7. References

African Grey Parrot Personality, Food & Care – Pet Birds by Lafeber Co. Retrieved March 15, 2019 from https://lafeber.com/pet-birds/species/african-grey-parrot/

Alex, B. (2018). How Did Human Language Evolve? Scientists Still Don’t Know. Retrieved from http://blogs.discovermagazine.com/crux/2018/12/07/where-does-language-come-from/#.XMVwYegzYuU

Arthur – Alex Foundation. (2013). Retrieved from https://alexfoundation.org/arthur/

Barker, T. (2017). Zebra finch study finds mixed impact of early-life stress [Blog]. Retrieved from https://blogs.illinois.edu/view/7447/516042

Berwick, R., Okanoya, K., Beckers, G., & Bolhuis, J. (2011). Songs to syntax: the linguistics of birdsong. Trends In Cognitive Sciences, 15(3), 113-121. doi: 10.1016/j.tics.2011.01.002

Buck, R., & VanLear, C. A. (2002). Verbal and nonverbal communication: Distinguishing symbolic, spontaneous, and pseudo-spontaneous nonverbal behavior. Journal of communication, 52(3), 522-541.

Carey, B. (2007). Alex, a Parrot Who Had a Way With Words, Dies. Retrieved March 15, 2019 from https://www.nytimes.com/2007/09/10/science/10cnd-parrot.html

Chapman, M., James, V., & Barrett-Lee, L. (2012). The girl with no name. Mainstream Publishing.


Chomsky, N. (1992). On the nature, use and acquisition of language. Thirty Years of Linguistic Evolution. Studies in Honor of René Dirven on the Occasion of his Sixtieth Birthday. Philadelphia: John Benjamins, 3-29.

Darwin, C. (1871). The descent of man: And selection in relation to sex. London: J. Murray.

Erard, M. & Matacic, C. (2018). Can these birds explain how language first evolved? [Online article]. Retrieved from https://www.sciencemag.org/news/2018/08/can-these-birds-explain-how-language-first-evolved

Fromkin, V., Krashen, S., Curtiss, S., Rigler, D., & Rigler, M. (1974). The development of language in Genie: A case of language acquisition beyond the “critical period”. Brain and language, 1(1), 81-107.

Gibson, K. R., & Tallerman, M. (Eds.). (2012). Oxford Handbook of Language Evolution (p. 110). Oxford University Press.

Hakuta, K., Bialystok, E., & Wiley, E. (2003). Critical Evidence. Psychological Science, 14(1), 31-38. doi: 10.1111/1467-9280.01415

Hattenstone, S. (2013). Was Marina Chapman really brought up by monkeys? The Guardian. Retrieved April 24, 2019 from  https://www.theguardian.com/science/2013/apr/13/marina-chapman-monkeys

Hauser, M. D., Chomsky, N., and Fitch, W. T. (2002). The faculty of language: What is it, who has it, and how did it evolve? Science 298, 1569–1579.

Hedeager, U. (2003). Is language unique to the human species? Retrieved April 24, 2019 from http://www.columbia.edu/~rmk7/HC/HC_Readings/AnimalComm.pdf

Herman, L. M. (1986). Cognition and language competencies of bottlenosed dolphins. Dolphin cognition and behavior: A comparative approach, 221-252.

Holman, R. (2008). Psittacus erithacus (grey parrot). Retrieved from https://animaldiversity.org/accounts/Psittacus_erithacus/

Jablonka, E., Ginsburg, S., & Dor, D. (2012). The co-evolution of language and emotions. Philosophical Transactions of the Royal Society B: Biological Sciences, 367(1599), 2152-2159.

Kent, J. 1972. Eight months in the hospital. Paper presented at the 80th Annual Convention of the American Psychological Association, Honolulu, Hawaii, Sept. l-8.

Lamoureux, A. (2018). Why Alex The Parrot May Have Been The World’s Smartest Bird [VIDEO]. Retrieved March 15, 2019 from https://allthatsinteresting.com/alex-the-parrot-irene-pepperberg

Lehrer, J. (2008). Bird Brains: Are Parrots Smarter Than a Human Two-Year-Old?. Retrieved from https://www.scientificamerican.com/article/bird-brains-parrots-smarter/

Lyons, J. (2006). Natural language and universal grammar. Cambridge: Cambridge University Press, p.1.

