mardi 10 avril 2012

PhD: Experimental evidence of a proto-language in two african nonhuman primate species

UMR 6552 Ethologie animale et humaine

Cotutelle : Alban Lemasson (UR1) / Klaus Zuberbühler (St Andrews university, UK)

Contact :

This PhD will take part to the current debate about the phylogenetic origin of human language and about the animal-human continuity. The student will be involved in a long-term interdisciplinary and international collaboration program (Pyschology – St Andrews, Ethology – Rennes) with a logistic support of ERC, ANR and IUF. Two opposed theories defending a vocal vs a gestural origin of language can be found in the international literature. Our previous studies demonstrated in the vocal communication of forest guenons some characteristics which form the core of language, such as syntax, conversation and vocal convergence. This suggests that we can find precursors of language deep inside the primate lineage. Nevertheless, these studies rely only on the ethological observation of the spontaneous behaviours of animals and we now need experimental demonstrations of the underlying cognitive processes.

The study will consist in a comparative analysis of the communicative abilities of two African guenons, Campbell’s monkeys (Cercopithecus campbelli) and Diana monkeys (Cercopithecus diana) which form polyspecific associations living on the same territory. Experiments will be settled in the field to test the ability of monkeys to:
- use a non-random call combination system to encode different messages about the environment (e.g. tree fall, eagle-leopard attack, presence of a neighbouring group). Hence, we will study here alarm c alls.
- modify the acoustic structure of their call according to the social context, in order notably to produce an acoustic structure converging to the one used by its interlocutor. Hence, we will study here contact calls.
- decode the acoustic messages at the intra and inter-specific levels.

The student will have to stay several months in the field (Taï National Parc, Ivory coast), where several free-ranging habituated groups are observable. The joint PhD will be cosupervised by Pr Klaus Zuberbühler, director of the “Taï Monkey Project” field station. The student will have access to a field station entirely equipped (car, housing, logistic) and to ivorian highly qualified field assistants. The proto-syntactic ability will be tested by broadcasting natural vs modified (artificially in the lab) male vocal sequences and by measuring the vocal and non-vocal responses of the entire group. Modifications will consist in adding/removing sound units within a call or by rearranging the call order within a vocal sequence. Experiments will involve conspecific and heterospecific subjects. The ability to vocally converge will be tested by broadcasting contact calls with different acoustic structures and by recording the vocal response by friend and non-friend females.

We will use different experimental paradigms: stimulus simple presentation, habituation-dishabituation. Sound stimuli will be broadcast using loud speakers. Several loudspeakers will be placed up in the trees to simulate the presence of an arboreal monkey. We will play sounds from the most appropriate loudspeaker according to the spatial positioning of the group members.

The candidate must have an academic training in ethology. Skills in bioacoustic are encouraged and a experience in the field is welcome.