adaptations to different environments. The differences between cows, goats, and deer, for example, only arose in the last 10 million years due to the different environments they had to adapt to. (Lewontin 1998: 116).

Problems for Studying the Evolution of Cognition
This is of course a problem for studying the evolution of cognition. Chimpanzees are the closest relatives that still exist but we and them may both have diverged so far from our ancestors that studying the cognitive differences between us may not really give us an insight into much human evolution. Indeed, there even is a study claiming “

more genes underwent positive selection in chimpanzee evolution than in human evolution.” (Bakewell et al. 2007).

Overall,

“Humans and chimpanzees are nevertheless very similar in their proteins, on the average, but vastly different in the sizes of their brains and their ability to write books about each other.” (Lewontin, 1998: 117).

But here is a point where I disagree with Lewontin: the research shown earlier indeed indicates that there probably was not a large amount of changes in brain-related genes that led to human cognition:

“This conclusion, however, does not preclude the possibility that substantial accelerations occurred in the evolution of a few nervous system genes during human origins. Indeed, several such examples are known, including genes that control brain size and speech development. (Shi et al. 2006).

And indeed, a recent article based on assumptions similar to that of these researchers and Lewontin, by Derek Penn and his colleagues, (2008) doesn’t see things so negatively as Lewontin but instead sees these considerations as offering a great chance.

If there really is “profound functional discontinuity between human and nonhuman minds” we can ask if there is a core ability that is responsible for it.
For Penn et al. psychological, comparative and developmental studies point towards the conclusion that this cognitive cap

“is largely due to the degree to which human and nonhuman minds are able to approximate the higher-order, systematic, relational capabilities of a physical symbol system.”

Sara Shettleworth (2009), in her critique of Bolhuis & Wynne’s (2009) arguments which are quite similar to that of Lewontin, agrees that

“There is evidence from behavioural studies that many of humans' mental powers are shared by other animals, including simple forms of learning, memory and categorization, and the elements of social, spatial and numerical cognition.
Only against this background does it make sense to propose, as some have, that there is a distinct small set of mental powers that is unique to humans […].”

Other researchers also defend the view that, contrary to Lewontin, we can learn a lot about the evolution of primate and human cognition by comparing different extant species. Jonathan Kenneth Burns (2004), for example, directly attacks Lewontin's arguments in an article on the evolution of Schizophrenia by stating that primatologist Richard Byrne

“has listed the establishing of a reliable pattern of descent as one part of a methodology for inferring the history of primate cognition (Byrne 2000). Many authors have confirmed the close evolutionary relationship between simian and ape species and modern Homo sapiens, with strong data from comparative psychology, molecular biology, and physical anthropology. Thus, cladistic analysis provides us with living relative species with which we can test the hypothesis that there is a heritable variation for social cognition that increases fitness.“ (Burns 2004: 868)

Evolutionary Constraints
But back to Lewontin’s article. The third strain of evolutionary theory he mentions is the one focusing on developmental and physiological constraints in the evolution and development of organisms. In the billion years of vertebrate evolution, for example, no organism ever developed more than four limbs.
Equally, mammals that went back into the sea and became whales and seals, the turned their limbs into flippers and flukes, but still retained their basic mammalian skeletal architecture.
This probably means that there are basic biological constraints because the available material regulates which evolutionary changes are possible, although the functions and activities of organisms and their parts may change quite dramatically over evolutionary time.
It also implies that

“when new functions arise in evolutiom, they often do so through a process of recruiting previously existing organs or physiological activities.” (Lewontin 1998: 117).

But If a trait is unique to one species it may be that we can’t really find any direct precursors and that it thus has no real “observable evolutionary history.”
What is more, we can’t be sure if a similar trait in other species it is far from clear if

"we are dealing with the same trait in the genetic, anatomical, and physiological sense.” (Lewontin 1998).

