How do animal communication systems differ from human language? Can primates acquire language?
Animals can communicate in various ways, using both verbal and non-verbal forms of communication. However, whether animals can communicate using a form of language is something which can be debated. In order to decide whether an animal has language abilities, the actual definition of language must first be considered.
"A language is a set of arbitrary vocal symbols by means of which a social group communicates." Bloch and Trager (1942)
This kind of definition would seem to apply to methods of communication in both humans and animals as regardless of the form the language may take, vocal symbols are used by animals in order to communicate with another member of their species, much like humans. However, there are features of human language which must be satisfied before a type of animal communication can be deemed to be similar to human language. There are five main properties of language, language is creative, highly structured , meaningful, referential and communicative. Can an animals communication system satisfy these characteristics?
Take, for example the vervet monkey. This is an animal which has what can be deemed to be a communication system which displays the characteristics of language. Struhsaker (1967) observed that the monkeys had developed several alarm calls, which can be used to signal to other monkeys that there is a particular type of predator looming. The monkeys essentially use a language code to warn other monkeys of the type of predator that may be approaching. Struhsaker categorised the different alarm calls that make up the vervet monkeys alarm call system. For instance, the ‘chutter’ sound warns of the presence of a cobra or puff adder, whereas the ‘rraup’ warns of an eagle nearby. Whether or not this kind of communication could be defined as a language depends on how it can satisfy the five known characteristics of language.
The vervet monkey conveys meaning in the use of each call to convey to other monkeys that there is a specific predator nearby. Therefore the language is meaningful. Furthermore, the language is referential in that it refers to an event or object in the world. But most importantly, the system is communicative in that it is an interpersonal form of communication directed at other animals. However, one of the most important aspects of human language is the use of structure and creativity in order to communicate in an associative way that allows an individual to understand words and sentence structures that may be new to us. The vervet monkey does not display creativity in it’s communication as there is no evidence of each call being incorporated into sentences or words being associated with one another to create similar or new meaning. Similarly, there is no grammatical structure to the vervet monkey’s communication, with each word being singular and having no evident prescriptive or descriptive rules governing the language and how it is spoken. Although there have been no concrete examples of animals using grammatical structure in language, it is believed that in line with present research, animals do not use structure-dependant operations when communicating.
As with grammatical structure in language, the ability to use communication to refer to things in the past or a situation or object which is not available at the time, is an ability which seems to be present in human language but not in animals. As communication in animals is usually only utilised in two areas, survival (i.e.food etc) and danger, it would seem logical that animals have no need for this type of communication. This design feature of language is referred to as displacement and refers to the ability to be able to convey things that have happened in the past to others e.g. "yesterday I visited a lovely restaurant". There is no specific need for an animal to be able to communicate in this manner in terms of prolonging survival and preventing danger. However, there is a form of displacement found in bees in their ‘waggle dance’ Bees perform a ‘round dance’ or a ‘waggle dance’ to convey to other bees the location of nectar. The bee is therefore able to communicate about an object (the flower) that is not present at the time, a feature of displacement.
As in human language, forms of communication by animals can be species-specific, much like the culturally-specific forms of human language. Most notably, birdsong is a form of communication that is not only species-specific but in some species is a learned form of communication, not innate. A human infant reared on their own will not acquire language, whereas in the animal world the role of genetics and the development of communication is more pronounced with animal communication being more of an innate feature. However, the skylark’ song is entirely learned, and the song of the chaffinch is partly modified and changed through learning (Thorpe, 1961, 1963). The bird is the exception to the innate features of language evident in other animals, a bird reared on it’s own can sing but it’s song is deemed to be abnormal and a poor form of communication for other birds. Thus, in this characteristic it would seem that birds are able to learn their form of communication through experience, much like the way the human language is developed by an infant. Although, the actual difference between birdsong and human language is quite large, with human language being developed into a more complex and structured form of language
It is clear that animal communication systems do not occupy some of the important design features of language which human communication shows evidence of. But, if animals do not entirely communicate like humans in terms of design features of the human language can they be taught to acquire it? Research into the acquisition of language by animals has mainly focused on apes and has been conducted over the last fifty years or so. In teaching apes to communicate, researchers focus on using sign language as a form of language due to the fact that apes are in actual fact physiologically unable to create human sounds. Two of the more successful attempts to teach chimps sign language occurred with two apes by the name of Washoe and Sarah. Washoe was acquired by Professor and Mrs Gardner in 1966 and was taught American sign language since she was approximately one year old. This form of sign language meant that Washoe was able to sign for specific words by performing a certain action e.g. putting her finger on top of her tongue to signify ‘sweet’. Washoe was constantly surrounded by humans who communicated to her through sign language only, thus Washoe developed her skills quite naturally with no formal training. In her acquisition of language, Washoe developed language skills that have not been widely seen in animal communication systems thus far.