Mehler, J., Christophe, A., Ramus, F., Marantz, A., Miyashita, Y., & O’Neil, W. (2000). How infants acquire language: some preliminary observations. In Image, Language, Brain: Papers from the first Mind-Brain Articulation Project symposium (pp. 51-75). MIT Press, Cambridge, MA.

Okanoya, K. (2012). Behavioural factors governing song complexity in Bengalese finches. International Journal of Comparative Psychology, 25(1).

Pepperberg, I. M. (2002). Cognitive and communicative abilities of grey parrots. Current Directions in Psychological Science, 11(3), 83-87.

Pepperberg, I. (2007). Grey parrots do not always ‘parrot’: the roles of imitation and phonological awareness in the creation of new labels from existing vocalizations. Language Sciences, 29(1), 1-13. doi: 10.1016/j.langsci.2005.12.002

Pepperberg, I. (2010). Vocal learning in Grey parrots: A brief review of perception, production, and cross-species comparisons. Brain And Language, 115(1), 81-91. doi: 10.1016/j.bandl.2009.11.002

Pepperberg, I. (2012). Evolution of communication and language: insights from parrots and songbirds. In M. Tallerman & K. Gibson, The Oxford Handbook of Language Evolution (1st ed., pp. 109-119). New York: Oxford University Press Inc.

Pepperberg, I. (2017). Athena the parrot [Image]. Retrieved from https://lafeber.com/pet-birds/wp-content/uploads/PepperbergParrot.jpg

Pepperberg, I. (2017). Inside Pepperberg’s Lab: African Grey Athena’s Antics – Pet Birds by Lafeber Co. Retrieved from https://lafeber.com/pet-birds/inside-pepperbergs-lab-african-grey-athenas-antics/

Pepperberg, I. (2019). Study shows parrots can pass classic test of intelligence. Retrieved March 15, 2019 from https://phys.org/news/2019-02-parrots-classic-intelligence.html

Radford, E. (2013). Genius African Grey Parrot Has Died [Video]. Retrieved from https://www.inquisitr.com/566539/genius-african-grey-parrot-has-died-video/

Saini, A. (2015). Language and birdsong may use the same brain structures [Online article]. Retrieved from http://www.bbc.com/earth/story/20150512-birds-hold-the-key-to-language

Savage-Rumbaugh, E. S., Rumbaugh, D. M., & Boysen, S. (1980). Do Apes Use Language? One research group considers the evidence for representational ability in apes. American Scientist, 68(1), 49-61.

Slater, P. (2012). Bird song and language. In M. Tallerman & K. Gibson, The Oxford  Handbook of Language Evolution (1st ed., pp. 96-101). New York: Oxford University Press Inc.

Smith, D. (1999). A Thinking Bird or Just Another Birdbrain?. Retrieved March 15, 2019 from https://www.nytimes.com/1999/10/09/arts/a-thinking-bird-or-just-another-birdbrain.html?showabstract=1

Stout, D., & Chaminade, T. (2012). Stone tools, language and the brain in human evolution. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 367(1585), 75–87. doi:10.1098/rstb.2011.0099

Suzuki, T., Wheatcroft, D., & Griesser, M. (2016). Experimental evidence for compositional  syntax in bird calls. Nature Communications, 7(1). doi: 10.1038/ncomms10986

Thomas, J. (1995). Center-embedding and self-embedding in human language processing (Masters). Massachusetts Institute of Technology.

Thomas, J. G. (2014). Self-domestication and language evolution.

Thomas, J., & Kirby, S. (2018). Self domestication and the evolution of language. Biology & philosophy, 33(1-2), 9.

University of Lincoln. (2014, February 25). Reciprocity and parrots: Griffin the grey parrot appears to understand benefits of sharing, study suggests. ScienceDaily. Retrieved March 15, 2019 from www.sciencedaily.com/releases/2014/02/140225122322.htm

Vajda, E. J. (2003). Review of: An Introduction to Syntax.

Wood, S. (2005). What are formants?. Retrieved April 25, 2019 from https://person2.sol.lu.se/SidneyWood/praate/whatform.html

6. Conclusion

So in the end, do birds have language? Research has shown that there are similarities between songbirds and parrots communication and humans, but, they do not use it to the same capacity that humans do. And so, we can only conclude that while the communication systems of songbirds and parrots bear some features of language, language is still an exclusively human property. Still, there is no saying that given time, the communication systems of our feathered friends would not evolve to acquire even more features of language. As Charles Darwin writes in The Descent of Man (1871), “The sounds uttered by birds offer in several respects the nearest analogy to language.”