Platforms for the evolution of human cognition
I would argue however, that studies that show that similar cognitive activities which activate and rely on similar neural systems are a strong candidate for homologous platforms for human cognitive evolution. In fact, we now know that there are strong neural similarities between aspects of the macaque conceptual system and the human once (Gil-da-Costa et al. 2004).
With research like this we can thus probe into the “common architecture” that “underlies the conceptual systems of different species”, and ask how “additional systems” may have extended “human conceptual abilities significantly” (Barsalou 2005).
We also know now that “Communicative Signaling Activates ‘Broca’s’ Homolog in Chimpanzees,” and recent comparative neuroimaging studies have given new and important insights into the evolution of specialized language areas in human evolution. (for a great summary see this post).

Concluding Remarks
These examples lead me to think that we can learn a lot about the evolution of human cognition and language if we draw together the massive amount of data on the subject from all the different disciplines in a coherent and sensible manner. We simply have much more data to work with than at the time Lewontin voices his criticisms. Studying the evolution of cognition is – or has become – more than a ‘Paleofantasy’ in which we simply tell stories because we don’t know enough. Quite to the contrary – often it is the incredible wealth of data from different disciplines that presents the biggest problem.
Sverker Johansson's (2005) gargantuan collection of data relevant to the study of language evolution bears testament to this. The Study of language evolution, after it has moved beyond its ‘adaptationist’ beginnings in the early to mid-nineties – which Lewontin rightly criticized in some respects – is still a developing and growing field and I certainly agree with Willem Zuidema (2005) who states that

“Only when we have precise scenarios of the evolution of language and worked out ways to test empirically the plausibility of one scenario against another, can we conclude . if that turns out to be the case that there are too many alternative scenarios consistent with the available data. In my view, we have certainly not reached this stage yet.”

I hope I can wrap up my discussion of Lewontin's article next week.

References:

Bakewell,Margaret A., Peng Shi, and Jianzhi Zhang (2007:) More genes underwent positive selection in chimpanzee evolution than in human evolution. PNAS 104: 7489-7494.

Barsalou, Lawrence W. 2005. “Continuity of the conceptual system across species.” Trends in Cognitive Science 9.7: 309-311.

Bolhuis, Johan and Clive D. L. Wynne (2009):Can evolution explain how minds work?' Nature 458: 832–833.

Burns, Jonathan Kenneth. (2004) An evolutionary theory of schizophrenia: Cortical connectivity, metarepresentation, and the social brain. Behavioral and Brain Sciences
27(6):831–55; Discussion, 855–85.

Byrne, Richard W.(2000) Evolution of primate cognition. Cognitive Science 24(3):543–70

Gil-da-Costa, Ricardo, Allen Braun, Marco Lopes, Marc D. Hauser, Richard E. Carson, Peter Herscovitch and Alex Martin. 2004. “Toward an evolutionary perspective on conceptual representation: Species-specific calls activate visual and affective processing systems in the macaque.” PNAS 101.50: 17516–17521.

Johansson, Sverker (2005): Origins of Language: Constraints on Hypotheses. Amsterdam: Benjamins.

Lewontin, R. C. (1998) The evolution of cognition: Questions we will never answer. In D. Scarborough and S. Sternberg, editors, An invitation to cognitive science, Volume 4: Methods, models, and conceptual issues. Cambridge, MA: MIT Press

Shettleworth, Sara J. (2009). Cognition: theories of mind in animals and humans. In: Nature 459: 506.

Shi, Pen Margaret A. Bakewell and Jianzhi Zhang(2006):Did brain-specific genes evolve faster in humans than in chimpanzees? Trends in Genetics 22: 608-613.

News on FOXP2

There are some interesting posts on new work done on FOXP2. The human version of the gene, which is implicated in vocal coordination and language in some way among a lot of other functions, was inserted into mice who also possess a version of foxp2 that influences, among other things, erly ultrasonic vocalizations. The brain led to changes in neural organization but otherwise bodily development was normal. One implication of this is that the changes in the human version of FOXP2 probably affect neural development, which is quite an ecxiting find.

