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LINGUAE-Primate Linguistics-Seminar-Spring 2013
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Research Seminar: Primate Linguistics (DEC B42)

Emmanuel Chemla (LSCP & Institut Jean-Nicod)

and Philippe Schlenker (Institut Jean-Nicod and New York University)

 LINGUAE Research Group

Spring 2013, Ecole Normale Supérieure

Schedule:

Tuesdays 4-6pm (unless otherwise noted). 1st session: February 12, 2013

- One 2 hour session a week, during 6 weeks

- Location: Room “INFO 1”, Ecole Normale Supérieure, 45 rue d’Ulm, 75005 Paris

- 3 ECTS

Note: The seminar will be given in English.

Requirements:

Weekly readings, active class participation (e.g. by way of class presentations), and a term paper.

Readings are available from: here.

Contact the instructors to obtain the login information.

Topic: Five striking results have emerged from studies of the vocalizations of non-human primates in the last thirty years.

1. Alarm calls sometimes have a referential semantics, i.e. they do not always encode a *level* of threat, but sometimes the *kind of predator* that triggers their occurrence (the species investigated include: vervet monkeys, Campbell's monkeys, Diana monkeys, among other; a pioneering article was Seyfarth and Cheney 1980). To give an example, Campbell's monkeys have a 'hok' alarm call which is usually used in the presence of eagles, while another alarm call, 'krak', is more commonly associated with leopards (Ouattara et al., PNAS, 2009b).

2. In some cases, a simple morphological structure appears to be available. Thus Campbell's monkeys have an '-oo' suffix which can appear after 'hok', 'krak' and 'wak' and appears to modify their meanings in what *might* be a regular way; in particular, the -oo modified calls appear to be used in situations of less immediate danger than the unmodified versions; and the 'krak-oo' call appears to function as a general alarm call (Ouattara et al., PNAS, 2009a).

3. Several systems of primate vocalizations display syntactic regularities, though few are understood. As a first approximation, it appears that the relevant 'languages' can be generated by finite state machines (with numerous instances of repetitions that are suggestive of 'loops'). A few rules are understood in somewhat greater detail, however. For instance, in Cambpell's monkeys a single 'boom boom' pair can appear at the beginning of  a sequence, but virtually never elsewhere – and unlike other calls it cannot be repeated (Ouattara et al., PNAS 2009b).

4. Some syntactic modifications appear to have a regular semantic effect. In particular, the 'boom boom' pair that appears at the beginning of some Campbell's monkey vocalizations seems to indicate the context is not one of predation.

5. Finally, there are intricate cases of cross-species communication in non-human primates. For instance, although Diana monkeys have very different vocalizations from Campbell's monkeys, it was shown experimentally that they understand some of their vocalizations (and vice versa). Strikingly, even though they react with alarm when some Campbell's monkey vocalizations indicative of predators are played back, this anxiety disappears when the 'boom boom' prefix is added to them.

While we do not believe that enough is known about primate vocalizations to establish what relation, if any, they bear to human language, we are convinced that primatologists have described them in such detail that they are ripe for the kind of rigorous modelizations developed in contemporary formal linguistics – hence the term 'primate linguistics'. Students will be encouraged to embark on simple formal analyses of (what is known of) the vocalizations of several non-human primates. While many extant descriptions concern monkeys, we will also discuss recent work on ape communication – including bonobo vocalizations and chimpanzee and gorilla gestures.

Preliminary Schedule [to be adapted and completed!]

Feb. 12: Klaus Zuberbühler (Neuchâtel) , ‘Meaning from strings of calls in primate communication’.

Feb. 19: Claudia Stephan, “The vocal behaviour of Diana monkeys (Cercopithecus diana diana): flexibility and sex differences”

Abstract: It has long been thought that non-human primates possess little if no control over the acoustic structure of their vocal signals. This explains restricted call repertoires in many species but it does not explain how these monkeys respond to short-term changes in the environment. In particular, vocal flexibility is supposed to be especially important during predatory events, in which the reduction of uncertainty about the eliciting event is crucial in terms of fitness consequences. In many non-human primate species, males and females vocalize together during threatening events but whether females’ and males’ vocalizations are coordinated remains unknown.

Among forest guenons, Diana monkeys (Cercopithecus diana diana) possess a remarkable sexual dimorphism in their call repertoire and call usage, which is also reflected in their social organisation. The typical group structure is one reproducing male, who utters few different low-pitched, long-distance calls only to threatening events and typically 5-11 reproductive females who vocalize in much broader contexts, namely social interaction but also to threats, e.g. predators. Both sexes utter highly context-specific alarm calls, also “functionally referential signals”, to leopards (Panthera pardus) and eagles (Stephanoaetus coronatus), as well as general alert calls.