5. Human language

Language is one of human’s most important and unique defining characteristics, as no other creature in the world is able to use it (Hedeager, 2003). Language requires both verbal and non-verbal forms of communication in order for all parties to understand one another. Verbal communication involves forming words and putting them together to form sentences while non-verbal forms of communication include gestures, such as yawning to indicate fatigue, or pointing to bring attention to an object of interest (Buck & VanLear, 2002). The closest thing to a language would be the communication between animals as their own form of communication includes sounds or gestures which are also present in human language, such as the songs of songbirds. However, the sounds they make do not form cohesive words or sentences and hence cannot be considered language.

Although humans have language, it is not an innate ability. Animals will still behave and communicate the way others from their species do, even if they grew up in isolation. however, the same cannot be said for humans. If humans grow up in isolation, their form of communication would be similar to that of animals – gestures and noises. Since performing experiments which isolate children is unethical, there is not much research in that area. However, there have been documented cases of feral children in the past which help to shed some light on the consequences if such a thing were to happen. For instance, Marina Chapman, more widely known as “The Girl With No Name”, is someone who claimed to have grown up in the wilderness with monkeys and no human contact or communication for five years (Chapman et al., 2012). And when she was found in a Colombian jungle by hunters, she had lost her language completely (Hattenstone, 2013). Another more well-documented example would be Genie, a girl who experienced extreme social isolation and abuse from her father at a young age. According to Dr. James Kent (1972) who observed her, she appeared to have no language, making no sounds apart from whimpering and some gestures to express certain emotions. Scientists observed that she had little control over her laryngeal mechanisms and language comprehension tests also showed that she had almost no comprehension of grammatical structure (Fromkin et al., 1974). The feral children’s inability to produce language after being isolated prove that while language is something unique to humans, it is not innate.

As has been mentioned throughout this wiki chapter, language is considered by many to be a unique characteristic to humans and has the specific trait of hierarchical syntax and structure. With hierarchical syntax, the sentence “Kelly, who was out for brunch with Tim, was late to the meeting.” (Alex, 2018) tells readers that Kelly was the one who was late to the meeting, not Tim. Syntax is concerned with the way smaller words and phrases which can be organised as a unit, form sentences of varying structures (Vajda, 2003). In an article written by Alex (2018), she explains that hierarchical syntax is present when these units are organized in a hierarchical structure and embedded inside one another to form larger constituents. And it is this syntax which allows readers to correctly interpret that Kelly was the one late to the meeting, even though Tim is closer to the verb “late” in the sentence (Alex, 2018).

Alex (2018) explains one popular theory this in her article: language evolution happens in stages; the first of which is proto-language, a system of communication more complex than ape communication but lacking elements of modern language. This theory proposes that language developed as a result of evolutionary adaptation. But as for the proto-language itself and what it was like, Alex (2018) says that researchers are more split. Some argue that our ancestors sang before they spoke, while others claim that the proto-language used was dominated by pantomimed gestures – a society built on charades, which is similar to the way apes communicate today. This idea of language as an evolutionary adaptation is further explained in wiki chapter 2 and wiki chapter 15.

4. Self-domestication hypothesis

4.0 The Self-domestication of humans

Why did bird “language” (or, birdsongs) not evolve to the extent that human language (natural language) did? We may approach this question by examining the converse: Why did human language evolve to an extent unobserved in the communication system of birds? One hypothesis is the human self-domestication hypothesis. The basic idea of self-domestication is that among the driving forces of human evolution, humans selected their companions depending on prosociality. They preferred mates who were more intelligent, creative, and articulate; prosocial and cooperative behaviours were desirable in a mate. This selective pressure for more cooperation caused humans to evolve differently from other hominids, both behaviorally and cognitively. It is postulated that Self-domestication may have facilitated the emergence of complex behaviours via cultural evolution, in particular, of more complex languages in order to support more complex cultural practices (Thomas, 1994).

We may also think of self-domestication as follows: early humans adapted the environment for themselves (e.g. by making tools and erecting shelters), and subsequent generations gradually adapted to the increasingly man-made environment. Self-domestication (of humans) in this sense occurred through generations of changing and adapting to the environment without direct interference by other non-human species. As aforementioned, the selection of mates who had more prosocial behaviour was one of the driving forces of human evolution. This direction of human evolution–towards a species that possesses an increasingly complex language–potentially played a role in shaping the kind of physical environment that humans made for themselves. Therefore, it is important to consider the different factors that were at play in the self-domestication of humans, and view the process holistically.