There are posts on the paper by Enard et al. over at:

Anthropology.net

Gene Expression

The Loom

Update:

Ed Yong of Not Exactly Rocket Science also has a nice post up on the topic

Six Candidates for What Makes Human Cognition Uniquely Human

One of the key candidates for what makes human cognition unique is of course language and symbolic thought. We are “the articulate Mammal” (Aitchison 1998) and an “animal symbolicum” (Cassirer 2006: 31). And if one defining feature truly fits our nature, it is that we are the “symbolic species” (Deacon 1998). But as evolutionary anthropologists Michael Tomasello and his colleagues argue, “saying that only humans have language is like saying that only humans build skyscrapers, when the fact is that only humans (among primates) build freestanding shelters at all” (Tomasello et al. 2005: 690).

Language and Social Cognition

According to them and many other researchers, language and symbolic behaviour, although they certainly are crucial features of human cognition, are derived from human beings’ unique capacities in the social domain. As Willard van Orman Quine pointed out, language is essential a “social art” (Quine 1960: ix). Specifically, it builds on the foundations of infants’ capacities for joint attention, intention-reading, and cultural learning (Tomasello 2003: 58). Linguistic communication, in this view, is essentially a form of joint action rooted in common ground between speaker and hearer (Clark 1996: 3 & 12), in which they make “mutually manifest” relevant changes in their cognitive environment (Sperber & Wilson 1995). This is the precondition for the establishment and (co-)construction of symbolic spaces of meaning and shared perspectives (Graumann 2002, Verhagen 2007: 53f.). These abilities, then, had to evolve prior to language, however great language’s effect on cognition may be in general (Carruthers 2002), and if we look for the origins and defining features of human uniqueness we should probably look in the social domain first.

Corroborating evidence for this view comes from comparisons of brain size among primates. Firstly, there are significant positive correlations between group size and primate neocortex size (Dunbar & Shultz 2007). Secondly, there is also a positive correlation between technological innovation and tool use – which are both facilitated by social learning – on the one hand and brain size on the other (Reader and Laland 2002). Our brain, it seems, is essential a “social brain” that evolved to cope with the affordances of a primate social world that frequently got more complex (Dunbar & Shultz 2007, Lewin 2005: 220f.). Thus, “although innovation, tool use, and technological invention may have played a crucial role in the evolution of ape and human brains, these skills were probably built upon mental computations that had their origins and foundations in social interactions” (Cheney & Seyfarth 2007: 283).

Language, Mental Representations, and Symbolic Thought

But this of course does not mean that we expect all other unique aspects of human cognition to be derivative of social cognition. The development of higher social cognition only presented the enabling context and cognitive starting point for other human mental capacities to evolve. To pick up the example again, language, for instance, does not only have an interactive function but also a symbolic one. It creates ‘symbolic assemblies’ that function as form-meaning pairings (Evans & Green 2006: 6f.). But the ability to acquire arbitrary symbolic units itself does not appear to be uniquely human, as it has been demonstrated in great apes, parrots, dolphins and dogs (see Tomasello 2008: 254ff.). But there are two essential differences between the symbolic abilities of humans and other animals: First, even with lexigram- or sign language-trained apes there appears to be nothing that even comes close to the production and joint engagement skills possessed by human children (production) or even pre-verbal infants (joint engagement) (Tomasello 2008: 109ff.).

Secondly, human symbols and concepts function as ‘decoupled representations’ which are not directly bound to a reaction pattern as in most other animal species, including symbol-trained animals, and enable significant “response breadth” and planning (Sterelny 2003: 29f.). In addition, symbolic thought and linguistic usage does not only rely on the comprehension and production of arbitrary signs, but essentially depends on our capacity for abstract, relational, analogical, higher-order, hierarchical and role-governed compositional thought. (Deacon 1998, Jackendoff 2007, Penn et al. 2008).

We now have two tentative candidates for what makes us special:

(1) The capacity to develop a shared point of view or “we-perspective” (Tuomela 2007: 46f.) and jointly engage in and attend to shared goals, plans and intentions in a cooperative collaborative activity within a joint attentional frame and a shared frame of reference (Tomasello et al. 2005).

(2) A conceptual system that is able to reinterpret and re-describe sensory as well as cognitive data and store them in an abstract, decoupled format that can be used for symbolic, relational and analogical reasoning (Penn et al. 2008).