In this talk, I will summarize playback experiments in two habitats in West Africa, Taï National Park (Ivory Coast) and Tiwai Island (Sierra Leone). I will present empirical evidence that females’ and males’ vocal systems develop more flexibly than expected, mainly as a function of ontogenetic experiences with predators- although the impact of pre-experience on both vocal systems is considerably different. During predatory events, females and males indeed coordinate their alarm-calling behaviour, showing highly complex audience effects that may hint to a sex-specific cognitive disparity.

Readings: Stephan and Zuberbühler 2008

Feb. 26: Emmanuel Chemla (LSCP) and Philippe Schlenker (IJN/NYU) on the semantics of Campbell’s monkey calls

Readings: Ouattara et al. 2009a, b

March 5:  Anne Schel,   'Primate vocal communication'

Anne will discuss recent results pertaining to colobus monkeys and chimpanzees.

 

Research on colobus monkeys:  I will discuss the work I have carried out with two species of colobus monkeys, the Guereza and King colobus, in light of the existing data on functional reference and zoo-syntax in other primate species. We conducted classic predator playback experiments in which we played back predators' vocalizations  (leopard growls or eagle shrieks) and recorded the monkeys' responses. We found that after hearing predator sounds the colobus monkeys reacted with two basic alarm call types, snorts and acoustically variable roaring phrases. Neither call type was exclusively given to one predator type but there were striking regularities in the sequence order of calls. Leopard growls usually elicited long calling bouts consisting of a snort followed by few roaring phrases whereas eagles elicited short calling bouts consisting of long sequences usually not preceded by snorts but many roaring phrases. Further work revealed that these sequences appeared meaningful to recipients, who looked up in a significantly larger proportion of trials conducted with eagle alarms compared to leopard alarms. Although this could mean that recipients use the basic composition of these sequences to base call recognition on, I will discuss another possible  way in which these monkeys may differentiate the context of calling, based on a recent study that revealed that sequence composition in the first few seconds  may be crucial for context discrimination.

Research on chimpanzee alarm calls: The degree of intentionality underlying signal production in non-human primates is another critical issue that is central to theories of how human language has evolved. To date, this has predominantly been studied in gesture use of great apes, while comparable work on great ape vocal communication is currently lacking. I will discuss the results of my recent work carried out in collaboration with Dr. Katie Slocombe, in which we investigated the intentionality of  chimpanzee alarm calls. We presented wild chimpanzees with a python model and found that the production of two types of alarm calls exhibited the same characteristics used to establish intentionality in their gestural communication.

March 12: Catherine Hobaiter (U. Neuchâtel),  Mixing Modalities: Multimodal communication in wild chimpanzees

I will describe the communicative environment of wild chimpanzees, with particular attention to the use of vocalizations and gestures in both uni-modal communication and multi-modal combinations. Chimpanzee use of gestural communication peaks in infancy and decreases with age, whereas their use of vocalizations increases with age. Multimodal combinations are relatively rare, and are used consistently across age groups. Chimpanzees employ their communication strategically, increasing their use of multimodal communication after the failure of vocal communication. The alpha male occupies a unique position within the community, and his communication is similarly distinctive: a prolific user of gestural communication, and exposed to particularly high levels of multimodal communication, as are high-rank males in general.

March 19: no seminar

March 26: Stéphanie Mercier (U. Neuchâtel): Comparative study: an approach to get a better understanding on the evolutionary origins of audience-aware communication in primates

Presentation and literature 

In primates, group size is an important factor that influences the relative brain size of a species, the most likely source of cognitive differences (Dunbar 1998). Vervet monkeys (Chlorocebus aethiops) live in multi-males multi-females groups, with group size varying from few to over 60 individuals. Thus it is really interesting to study their complex social system as it might shed lights on some of their cognitive abilities. One way of analysing the relationships of the vervets with their conspecifics is by having a special focus on their communication system. In a first step, I will introduce the social system as well as the communication system of the vervet monkeys by describing what has been done in the past decades. Although vervets are well known to warn others of the danger thanks to several alarm calls adapted to specific kind of predators (Seyfarth et al. 1980), the effects of the presence of an audience in different natural situations still need to be investigated. In a second step, I will present the plans of my PhD project which seeks to explore one key feature of human language, the ability to take others into account during acts of communication. This project is part of a comparative study that will investigate the evolutionary origins of this audience-awareness in primates by collecting extensive observational as well as experimental data on four different primate species. On one hand, chimpanzees, most closely related to humans, will provide insights into the communication abilities of our most recent common ancestor. On the other hand, baboons, mangabeys, and vervet monkeys, more distantly related old world monkeys, will help us understanding the older phylogenetic roots of advanced communication.

Supplementary session (later): Chris Templeton (St Andrews) on birdsongs

Links

Zuberbühler, Primate Communication