If they can, what differentiates human language from non-human animal language systems?
Some of us are lucky enough to have an animal friend to spend our newfound governmentally-mandated extra time spent at home. It could be the now twenty five weeks of almost isolation, but I swear I heard my dog talk the other day. Ok, it was probably the isolation, but it did prompt me into looking into the various linguistic abilities, both innate and learned, present within the animal kingdom.
Language is fundamental for both human and animal life, but there is variance in the usage and application. It is important to qualify the definition of language to human usage in order to compare how animals and humans acquire similar language forms. Human language consists of important differentiators including the use of opinions and syntax.
Language development in chimpanzees and apes has been a large area of research most likely due to their genetic similarities to humans. There are a few famous studies. Wahsoe leaned 250 ASL signs and formed rough sentences (Perry). Similarly, Nim Chimpsky learned about half as many signs (Marsh). Koko, however, was able to learn about 1,000 ASL signs but understood double that amount (Cohn). This would place her at a three year old vocabulary level if she was a human. Though all of these feats are impressive, they all have a striking commonality — all of these primates were using signs to get rewards. Even the trainers of Nim concluded that he did not learn language, but simply imitated them to receive prizes (Marsh).
A major difference in human and animal language learning experiments results from the use of rewards. Animals, unlike humans, are motivated only by rewards while humans seem to have a natural curiosity and inclination to participate. Given what we know about how animals act out of instinct to obtain food, it is no surprise animals are able to learn some language in order to get food. This can be compared to natural obstacles animals must learn to get their food.
Looking further, however, uncovers fascinating examples of how primates are able to use language in creative ways not otherwise thought possible. Koko created a novel sign for the word “barrette.” She also created a sign indicating she wanted her trainers to “take off” their coats (Cohn). This suggests some form of innate ability to gesture and communicate. This is similar to when children are able to distinguish phonotactic differences in words even before they learn any words or even babble (Griffiths). This might suggest that babies are born with some innate level of language.
Though babies are born with some clear ability to communicate, the way they acquire language is vastly different from the evidence seen in primates. Primates, like many other animals, are born with the ability to produce the noises and specific calls to communicate, while the vocabulary used by humans is completely learned (Hurford). Although primates like Koko, Nim, and Washoe are able to learn small amounts of signs, it is nowhere near the amount of human children in similar time periods. This is likely due to simple mimicry and rote learning rather than the formal acquisition of language done by humans. Although it is easy to say that primates like Washoe behave similarly to a two-year old child, we also have the advantage of hindsight to know that the child will develop language and syntax quickly and far surpass the ability to these animals.
There are, however, examples of animals using language with human-like qualities. Koko and Washoe were able to use language that was arbitrary and productive. Washoe created combinations for words like “metal cup drink” for thermos (Perry). Koko was also able to do this novel recombination of symbols (Cohn). This idea of language generation is still not fully met. The subject animals never generated sentences to the full ability of humans and had many syntactical errors.
Like humans, sparrow songs are learned within a critical period and these songs seem to be innately guided. They are only learned if they are exposed to them. If sparrows are only exposed to other species’ songs, they follow a species-specific structure (Marler). Unlike humans, these songs have fixed meanings and thus are not generative. This seems to follow the pattern that animals have similar characteristics as humans to an extend, but have a definite difference in language acquisition.
Man’s Best Friend
Chaser the dog is a good example of how animals are able to learn stimulus and their meanings. Not only was he able to remember each name, phonetic sound, of his toys but also, by process of elimination, make choices about unknown names. This is like child language, except that children do this naturally, on their own, without the promise of a treat. Chaser learned 1,000 words, likely due to a conditioning to discriminate between phoneme sounds. Surprisingly Chaser the dog was able to chose the toy with an unknown name provided he knew the rest. This is very similar to when children are tested for a mutual exclusivity bias. Given a banana and an unknown object, the children can deduce the name of the unknown object a vast majority of the time (JoVE). The main difference stems from the fact that Chaser needed encouragement to fetch the unknown object and did not learn from a process of deduction (Philley and Reid). Chaser may be able to do this by scent, sight recognition, and other familiarity cues to figure out the unknown rather than going through all of the known objects and deducing the unknown which is most likely the process used by humans doing a similar task. However, like the primates, Chaser’s vocabulary plateaued at a juvenile level.