We can now imagine a step in evolution where these two capacities were further integrated, yielding the analogical realization that others are “like me” (the capacity developed to

(3) actively attribute mental states to others in the same sense as one experience mental events and states oneself, that is to, have a “theory of mind” (Premack & Woodruff 1978).

Further, an integration of these capacities, and continuing collaborations and mutual engagements in social and other activities, would lead to the emergence of

(4) shared, intersubjectively overlapping frames of references or coordinate systems into which abstract and non-abstract conceptual representations could be integrated and imported in a systematic fashion, and within which shared percepts and concepts could be blended, unified, and related to each other in a role-governed fashion. (Bühler 1934, Fauconnier & Turner 2002).

In short, the first species in the hominin line who developed this capacity would not only have shared a perceptual world with his or her conspecifics, but they would inhabit a shared mental world. In this collective “we-perspective” and shared frame of reference mediated by joint engagement, they would then be able to create a shared “symbolic niche” in which meaningful cultural practices and shared symbolic constructs, such as institutions, could be co-created and which would ‘come alive’ and have actual real-world significance (Harder fc, Tuomela 2007). By jointly attending to and attaching meaning to cultural artefacts and practices homo gave them intersubjective value and reality and created ‘institutional realities’ (Searle 1995, Moll & Tomasello 2007). It is probable that from the dawn of human culture cognition accelerated in a spiralling and cumulative cognition-culture feedback loop

Additionally, when we are able to project ourselves and others into the same frame of reference, and can also project more abstract symbolic units into this coordinate system, it follows that along and co-evolving with these other changes a capacity

(5) for projecting ourselves and others backwards or forwards into past and future situations is probable to have evolved, that is, a capacity for mental time travel, including the ability to retrieve and re-live episodic memories of past autobiographical events (Tulving 2005) as well as prospective foresight enabling the planning of future actions and events (Suddendorf & Corballis 2007).

Finally, these changes were certainly accompanied co-evolutionary by a means of externalising shared proto-concepts and communicatively coordinating cooperative activities in a flexible manner via the vocal and gestural level. (Hurford 2007, Tomasello 2008). At some time, concepts became public, that is “they became the sorts of things that lots of people can, and do, share” (Fodor 1998: 28).

It is conceivable that “building upon pre-existing representational schemes in animals” (Hurford 2007: 140), and a general perceptual and cognitive machinery that scaffolded them (Jackendoff 2007: 388), ever increasing linguistic abilities and concepts evolved step by step. They probably did evolve from the proto-concepts we can see in the higher mammals of today into the pre-linguistic concepts that are argued to exist in some of the other great apes (especially those individuals who are enculturated and symbol-trained) and then into some form of proto-language (Bickerton 2009). At some time, this proto-language with already quite sophisticated conceptual representations then evolved into the fully human language we know today.

In summary, a truly human language faculty evolved, which is

(6) a collection of unique mental structures – phonology (externalisation) and syntax (merging constituents (A + B = [AB] and creating blended new ‘mental building blocks’ which can be merged with other constituents recursively [AB] + C = [ABC]) – and the interfaces between these mental structures and the conceptual system. These “specific unique building blocks for phonology, syntax, and their connection to concepts” are what makes language and language acquisition possible (Jackendoff 2007: 388f.).

This account of course has not mentioned important ecological factors (e.g. navigation, foraging, predator avoidance) that will have contributed to these developments and constructed niches in which these factors could develop further and faster. In the case of language, for example both “fast processing and mapping from hierarchical structure to temporal ordering,” which are two fundamentally important features of human language, “can be attributed to progresses in the timing of actions necessary for producing and using hand axes, [as well as throwing] that is, to sensomotoric skills that could have been adapted for language” (Wunderlich 2006). Support for this thesis comes from the fact that PET scans have shown a that there is neural circuitry supporting and involved in both language production and early stone age tool-making (Stout et al. 2008, see also here).

It also fits with our general model that there is mounting evidence “that much temporally sequenced hierarchical structure is constructed by the same part of the brain […] whether the material being assembled is language, dance, hand movements, or music (Jackendoff 2007: 388). Additional work on mirror neurons, motor neurons that activate both when an action is performed and observed (Rizzolatti & Craighero 2004), points in the direction that they are involved in understanding the goal-related actions of others in a social context. The evolution of a Mirror Neuron System for understanding actions and intentions may have been a crucial part of the cognitive development that made human thinking possible.

