A language is defined as a system of communication used by a particular nation or people group and general communication (according to Salzmann 1998) consists of the sender, receiver, message, channel, and desired effect. Though animals are able to communicate with one another over food, danger, and other basic necessities, they remain largely unable to create prose, literature, poetry, or to discuss the hypothetical. Over the past century, studies have shown that it is possible to distinguish between animal utterances from human language. A significant study to this endeavour was Hockett’s design features of language developed in 1960.
According to Hockett, there are 16 design features of language, seven of which are unique to humans. These are:
- Vocal-auditory channel;
- Directional reception;
- Rapid fading;
- Interchangeability;
- Total feedback;
- Specialization;
- Semanticity;
- Arbitrariness;
- Discreteness;
The following were believed to be unique to humans:
- Displacement;
- Productivity;
- Traditional transmission;
- Duality of patterning;
- Prevarication;
- Reflexiveness; and
- Learnability
There are numerous research studies on primates’ ability to acquire human-like language abilities, but these have been inconclusive at best. Two female chimpanzees, Gua (Kellogg & Kellogg 1933) and Viki (Hayes 1951), were cross fostered in human families. Both studies attempted to teach the primate to produce distinct words through vocalization. While Gua did not produce any words at all, Viki only produced four words that were barely recognizable even after years of practice. These studies show that the vocal chords of primates are not developed enough to produce discrete units of sound to form different words, lacking duality of patterning.
Since the 1960’s, researchers used a new approach of teaching American Sign Language (ASL) to primates to see if they could converse with humans. Washoe (Gardner & Gardner 1969, 1975) learned 132 signs by the age of five and displayed evidence of some human-like language characteristics. She demonstrated productivity by combining signs to form new words, had some sensitivity to semantics, and taught her adopted son, Louis, signs without human intervention. Koko (Patterson 1972), a female gorilla, also showed signs of productivity. Additionally, Koko also showed some signs of displacement by asking for a kitten to play with after the one she had died.
However, the study on Nim Chimpsky (Terrace et al. 1979), a male chimpanzee, showed mixed results. After being taught ASL, the researchers wanted to find out if primates can learn syntax. He made over 2000 utterances in two years, with many of them at least two words long. But when reviewing video material of the conversations, the researchers found that 90% of the utterances were in response to trainers with rare spontaneous speech. On top of that, 40% of his signs were repetition from his trainers, casting further doubt on his ability to communicate on his own accord.
Although some studies show limited evidence that primates are capable of displacement, traditional transmission, and productivity, the overall picture remains inconclusive. Primates lack displacement, productivity, vocal-auditory channel, discreteness, duality of patterning, prevarication, and reflexiveness. These create distinct differences between animal communication and human language.
Cross-fostering studies are conducted based on ecological validity and the theory that situational factors may affect behavior (Zimbardo 1973), however, the physical constrains on a primate’s vocal chords make them unable to mimic human-like duality of patterning. Another criticism of primate research studies is based on the theory of classical conditioning, where subjects are conditioned to respond to arbitrary stimuli. The Little Albert study (Watson 1920) and salivating dogs study (Pavlov 1902) show that both animals and humans are affected by classical conditioning. This raises the concern that primates may be conditioned to respond to trainers’ ASL stimuli in to obtain a treat or verbal praise instead of initiating spontaneous communication.
Research studies on primates’ ability to learn human-like language skills are also limited in number. Each of the studies only focus on one particular primate and have different research goals with varying approach methods (e.g. teaching ASL vs. speaking words) leading to lower scientific validity. To have a comprehensive view with a persuasive conclusion, there needs to be a larger number of studies with a larger number of primates studied with the same approach. Performing research on primates are also unethical as cross-fostering removes the primate from their parents at birth and primates typically do not have the right to withdraw.
Primate research is not the only problematic issue relevant to this research topic. Certain classifications of Hockett’s design features of language are also debatable. While displacement may be unique only to humans, not all humans are capable of communicating displacement. Flynn (2013) and Luria (1932) studied how uneducated and rural people were unable to take hypothetical situations seriously. They concluded that in order to make the hypothetical possible, facts must not be concrete entities, but universals that are rendered consistent by logic. The rural Russians and uneducated Americans they studied of the early 20th century were unable to go beyond concrete world and everyday experience.
Simpson (2007) also wrote about how colonial attitudes saw external people groups that lack the capacity to reason and hypothesize as uncivilized people. If we take Hockett’s principle of displacement as being quintessential to human language, then by applying consistent logic, it classifies those people in rural Russia with less than four years of education and other people without the capacity to hypothesize as necessarily unhuman humans. This logical conclusion that some people are less human than others is incongruent with the contemporary belief that all people exist as equals.
Another problematic classification in Hockett’s theory is that learnability is a trait unique to human languages. Although there is currently no evidence to show that animals can learn the communication techniques of other animals, this does not exclude the possibility of humans learning animal communication. Oxana Malaya (1991), and Ivan Mishukov (1998), Andrei Tolstyk (2004) learned dog barking, growling, canine mannerisms after being neglected by their parents and being raised by dogs. Prava the bird boy (2008) can also only communicate by chirping and winnowing arms like wings after being trapped in an aviary for the first eight years of his life.
From inconclusive primate research evidence, human language can be distinguished from animal communication. However, primate research up to date has limited concrete evidence, debatable ethics, and Hockett’s design features of language may be in need of revision since it is a theory developed over half a century ago.