Another major difference between human and animal acquisition is the ability to creatively produce new ideas. A child can hear boy and boys and girl and girls and then produce cups from cup. Alex the parrot, like the other animals explained, do not have this ability to creatively generate these ideas from other experience. Only once they have learned cups could they mimic it correctly. An interesting experiment was done where children were given a non-word like wug and they were able to produce the plural form wugs (Menn). This ability to make inferences and creatively inflect novel words seems to be unique to humans.
Despite the previous comparisons regarding animal and human experiments regarding language acquisition, there are distinct differences that must be noted. For instance, the experiments regarding primates. Though successful to an extent, the experiments lacked certain integrity — specifically that none of the trainers were native ASL speakers. They tried to incorporate the primates into their family life, but their families were not deaf and did not all use ASL to a natural fluent extent. The results could have been much different if this was not the case. This prohibits direct comparisons between animal language acquisition and human language accusation, where babies are fully immersed in a home where everyone speaks 24/7 in the language they are trying to learn.
Taking that into consideration, animal communication seems to be limited to small vocabularies and have almost no evidence of grammar or syntax. This is likely partly due to the fact that they were not properly immersed in the appropriate atmosphere, but mostly due to a biological difference in the way animals and humans are able to acquire and use language. Although some evidence of productive phrases, the language is by no means as generative as human language.
Another interesting difference is that animals have never expressed opinion, which seems to be a defining characteristic of human language. Even though some primates were able to perform many once-thought human-specific features of language like displacement, arbitrariness, productivity, and the duality of pattern, these animals never expressed opinion. These differences are not due to a lack of intelligence or lack of interest in communication, but rather these non-human animals are biologically inhibited without the adequate mental faculties for language. Without syntax, animals are only able to get so far in their communication and seems to be produced by memorization rather than novel production. This suggests something quite important and possibly controversial — that syntax is a completely separate, yet integral part of language processing and production.
Cohn, Ronald. “Why Koko the Gorilla Mattered.” Why Koko the Gorilla, Who Mastered Sign Language, Mattered, 21 June 2018, www.nationalgeographic.com/news/2018/06/gorillas-koko-sign-language-culture-animals/.
Griffiths, Sarah. “Language Is a ‘Biological Instinct’: Babies Don’t Learn to Develop Speech — They’re BORN with the Ability.” DailyMail, 9 Apr. 2014,www.dailymail.co.uk/sciencetech/article-2600623/Language- biological-instinct-Babies-dont-learn-develop-speech-theyre-BORN-ability.html.
Hurford, James R. “Human Uniqueness, Learned Symbols and Recursive Thought,”European Review 12, no. 4 (2004): 551–65.
JoVE Science Education Database. Developmental Psychology. Mutual Exclusivity: How Children Learn the Meanings of Words. JoVE, Cambridge, MA, (2018).
Marler, P. and Peters, S. (1987), A Sensitive Period for Song Acquisition in the Song Sparrow, Melospiza melodia: A Case of Age‐limited Learning. Ethology, 76: 89–100. doi:10.1111/j.1439–0310.1987.tb00675.x
Marsh, James. “‘Project Nim’: A Chimp’s Very Human, Very Sad Life.” NPR, NPR, 20 July 2011, www.npr.org/2011/07/20/138467156/project-nim-a-chimps-very-human-very-sad-life.
Menn, Lise, and Nina Dronkers. Psycholinguistics: Introduction and Applications. Plural Publishing, Inc., 2017.
Perry, Nick. “‘Signing’ Chimp Washoe Broke Language Barrier.” The Seattle Times, The Seattle Times Company, 1 Nov. 2007, www.seattletimes.com/seattle-news/signing-chimp-washoe-broke-language-barrier/.
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