This is also supported by the fact that the human conceptual system has two distinctive properties: One the one hand it enables abstract, relational, role-governed, symbolic thinking (Penn et al. 2008). But at the same time human concepts are still deeply rooted in, based on, and grounded in embodied sensori-motor experience (Barsalou 1999, Gallese & Lakoff 2005). This holds even for linguistic concepts and metaphors, which have been shown to be partly grounded in embodied cognition (Lakoff & Johnson 1980). To get back to language, a final indicator of the connectedness of social interaction and parts of higher-order cognition comes from proposals that “neural circuits doing computations to control the hierarchy of goal-related actions were ‘exploited’ to serve the newly acquired function of language syntax” (Gallese 2007: 666).

Now that we have some theoretical proposals on crucial aspects of human uniqueness (although this list is far from being definitive and exclusive), we can see in how far they are borne out by the comparative and developmental data that is available.

References:

Aitchison, Jean. 1998. The Articulate Mammal. An Introduction to Psycholinguistics. London / New York: Routledge.

Barsalou, Lawrence W. 1999. “Perceptual Symbol Systems.” Behavioral and Brain Scienes 22.4: 577–609.

Bickerton, Derek (2009): Adams Tongue: How Humans Made Language. How Language Made Humans. New York: Hill and Wang.

Bühler, Karl (1934): Sprachtheorie: Die Darstellungsfunktion der Sprache. Stuttgart: Fischer.

Carruthers, Peter (2002), The cognitive functions of language, in: Behavioral and Brain Sciences, 25 (6),

657–726

Cassirer, Ernst (2006): An Essay on Man: An Introduction to a Philosophy of Human Culture. Hrsg. v. Maureen Lukay. Hamburg: Meiner (Gesammelte Werke. Hamburger Ausgabe. Band 23).

Cheney, Dorothy L. and Robert M. Seyfarth. (2007) Baboon Metaphysics: The Evolution of a Social Mind. Chicago: University of Chicago Press.

Clark, Herbert (1996): Use of Language. Cambridge: Cambridge University Press.

Deacon, Terrence William (1997). The Symbolic Species. The Co-evolution of Language and the Brain. New York / London: W.W. Norton.

Dunbar, R. I. M. and Susanne Shultz. (2007)“Evolution in the Social Brain” Science 317: 1344-1347

Evans, Vyvyan and Melanie Green (2006): Cognitive Linguistics: An Introduction. Edinburgh: Edinburgh University Press.

Fauconnier, Gilles and Mark Turner (2002) The Way We Think: Conceptual Blending and the Mind's Hidden Complexities. New York: Basic Books.

Fodor, Jerry A. (1998) Concepts. Where Cognitive Science Went Wrong. Oxford Congitive Science Series. Oxford: Clarendon.

Gallese, Vittorio (2007). Before and below 'theory of mind': Embodied simulation and the neural correlates of social cognition. Philosophical Transactions of the Royal Society B-Biological Sciences 362 (1480):659-669

Gallese Vittorio, Lakoff George (2005) The Brain’s Concepts: The Role of the Sensory-Motor System in Reason and Language. Cognitive Neuropsychology, , 22:455-479

Graumann, Carl F. (2002): Explicit and Implicit Perspectivity. In: Carl F. Graumann und Werner Kallmeyer (Eds): Perspective and Perspectivation in Discourse. Amsterdam, Philadelphia: John Benjamins Publishing Company, 25-40.

Harder, Peter (fc) Conceptual construal and social construction .

Hurford, James M. (2007): The Origins of Meaning: Language in the Light of Evolution. Oxford: Oxford University Press.

Jackendoff, Ray (2007): Linguistics in Cognitive Science: The State of the Art, The Linguistic Review 24, 347-401.

Lakoff, George, and Mark Johnson (1980) Metaphors we live by. Chicago: University of Chicago Press

Lewin, Roger (2005): Human Evolution: An Illustrated Introduction. Oxford: Blackwell.

