Anonim

In the 2.0 era when we talk about tweeting (tweets, in English), our thoughts immediately travel to Twitter and ultra-fast communication in 140 characters. But between the melodic singing of birds and the human voices there would exist a correlation that goes beyond the Internet and social networks. There is some evidence that would show that men and birds have in common genes and brain structures associated with the use of the word. For this reason, some scientists believe that the study of birds can clarify how human language has evolved, as explained by Angela Saini in a documentary on BBC Radio 4.

Word of Darwin (and not only). In his masterpiece The Origin of Species, a milestone in modern biology, the naturalist Charles Darwin writes: «The sounds emitted by birds offer, for many aspects, the closest analogy to language, because all individuals of the same species emit cries instinctive expressing their emotions; and all the species that sing exercise their faculty instinctively ".

In 2013, the linguist Shigeru Miyagawa of MIT reinforces in Darwin's concept expressed almost 155 years ago, formulating a theory according to which human language would develop from the song of birds. Together with some colleagues, Miyagawa suggests that our language is based on two distinct components, both present in simple form in less evolved animals.

Lexicon and expression. The first system is the "lexical" one (Type L), which concerns the content of the individual sentences. In man it translates into the use of words, but it is observable, for example, even in primates. The second component, defined as "expressive" (Type E), translates into the ability to structure a speech by giving it a function, similar to how birds use a certain song to mark the territory or to attract a partner.

Image A common nightingale (Luscinia megarhynchos). His singing is considered to be among the most melodious and most complex of the entire songbird scene. | Andy Sands / Nature Picture Library / contrast

Feel who sings. In his document, Miyagawa brings some examples to illustrate the Type E. The specimens of mandarin diamond (also known as diamantino) learn the songs that will chirp for the rest of life in youth, directly from their fathers. The songs do not contain "words": they are just melodies with a certain rhythm.

Even the birds renowned for their musicality, explains Miyagawa, are not able to express concepts of complete meaning. The singing baggage of a nightingale can count up to 200 songs «however the purpose of these sounds remains rather limited, usually reducing to the coupling or the delimitation of the territory. No song has a special meaning ».

Two in one. "The supplementary hypothesis" of Miyagawa suggests that man represents the only case in nature in which the lexical system and the expressive one work hand in hand: the first juggles between about 60 thousand words, the second allows to assemble them into functional schemes . The MIT linguist theorizes that our ancestors first developed the ability to "sing" birds in a similar way, and then learned to include words in their vocalizations.

Birdman. However, most linguists are not of the same idea and argue that primitive man would first develop an elementary lexical lexical system, which emit isolated lines to indicate the presence of a snake or a leopard, and then progressively learned to combine two or more words to elaborate more complex periods, up to the verbose statements we build today.

For Miyagawa this idea of ​​"protolanguage" implies an evolutionary leap too great: to create a sentence, in fact, it is not enough to put one word in another row, since the meaning of each term changes according to the context in which we insert it. The integrative hypothesis, which starts from the song of birds, would contribute to filling this inexplicable gap by introducing the expressive state.

Image A specimen of mandarin diamond (Taeniopygia guttata). | Andrew Walmsley / Nature Picture Library / contrast

So far, so close. Men and birds are quite distant within the evolutionary tree: the common ancestor dates back to about 250 million years ago, even before the dinosaurs dominated the Earth. Added to this is the fact that Miyagawa's thinking has not yet been substantiated by substantial scientific evidence. That is why, when linguists try to understand the origins of human language, they turn their eyes to our closest relatives, or primates.

However, the analogies are not lacking. The most obvious, also reported by Darwin, concerns the ability of young birds to develop their own singing repertoire by imitating adult specimens. In The Origin of the Species, reporting the thought of another naturalist, Daines Barrington, he writes that the first attempts to sing "can be compared to the imperfect effort of stuttering a child".

Furthermore, a 2009 research shows that some birds can learn the references of other species, becoming in practice "bilingual" or even "trilingual".

The talking gene. The integrative thesis could find a valuable ally in genetics. The FOXP2 gene, discovered in 2001, is called the "language gene", since its mutation can lead, among other things, to verbal disorders. A 2014 research has shown that, in addition to it, men and birds share about fifty language-related and vocal learning genes.

Simon Fisher, current director of the Max Planck Institute of Psycholinguistics in Nijmegen, the Netherlands, contributed to the identification of FOXP2. At the BBC it says that this genetic kinship is not enough to explain Miyagawa's hypothesis. The gene is in fact present in many other animals, because it is also connected to the motor sphere. The fact that in man is also associated with vocal processes depends on an evolutionary change on which it is difficult to make conjectures, but which does not, in his opinion, concern all species.

Not just words. Celebrated linguists like Noam Chomsky believe that the definition of language goes far beyond spoken language, as can be seen, for example, from the development of sign language. Chomsky, in particular, argues that the distinctive trait of human language is identified with grammar, which is universal in that even very young children instinctively grasp the rules despite not grasping the meaning of each word.

According to the most reliable theories, the key turning point in the human brain occurred between 70 thousand and 100 thousand years ago, paving the way for the evolution of language as we know it today. The period coincides with the birth of abstract thought, as well as the flourishing of rock art and jewelery production, all processes of a strictly human nature.

Image A common chimpanzee (Pan troglodytes). Despite being our closest relatives, the monkeys show many difficulties in the processes of vocal learning. Many more than some species of birds. | Cyril Ruoso / Minden Pictures / contrast

Better than monkeys. The factors that blow against the integrative hypothesis suggest that the analogies between men and birds are due to a random evolutionary convergence and that that of Miyagawa is perhaps destined to remain only a very suggestive theory. However, this does not prevent scientists from being stunned by the amazing abilities of some bird species. A 2014 study showed that the Mandarin diamond is able to discriminate the changes in intonation of the human voice, thus revealing abilities superior to many primates closely related to us. "For men, intonation is very important and can change the meaning of a sentence, " says study co-author Michelle Spierings, "We never expected birds to be so sensitive to tiny changes in our voice ».