4.1 Birds in the wild vs. Birds in captivity

Unlike humans, birds did not undergo the process of self-domestication, and this is one plausible reason bird songs did not evolve to possess all the criteria of a language. This hypothesis is supported by the observation that domesticated songbirds have songs that are more complex than their wild counterparts (Erard and Matacic, 2018; Thomas and Kirby, 2018). One example is the Bengalese finch (Lonchura striata domestica), a domesticated, possibly hybrid, descendent of the white-rumped munia (Lonchura striata). According to avicultural literature, white-rumped munias were imported into Japan in 1762 and domesticated due to their tameness. The domesticated variety of white-rumped munias were then referred to as Bengalese finches. This variety does not occur in the wild. The songs of white-rumped munias are observed to be less complex and melodious, as well as more repetitive than the songs of their domesticated descendents. There are two main reasons for the disparity in song complexity between the wild and domestic songbirds including the presence of (1) predators and (2) sympatric (i.e. closely-related or overlapping) species in the wild, including the spotted munia (Lonchura punctulata), a sympatric species of the white-rumped munia (Okanoya, 2015).

Firstly, for the white-rumped munia, singing in the wild is a dangerous activity that draws the attention of not only his potential mate, but also its predators. Consequently, the male munia bird spends less time singing as compared to his Bengalese finch counterpart. There is reduced cultural transmission in the wild munia, whereby the father spends less time teaching his song, and the son spends less time practising the inherited songs. Reduced singing time also means having less time to improvise and introduce variations to the song. Moreover, the learner’s songs are observed to have a higher fidelity to his tutor’s song. Secondly, the presence of sympatric species means that the white-rumped munias have to keep their songs simple to help distinguish their songs from the songs of other closely related bird species, such as the spotted munias. This reduces the likelihood of hybridisation and its associated disadvantages, such as lower fertility in the offspring (Okanoya, 2015; Thomas, 1994).

On the other hand, the domesticated Bengalese finch does not face the risk of being heard by predators in the safety of his enclosure, and is thus free to sing to his heart’s content. This leads to an increased role for cultural transmission of songs from father to son. With an increased singing time, the learner is able to further experiment with the tunes, improvise, and add variations to the songs. The absence of sympatric speciation means that their songs can be as colourful as they want it to be. The result is a lower fidelity of the learner’s song to his tutor’s song. Without constraints on their song systems, Bengalese finches were free to develop their songs to a higher level of complexity. This might have been one of the factors that led to the evolution of a larger brain interfacialis (one of the song control circuits) in the Bengalese finch to help it cope with the complexities of its song, which in turn further allowed for development of even more complex songs (Thomas, 1994). One Science article discusses the comparison between the songs of the two songbird species presented by ornithologist Kazuo Okanoya.

Munia song (K. Okanoya)

Bengalese finch song (K. Okanoya)

While domestication is evidenced to contribute to the evolution of language, or bird songs in this case, the lack of self-domestication in songbirds is a plausible reason that bird songs did not evolve to the extent that human language did.

4.2 Cooperation, tool-making, and human language evolution

As mentioned above, cooperation led to greater cognitive abilities in humans. Combined with extensive physical abilities, humans developed in the area of tool-making (Stout, 2012). This activity is believed to have facilitated the evolution of human language in more than one way. One instance might be the evolution of words as types of signals. For example, consider the word ‘snake’. For the early or pre-humans, the exclamation “snake!” was likely predominantly a danger signal. When humans later developed tools for hunting, the call ‘snake’ evolved to signal not only danger, but also the presence of a prey in one’s surroundings (i.e. food). Today, the modern man does not necessarily link the word ‘snake’ to a danger signal or food; we have become creative with the use of the word. For example, man conceived of Medusa with venomous snakes for hair, to represent a certain image of the Greek mythological monster.

In contrast, we can imagine that for birds, alarm calls that signal danger would not evolve to signal something else; the bird’s call for ‘snake’ will always only signal danger. One plausible explanation is that such calls do not evolve so as to retain its survival value. Therefore, we may think of bird calls as primarily for survival purposes (i.e. for preservation of both self and species), and perhaps secondarily for pleasure–a luxury not all birds can afford.