Moll, Henrike, & Michael Tomasello. (2007) Co-operation and human cognition: The Vygotskian intelligence hypothesis. Philosophical Transactions of the Royal Society 362: 639-648.

Penn, Derek C, Keith J. Holyoak. and Daniel J. Povinelli (2008): Darwin's mistake: Explaining the discontinuity between human and nonhuman minds. In: Behavioral and Brain Sciences (31:2): 109-130.

Premack, David und Guy Woodruff (1978): Does the Chimpanzee have a

Theory of Mind? In: Behavioral and Bran Sciences 1: 515-526.

Reader, S.M. and K.N. Laland. 2002. “Social Intelligence, innovation, and enhanced brain size in primates” PNAS 99: 4436-4441.

Rizzolatti, Giacomo and Laila Craighero. “The Mirror-Neuron System.” Annual Review of Neuroscience 27 (2004): 169–192.

Searle, John R. (1995): The Construction of Social Reality. New York: Free

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Michael Tomasello - The Origins of Human Communication (summary pt. 3)

I wanted to finish this summary on the weekend but just didn't get round to it because I've got a lot to do right now. Here it is anyway:

Like I said in my last post, the rest of Chapter 2 focuses on what in the chimpanzee/human lineage provided a basis for modern language.

Pointing

One crucial factor is chimpanzees' ability to use and comprehend pointing.

In the wild, chimpanzee pointing is very rare. But approximately 60 to 70 percent of all captive chimps spontaneously use pointing in an imperative manner in their interactions with humans, e.g. by pointing to food that is out of reach as a request for the human to get it. But pointing gestures that aren't imperative are virtually absent. This even applies to language-trained apes such as Kanzi. In the few studies that have been done on this, 96-98 percent of all their pointing were imperative. The other 2-4 had no clear function.

Thus there is nothing in chimpanzees' pointing behavior that would suggest that they are capable of or interested in sharing attention within a joint attentional frame.

On the other hand, in a Brain Science Podcast interview, Stuart Shankar, co-author of The First Idea: How Symbols, Language, and Intelligence Evolved From Our Primate Ancestors to Modern Humans , reports of a an encounter he had with the bonobo Panbanisha in which she showed him various plants and classified them, for example, as poisonous. Shankar interprets this as truly sharing attention and informing for the the sake of informing, but Tomasello argues that these kinds of gestures are not to be seen as as truly declarative or informative, as they are more

„recognitory or classificatory, as the ape simply recognizes something and produces the associated sign in recognition“ (Tomasello 2008: 38).

Comprehending Pointing

Interestingly, chimpanzees are much worse comprehending other people's pointing than they are producing it themselves.

In a cool experiment, Tomasello and his colleagues have shown that in a cooperative situation, chimpanzees are unable to grasp the fact that the hidden food is in the bucket that the experimenter is pointing to. Human infants, on the other hand, are able to understand this task by 14 months of age. (Behne et al. 2005) In a competitive version of this task, however, chimpanzees fare much better (Hare & Tomasello 2005). These results suggest that chimpanzees have problems with "shared intentionality," i.e. recognizing situations where you have shared cooperative goals with others and have the same shared attentional frame.

Intentionality & Perception

According to Tomasello, apes and young human children both attribute simple forms of intentionality to other actors. For example, when a human repeatedly tries to give food to a chimpanzee but fails because he is clumsy, the chimp reacts patiently, whereas he gets frustrated when the human is failing to pass him the food for no good reason or because of unwillingness.

Most of the time enculturated chimpanzees also imitate

“demonstrator’s action more often when he freely chose his action than when he was forced to use it by some constraint” (Buttelman et al. 2007: F37, see here).

Crucially, chimpanzees also understand that others have perceptions and see things. In a competitive task with a dominant chimpanzee, for example, subordinate chimps, secretly take a food reward when the other one is unable to see him, but not when the food can be seen by the dominant chimp.

According to Tomasello then,

"The overall conclusion is thus that apes understand others in terms of their goals and perceptions and how these work to determine behavioral decisions, that is, they understand others as intentional, perhaps even rational, agents (Tomasello 2008: 4)

Intentionality + gestural fexibility = evolutionary foundations of language ?

