African grey parrot: the bioacoustics
A research about the onset modalities of the grey parrot vocal range (Psittacus erithacus), in a compared perspective.
In this project, the onset modalities of the grey parrot vocal range are studied: humans have always captured – and consequently bred – these animals for their ability in reproducing words, entire phrases and music themes. Nevertheless, the process performed by these parrots in order to listen, develop and produce phonemes understandable by human beings, has not been efficiently inspected. In fact, the learning of vocal ranges is abundantly common among the birds and well chronicled in several passerines species, a process very similar to the one performed by the parrots.
However, experimental and neuroanatomy evidences prove that the motor nuclei geared for vocal control, in singing birds and in parrots are not the same.
These differences may prove that important divergences may exist even among the singing learning processes of the majority of passerines and the ones carried out by the parrots. For singing birds, the sub-call technique seems to be the only strategy that allows it to listen to itself again and correct its range. On the other hand, parrots produce a range of semi-phonetic sounds, which, through a constant self-listening process, are “chiseled” until they reach an harmonious outline similar to their instructors (it happens quite the same for human babies in the course of their language development in early life).
The aim of our project is to identify the several phases of the process that leads a grey parrot from sound acquisition to correct phonemic performance, and, at a later stage, to the pronunciation of Italian words. For this purpose, a young example of grey parrot born and raised in captivity, is going to be trained to the functional usage of some words, carefully selected among the ones statistically representative for Italian native tongue human infants between 6 and 24 months old. The bird is going to be trained to a semantic usage of the chosen words, taking advantage of the Todt’s Model/Rival method, refined by Irene Pepperberg at a later stage.
The theory of the M/R method is to involve the animal in a sort of conversation between two trainers, a conversation based on a physical feature of a certain object, the bird’s appetite, and the related oral tag. Each correct answer is strengthened by obtaining the object (food, toys) and by praises. Each training session will be recorded, permitting bio-acoustic and phonetic analysis. The acquired material will be digitalized and collected into an appropriate database, which will allow us to monitor the vocal range development of the parrot in the course of time.