Then again, readers may ask: Do songbirds sing for their own pleasure? Perhaps they do, from time to time. For domesticated songbirds especially, it may start off with experimenting with different sounds, just because their environment allows for it at little to no cost (see section 4.1). Over time, these birds may improvise and develop their “own” songs. Seeing as how this is a self-motivated process not done out of necessity, it might suggest that some learners do find pleasure in singing, which in turn allows for the development of more elaborate songs under suitable environmental conditions. One possible test for this might be to monitor the neural activity of songbirds in the wild and in captivity. Specifically, a test could be designed to monitor and measure the dopamine signalling in white-rumped munias and Bengalese finches during their practice singing sessions. This test will possibly determine if there is a general discrepancy in the amount of dopamine signalling between the two groups. One difficulty of this study, however, is the necessary domestication of wild munias to some extent, which might interfere with the results of the study.

In short, we humans owe the evolution of our language to our greater physical and intellectual capabilities, which allowed for the development of human language to a degree not attained by birds.

4.3 Abstraction and Language evolution

Another theory regarding the more sophisticated development of human language versus bird songs discusses the link between evolutionary changes in the human brain and the emergence of abstract thought. It is proposed that the beginning of abstract thought and creative pursuits such as cave art, coincides with evolutionary changes in the human brain between 70,000 and 100,000 years ago (Saini, 2015). This could have potentially sparked the birth of the complex, sophisticated form of language we use today. Some linguists propose that similarities in speech-associated brain structures and genes in humans and birds contribute to the parallels in the evolution of human language and birdsongs. Others, including birdsong expert Johan Bolhuis, are however skeptical about this explanation of the origins of human language. In his book Aspects of the Theory of Syntax (1964), American intellectual Noam Chomsky proposes the theory of “universal grammar”, which posits the innateness of grammar to humans. The acquisition of grammar requires the capability to form abstract thoughts, such that illogical or nonsensical sentences can still be grammatically sound. Human language might be the only language that features grammar, and we owe this to our ability for abstract thinking.

Listed below are some distinguishing factors between birds and humans that may be worth consideration:

  1. Unlike (some) humans, birds probably do not try to develop an understanding of the world using a language other than their own; we may assume parallels between such an activity and the arbitrariness of human language. Just as how humans give meaning to arbitrary sounds, we may try to study and give meaning to another animal’s call, sometimes using clues from our environment (e.g. a skinny stray cat’s meow could mean hunger), other times attaching meaning to the sound possibly based on one’s whims (e.g. I think my cat misses me when he meows like this).
  2. Humans try to find meaning in words. For example, consider the word ‘snake’ which used to signal danger. Now, we may use it to describe a snaking road. Birds would never do this. (At least, they are not observed to do so). Therefore, as observed, birds likely do not have the capacity for abstraction and concepts.

4.4 Miscellaneous thoughts

  • Are abstract thoughts communicated only with words, or can they be present in other forms of animal communication such as birdsongs, gestures, sign language, etc.?
  • Do birds have abstract thought/understand concepts?
    • The understanding of concepts/abstract idea was observed in Alex, who could count. Did Alex go through a process of translation from his language to human language when he exhibited the ability to count (capacity for abstraction)? It would be interesting to study if they exhibited such behaviour in their own “language”.

3. Grey parrots and language

3.0 Who are they?

Widely regarded as one of the smartest species of birds around (Holman, 2008), grey parrots are well known for their imitation abilities, as well as their capacity for logic and certain abstract concepts.

With English as a medium and a surprising ability to answer questions, some grey parrots in particular can make it seem like they have the capacity for language.

3.1 The African Grey Parrot

Psittacus erithacus, more commonly known as the African grey parrot, is a species of the Psittacidae family that originates from the savannas, coastal mangroves, woodland and edges of forest clearings of Central and West Africa. There are two subspecies of African grey parrots, namely the Timneh African grey and the Congo African grey, of which the latter is more popular amongst pet owners (“African Grey Parrot Personality, Food & Care – Pet Birds by Lafeber Co.”, n.d.).

3.2 Vocalization and communication in the wild

In the wild, grey parrots communicate via a variety of different types of calls and vocalizations, including alarm calls, contact calls, food begging calls, and agonistic calls (Holman, 2008). They are also known to follow a daily pattern of vocalizations, where there are two main periods of vocalization in a day. The flock is generally quiet from sunset till dawn, until they vocalize at day break prior to dispersing to forage at various locations. Upon returning to the roosting site at dusk, there is another period of vocalization, and the cycle repeats the next day. The young learn these vocalizations from parents and flock mates, allowing for cultural transmission of vocalizations from generation to generation of grey parrots (Holman, 2008). Furthermore, to summarize a finding by Bottoni et al. (2003), African grey parrots are able to distinguish the similarities and differences in musical note frequencies and even master the musical code. This demonstrates their complex cognitive competence.