This seems to be the conclusion Tomasello draws at the end of the second chapter. Clearly, when a chimpanzee produces a gesture, he does this in a very flexible manner that even shows sensitivity to the attention of the other. Ape vocalizations on the other hand are mostly inflexible and do not take into account the presence or absence of attention to the displays. Thus there is strong evidence that the capacities apes display in the gestural modality

"are the original font from wich the richness and complexities of human communication and language have flowed. " (Tomasello 2008: 55).

References:

Behne, T., Carpenter, M., and Tomasello, M. (2005). One-year-olds comprehend the communicative intentions behind gestures in a hiding game. Developmental Science, 8, 492–499.

Buttelmann, D., Carpenter, M., Call, J., and Tomasello, M. (2007). Enculturated apes imitate rationally. Developmental Science, 10, F31– 38.

Hare, B., and Tomasello, M. (2004). Chimpanzees are more skillful in competitive than in co-operative cognitive tasks. Animal Behaviour, 68, 571–581.

Tomasello, Michael (2008): The Origins of Human Communication. Cambridge, MA; London, England: MIT Press.

Charles Darwin & W. Tecumseh Fitch & Derek Bickerton on the Evolution of Language

Over at Language Log there are two very nice guest posts on the occasion of Darwin's 200th Birthday and his view of the evolution of language. The first post, by W. Tecumseh Fitch of St. Andrew's University, in which he reexamines Charles Darwin's proposal that the ancestors of humans first developed a emotionally expressive musical protolanguage which later developed into modern meaningful symbolic language. He discusses this view in the light of present-day evidence and concludes that

"suitably updated, [it] provides a compelling fit to both the phenomenology of modern music and language, and to a wealth of comparative data. "

He further argues that:

"This year of Charles Darwin's 200th birthday seems an opportune time for Darwin' own model of language evolution to regain the prominence it deserves."

In the second post, Derek Bickerton comments on Fitch's essay and critices his verdict that

"Darwin's view of language was ahead of its time, and his model and arguments remain surprisingly relevant."

Instead, he argues, although Darwin got a lot of things right,

"in many cases he was, inevitably, limited by the state of knowledge in his time."

In regards to the speculations on the evolution of language, Darwin's lack of knowledge about the ancestral environments of pre-humans ist the graves limitation.

In a savanna environment in which much of homo evolution supposedly took place, a musical, singing way of communication would simply be bizarre and even extremely dangerous because it would attract predators.

This is a problem Bickerton sees with a lot of theories of language evoltion. For example, he also critized the lack of regard for the environmental context of language evolution in a review of James Hurford's fantastic book, "The Origins of Meaning:"

"Hurford gives a favorable mention to niche construction theory, and I kept hoping he was going to draw the conclusion I drew from it: that the key to the origin of language must be sought somewhere among the niches constructed by human ancestors between the date of the last common ancestor of humans and other apes and the present—niches very different from any occupied by other apes. But he did not."

For Bickerton, Darwin, unknowingly, and Fitch, unwittingly, have made the same mistake:

"The notion of a terrestrial and heavily-predated primate indulging in any form of vocal activity-especially one that must, in quantity as well as quality, have exceeded those of all other primates barring gibbons-is simply bizarre,."

Both posts make for very interesting reading and I'm looking forward to the publication of both Bickerton's "Adam's Tongue" (out next month) and Fitch's book "The Evolution of Language" which apparently is in press as well.

Update: W. Tecumseh Fitch has replied to Bickerton's criticism with a post with the entertaining title ""Silence on the Savannah!" On Bickerton's Yodeling Australopithecines and Missing the Point of Musical Protolanguage"

Michael Tomasello - The Origins of Human Communication (summary pt. 2)

Wow. It has been quite some time since I've posted, and I'm sorry for that. I blame my essays and Boston Legal for it.

Anyway, here's the second part of my summary.

In the second chapter of his (2008) book, Michael Tomasello takes a look at the intentional communicative acts of non-human primates such as chimpanzees.