One of the main skills which Washoe developed was her ability to apply meaning to an object or place by using a word to represent it. Although this kind of ability was present in the vervet monkey’s alarm call system, the purpose of the action was quite different in both cases. The vervet monkey’s applied meaning to a predator and had a call to indicate it’s presence to warn others of danger. Washoe, however was able to applying meaning to an object by signing it’s name even if the object posed no threat and had no real significance. For example, Washoe was able to recognise a flower and sign the action to signify it when she saw one. This kind of language ability shows evidence of speaking freely, a characteristic of human language. Spontaneous use of language is something which humans initiate in social situations and is not a recognised characteristic of animal communication. Animals are more likely to communicate when they need to convey something to another animal e.g. that they have found something (like a bees ‘waggle dance’), that they are being threatened (the vervet monkeys alarm call) or to protect territory or find a mate (birdsong). Therefore, the ability of Washoe to spontaneously refer to an object shows that she is able to speak freely and not just when she needs to convey information to another animal/person.
Washoe could also refer to items which may differ slightly by using the same word e.g. a key will be the same as a bunch of keys. This shows Washoe was able to extend her ability to generalise and be more associative in her language, a characteristics of human language development in infants. Possibly one of the most interesting aspects of Washoe’s language ability was her ability to creatively create two to three word sentences to convey what she wanted. Washoe’s ability to create basic sentences such as ‘ more tickle’ or ‘open food drink’ (open the fridge) shows creativity that is not entirely evident in animal communication systems. Her grasp of sign language allowed her to be able to communicate with researchers, however as expected Washoe has limited grammatical structure to her language. Unlike a human infants developed ability to understand sentence structure and basic grammar, Washoe’s sentences had no apparent constant structure and instead seemed to be given in no apparent order. This could be due to Washoe signing words instead of speaking them, it could be easier to maintain a constant structure if Washoe was able to communicate vocally.
A lack of structure in language seems evident in most forms of animal communication, even if the animal is trying to communicate using human language skills with grammatical rules and structure. Sarah, a chimp at the Univeristy of California was taught more rigidly than Washoe with training schedules and lessons involving manipulating plastic tokens that represent a word. Sarah’s sign language showed evidence of meaning in her ability to recognise words and use them as well as showing that she had developed awareness of logical notions such as ‘if’ or ‘when’. Sarah was often presented with such sentences that used logical notions, for example Sarah was presented with an apple and a banana and asked to choose one, then she was told ‘if apple, then chocolate’, Sarah then was able to understand and choose the apple to get chocolate. However, whether this understanding of logical process indicates that Sarah had learned language is not clear. Sarah’s learning was more based on associations and conditioning techniques than an actual independent grasp of language. Sarah’s grasp of word order came from the fact that if she said the correct word order she got a chocolate, if she didn’t she would get anything. Therefore, if Sarah wasn’t getting a treat every time she said something right, would she say it right at all?
Washoe and Sarah are both examples of primates who have learned to have grasp on human language techniques using sign language. Both Sarah and Washoe showed evidence of meaning, reference and attempts to be communicative in their attempts at human language. However, as with animal communication systems both Washoe and Sarah were unable to apply structure and be sufficiently creative with their language abilities, a major characteristic of human language that seems to be lacking in animals. Possibly the main differnce between human and animal communication systems is the reason behind the need to communicate. Animals need to communicate more as a necessity to survive than a social need to be able to communicate with a group. Animal communication is more based on the need to warn of danger or to describe the location of food, it is more of a necessary means of survival. Human language however adopts these characteristics of needing communication for survival but adds to them to form a language system that is both needed for survival but is also a social communication device, that is used spontaneously, something an animal does not especially require in order to survive in the animal world.
Fromkin, V. Rodman, R. (1998) An Introduction to Language. Sixth edition. London: Harcourt Brace.
Aitchison, J. (1998) The Articulate Mammal. Third edition. London:Routledge
Gleitman, H., Fridlund, Alan J. and Reisberg, D. (1999) Psychology. Fifth edition. London: W.W.Norton & Co.