3.3 Vocalization and communication in human captivity

In human captivity, the physical capacities of African grey parrots ―namely speech perception and production― include being able to distinguish and reproduce most human tokens (vowels, consonants) accurately, as well as human-like formant structures (Gibson & Tallerman, 2012). Formants are concentrations of acoustic energy around a particular frequency in the speech wave, such that each different formant corresponds to a resonance in the vocal tract. These formants can be clearly observed as dark bands in wideband spectrograms, giving an estimate of vocal tract resonances in the case of voice (Wood, 2005). This thus means that grey parrots can replicate the resonances of human voice accurately. They are also able to repeat words and phrases after hearing them just once or twice. Unlike the habits of those in the wild as mentioned above, pet parrots will not learn appropriate vocalizations, but will show similar patterns and use of calls (Holman, 2008).

African grey parrots are also capable of imitation and referential communication, of which they are most widely known for imitation of human speech. This bird reaches full talking ability around a year of age, and most individuals become capable mimics much earlier (“African Grey Parrot Personality, Food & Care – Pet Birds by Lafeber Co.”, n.d.). They use reproduced English speech sounds to meaningfully interact with humans and to comment on items of interest in their lives (Gibson & Tallerman, 2012), and are able to learn novel vocalizations by isolating a sound from background noise, imitating it, categorizing the acoustic stimulus, encoding it into long term memory, and monitoring the output sound to match it with the internal template (Bottoni, et al., 2003). Grey parrots in captivity have also been observed to carry out untrained vocal practice and sound play (Pepperberg, 2010). In addition, it has been found that they learn socially, by observing moods in situations and emulating the noises used in such cases when a similar mood arises in the future.

3.4 Case study: Who was Alex?

Undoubtedly the most renowned of his kind, Alex was a grey parrot who lived from 1976 – 2007, and passed at the age of 31 years due to a deadly condition called atherosclerosis, or build-up of plaque in the arteries. For almost all his life, Alex was raised and trained by Dr. Irene Pepperberg, a comparative psychologist who had bought him at a pet store in 1977 back when she was a doctoral student in chemistry at Harvard. Dr. Pepperberg’s work with Alex began at a time when scientists had little expectation that any bird could learn to communicate with humans, and surpassing all expectations at the time made Alex a pioneer of his kind. Thereafter, the rest was history, and Alex spent the rest of his life participating in research at Brandeis University and Harvard University.

Figure 2. Irene Pepperberg with Alex the parrot

Figure 2. Irene Pepperberg with Alex the parrot (Lamoureux, 2018)

3.5 Alex’s abilities

In his lifetime, Alex achieved many milestones in Dr. Pepperberg’s lab. Some of Alex’s accomplishments and abilities included:

  • Possessing a vocabulary of up to 150 words (Lamoureux, 2018)
  • Privately vocally practising before acquiring targeted utterances (Pepperberg, 2010)
  • Actively matching memorized templates (phoneme combination, sound play) (Gibson & Tallerman, 2012)
  • Attempting to match a given word by pairing different templates of words from his memory. (Pepperberg, 2007)
  • While no direct evidence exists for birds, during a task, Alex seemingly manipulated the trainer into asking the question he seemingly desired to answer, perhaps suggesting some evidence for a theory of mind (Lehrer, 2008)
  • The ability to label 50 different objects, 7 colors, 5 shapes, and quantities up to and including six. He would combine these labels to identify, request, refuse, categorize, and quantify 100 different objects. Alex also had functional use of phases and had concepts of category, number, relative size, absence, and same versus different. (Holman, 2008; Pepperberg, 2007)
  • In the week before his death, Alex was working with Dr. Pepperberg on compound words and hard-to-pronounce words. (Carey, 2007)

Here is a video showcasing Alex in action, which abilities can you identify?

Video: Alex the parrot in action

3.6 The future: Griffin, Arthur, and Athena

Alex’s accomplishments have inspired further work with other African Grey parrots including Arthur, Griffin, and Athena. All three of them were and are respectively studied at Dr. Pepperberg’s lab at Harvard. Unfortunately, Arthur passed at the early age of 14 due to a suspected hereditary condition, which may have caused the little known avian disease Avian Bornavirus (ABV) that eventually led to his untimely death (Radford, 2013). This left Griffin to go on to become the eldest and most advanced in Pepperberg’s lab, where he can be said to be Alex’s successor.