The question Tomasello asks is this: what are the psychological motives underlying these acts and in how much do they differ from those produced by infants?

Tomasello first differentiates between communicative displays and communicative signals.

Communicative displays are inflexible and involuntary, like a deer's horns or and or a peacock's tail, that deter competitors or attract mates, respectively. The important thing is that these displays are controlled by evolutionary processes over a long period tof time and not by the individual.

Communicative signals on the other hand, are produced, voluntarily and intentionally. The main characteristic of a communicative signal is that the communicator use it to influence the behavior of a single or multiple recipient(s). The communicator is thus actively directing his communicative signal at someone.

An interesting question now regards the famous alarm calls of some monkey species, e.g. the different alarm calls vervet monkeys make when they see a leopard, an eagle, or a snake.

Here's a video of vervet alarm calls, if you're interested:

As Tomasello points out, these calls are mostly involuntary and not very flexible.

The only flexibility regards the so called Audience Effect. This means that

“ individuals may not give certain calls when they are alone or without kin, as opposed to in the presence of others or with kin, but other animal species also refrain from alarm calling in these situations as well (including prairie dogs and domestic chickens; see Owings and Morton 1998), and so one may easily imagine that this is part of the genetically fixed adaptive specialization.“

In addition, there is evidence that cross-fostered macaque species are able to comprehend the signals of the other species, but not to produce it themselves.

Another important difference between human communicative signals and that of other primates is illustrated by the following example: when macaque mothers see (fake) „predators“ approach their offspring, they do not give an alarm calls when they themselves are not at risk (Cheney & Seyfarth 1990).

Vervet Monkeys too, mostly ignore the audience and continue giving alarm calls even when all other monkeys are in a safe position.

For Tomasello and other researchers this clearly shows that the vocalizations of non-human primates are not recipient-directed. Thus, they are to be judged as communicative displays.

Gestural signals, on the other hand, are much more flexible:

„individuals typically produce a gesture only when the recipient is appropriately attentive, and afterward they often monitor the recipient’s reaction and wait for a response;“ (Tomasello 2008: 21)

Also, ape gestures can be put into two broad categories: intention-movements and attention-getters.

In their social interactions, for example, chimpanzees raise their arms toward another chimp and start hitting her to initiate play or place their hand under her mouth and begin to take food to request food.

They also use gestures to get the others attention, for example by slapping the ground and looking at another chimp or by poking him or throwing stuff at him

Although we may find this behavior quite funny and daring to look at, it is still a remarkable fact that primates do this, as these kinds of gestures

„are not widespread in the animal kingdom; they may even be unique to primates or even great apes“ (Tomasello 2008: 27)

What is even more interesting that apes also string sequences of gestures together and combine both

attention-getters and intention-movements.

Although there is no evidence for a kind of „grammar“ for these sequence s (Liebal et al. 2004) it is still a very interesting phenomenon, especially as evidence for any combinatorial structure in primate vocalizations is confined to only two species (Zuberbühler 2002).

In summary, ape gestural communication is quite sophisticated and even has some kind of structure, even if its not something resembling the grammar of human language:

“check the attention of other > walk around as necessary > gesture > monitor the reaction of other > repeat or use another gesture.“

They are thus definitely to be judged as communicative signals.

Things such as attention and reaction monitoring seem to be an important part of the answer to the question

„What in the chimpanzee/human lineage provided a foundation for speech?“

And I will write a bit more about that in my next post.

References:

Cheney, D. L., and Seyfarth, R. M. (1990). Attending to behaviour versus attending to knowledge: Examining monkeys’ attribution of mental states. Animal Behaviour, 40, 742–753.

Liebal, K., Call, J., and Tomasello, M. (2004). The use of gesture sequences by chimpanzees. American Journal of Primatology, 64, 377–396.

Owings, D. H., and Morton, E. S. (1998). Animal Vocal Communication: A New Approach. Cambridge: Cambridge University Press.

Tomasello, Michael (2008): The Origins of Human Communication. Cambridge, MA; London, England: MIT Press.

Zuberbühler, Klaus (2002): A syntactic rule in forest monkey communication. In: Animal Behaviour 63, 293–299.