Figure 3. Arthur (“Arthur – Alex Foundation”, 2013)

For example, Griffin can outperform children on certain cognitive tests. In one such cognitive test, Griffin was forced to gamble to test understanding of certainty versus mere possibility, and inference by exclusion. He succeeded where even human 5 year olds would fail (Pepperberg, 2019). Another cognitive test saw Griffin participating in a study into whether grey parrots understand the notion of sharing. Griffin consistently favoured the option of ‘sharing’ with two different human partners, suggesting that grey parrots can learn the benefits of reciprocity, and in turn exhibit some levels of reciprocity (University of Lincoln, 2014).

Figure 4. Griffin (University of Lincoln, 2014)

Since then, Athena has joined as the newest addition to the Pepperberg Lab. The first paper Athena contributed to was accepted for publication in 2017 (Pepperberg, 2017).

Figure 5. Athena (Pepperberg, 2017)

Figure 3. Griffin (University of Lincoln, 2014)

Figure 4. Arthur (“Arthur – Alex Foundation”, 2013)

Figure 5. Athena (Pepperberg, 2017)

3.7 Do grey parrots really have language?

Grey parrots can even outperform human children on more complex cognitive tasks and seemingly communicate with humans via natural language once trained. While this makes them appear to be capable of language to a certain extent, this is not actually the case due to three main factors.

The first is syntax, for which whatever syntax Alex had was simpler, very much unlike our complex forms of communication (Smith, 1999; Lamoureux, 2018). This alone makes it difficult to claim that Alex’s use and command of English was actually language.

The second factor can be chalked down to the needs and behaviour of the parrots in the wild as compared to in human captivity. With effective training methods under a controlled environment in captivity, Dr Pepperberg was able to push the boundaries with Alex. However, grey parrots will not naturally exhibit such abilities because these additional abilities are not necessary for survival in the wild. It should be noted that grey parrots already have their own forms of communication in the wild as mentioned earlier, such as specific periods of vocalization and various types of calls to serve their needs, making human language unnecessary for them. While it is possible to claim that Alex and Griffin demonstrated the capacity for a rudimentary form of language, it must be made clear that this was only once they were trained by humans. Without human contact, they would not have made such an evolutionary jump even if they possessed some semblance of capacity for it.

The last factor to consider is the methodology that Dr. Pepperberg used to train the grey parrots in her lab. Dr. Pepperberg attributes what she calls Alex’s ability to reason and process complex information to her training methods. These training methods  follow those of renowned behaviourist B. F. Skinner, meaning that responses may have been prompted by a very effective reward in the form of food (Smith, 1999). Although Dr. Pepperberg initially uses the particular training object itself as a reward so that the bird associates the word with the object (Smith, 1999), if the parrots were constantly prompted with enjoyable rewards, there would be no motivation or reason for the bird to think logically outside of the experiment. Without the logical thinking that comes with use of complex language, can parrots really be said to have the capacity for language? It is also possible that Pepperberg may have unconsciously given the subjects’ cues, which would have affected the accuracy and reliability of results.

Hence, with these three factors in mind, we can draw the conclusion that grey parrots do not actually have language.

2. Songbirds and language

There are over 5000 species of songbirds, all of which are of the suborder of Passeri. Their method of communication systems are songs and simple calls. They use calls for simple functions and more elaborate songs to find mates. In the first wiki chapter, the design features of Charles Hockett were introduced. In this section, we review two of them, cultural transmission and syntax, and investigate whether they are present in songbirds’ communication.

2.1 Cultural transmission

An important commonality between songbirds and humans involves the way they learn to communicate.

Firstly, they both exhibit sensitive periods in learning. While scientists do not agree on any concrete period, the general consensus is that it is during the first few years of our lives (Hakuta, Bialystok & Wiley, 2003). But for songbirds, it occurs during their first few months. During this critical period, the volume and connectivity of their brain cells responsible for song learning and production increases (Barker, 2017). If a songbird is not exposed to any birdsong during the critical period, it will still be able to sing, but only simple songs. Secondly, for their songs to develop well, they require an older bird to teach them to sing, similar to how infants require exposure to human vocalizations when they are young (Mehler et al., 2000).

Their song development occurs in two overlapping stages. The first stage, roughly 15 to 60 days after the birds hatch, involves learning songs from older “tutor” male songbirds. The second stage, occurring around 30 to 90 days after hatching, has the birds practicing, refining, and memorizing the song that they will sing for life (Barker, 2017).

Even though hatchlings learn their songs from older male songbirds, occasionally, a songbird may sing a note incorrectly. These variations from generation to generation lead to changes in their songs (Slater, 2012).

2.2 Syntax

There have been studies carried out which analyse bird songs. Berwick et al (2011) analysed the syntax in bird songs and compared them to human language. In the paper, the researchers claimed that songs had fixed sequences. The songs either contained only sporadic variation, or contained more variable sequences where a song element might be followed by several alternatives.

Figure 1. Spectrogram of a typical Zebra Finch song (Berwick et al., 2012)

Figure 1 shows that there is a clear hierarchical structure to their bird song. Their analysis showed that songs often started with introductory notes, as indicated by the ‘i’ in the figure before the actual song begins. The songs had distinct ‘notes’ which could be combined as particular sequences into syllables, syllables into ‘motifs’, and ‘motifs’ into ‘bouts’. There is a clear similarity to the hierarchical structure in the human language. In human language, we take individual phonemes (‘notes’), combine them into syllables (‘syllables’), and then into words (‘motifs’). Combining all the words together eventually forms a sentence (‘bouts’). Thus, it can be posited that bird songs consist of chains of discrete acoustic elements arranged in a particular temporal order. What this means is that they have a finite number of sounds which can be combined to form endless different meanings, a feature of human language known as productivity. Therefore, if birds have this ability it must mean they have language too.

Their capacity for productivity was demonstrated in a study by Suzuki et al. (2016) which looked to analyse the syntax of the calls of the parus minor. In one of their experiments, they played recordings of one their calls in two different orders: ABC-D (natural sequence) and D-ABC (artificially reversed sequence). The ‘D’ part of the call is used by the caller to gather the other birds to them. When the first call was played, the birds would fly close to the speaker which played the sound. On the other hand, when the artificially reversed sequence was played, the birds only responded occasionally. This experiment is evidence that birds may have a compositional syntax.

However, while the experiment was able to provide evidence for syntactic structure in parus minor bird songs, it is inaccurate to say that it is comparable to human language because they lack one fundamental aspect: semantics.

Songbirds are only able to convey limited intentions (Berwick et al., 2011). For example, if there was a predator approaching them, they would not be able to describe what the danger is, like what type of animal it is or how many there were. They would only be able to convey notions of flying or danger.

Thus, Berwick et al (2011) concluded that they do not have grammatical syntax but only phonological syntax. This means that there are only a certain set of units that can be arranged in particular ways, and these arrangements may not necessarily create new meanings.

Another reason bird communication cannot be considered language is that their system is not unbounded in length and structure.

In human language, sentences can be embedded within other sentences and recombined endlessly to form longer and longer sentences. Take for example the sentence “the hunch that the serial killer who the waitress had trusted might hide the body frightened the FBI agent into action” (Thomas, 1995), there are three clauses: “who the waitress had trusted” which is embedded in the clause “that the serial killer might hide the body” which is then embedded in the main clause “the hunch frightened the FBI agent into action”. This exhibits the open-ended novelty that Wilhelm von Humboldt famously called the “infinite use of finite means”(Chomsky, 1992), and a cornerstone in what human languages were.

Birds on the other hand have a limited ability to construct phrases. They are mostly limited to an AnBn phrase structure (Hauser et al., 2002). Thus, although songbird songs share some similarities with human language, they are not advanced enough to be considered language as they also lack other key design features of human language.

Chapter 19 – Bird(songs) and Language

2019: Lynne Lee, Amanda Lim Li Ann, Chen Yi, Trudy Loo Soo May

1. Introduction

Language is the tool of communication that sets humans apart from animals. But what if animals could learn languages too?

Natural language is a language that develops naturally between humans through interaction (Lyons, 2006). Whether animals have the capacity for language or something comparable to natural language is widely speculated, with people citing evidence from animal communication in primates (Savage-Rumbaugh et al., 1980), birds (Pepperberg, 2002) and dolphins (Herman, 1986). Language experiments conducted on primates have also been carried out over the years with varying degrees of success – Koko the Gorilla, Washoe and Kanzi, just to name a few. These animals have shown that they are able to learn and use aspects of human languages to a certain extent. More recent language experiments have been conducted on birds to find out whether they have language and whether some of them might even be able to learn and communicate to the extent that humans do. This wiki chapter will look at several studies of communication among songbirds and grey parrots, and discuss whether it is appropriate to claim if their communication systems are developed to a degree similar to that of human languages.