Animal language

Animal languages are forms of communication between animals that show similarities to human language. Animals communicate through a variety of signs, such as sounds and movements. Signing among animals may be considered a form of language if the inventory of signs is large enough, the signs are relatively arbitrary, and the animals seem to produce them with a degree of volition (as opposed to relatively automatic conditioned behaviors or unconditioned instincts, usually including facial expressions).
Many researchers argue that animal communication lacks a key aspect of human language, the creation of new patterns of signs under varied circumstances. Humans, by contrast, routinely produce entirely new combinations of words. Some researchers, including the linguist Charles Hockett, argue that human language and animal communication differ so much that the underlying principles are unrelated. Accordingly, linguist Thomas A. Sebeok has proposed to not use the term "language" for animal sign systems. However, other linguists and biologists, including Marc Hauser, Noam Chomsky, and W. Tecumseh Fitch, assert that an evolutionary continuum exists between the communication methods of animal and human language.
Some experts argue the following properties separate human language from animal communication:
Research with apes, like that of Francine Patterson with Koko (gorilla) or Allen and Beatrix Gardner with Washoe (chimpanzee), suggested that apes are capable of using language that meets some of these requirements, including arbitrariness, discreteness, and productivity.
In the wild, chimpanzees have been seen "talking" to each other when warning about approaching danger. For example, if one chimpanzee sees a snake, said chimpanzee may make a low, rumbling noise, signaling for all the other chimps to climb into nearby trees. In this case, the chimpanzees' communication does not indicate displacement, as it is entirely contained to an observable event.
Arbitrariness has been noted in meerkat calls; bee dances demonstrate elements of spatial displacement; and cultural transmission has possibly occurred through language between the bonobos named Kanzi and Panbanisha.
Claims that animals have language skills akin to humans, however, are extremely controversial. In his book The Language Instinct, Steven Pinker illustrates that claims of chimpanzees acquiring language are exaggerated and rest on very limited or specious evidence.
The American linguist Charles Hockett theorized that there are sixteen features of human language that distinguish human communication from that of animals. He called these the design features of language. The features mentioned below have so far been found in all spoken human languages, and at least one is missing from any other animal communication system.
Humans are able to distinguish real words from fake words based on the phonological order of the word itself. In a 2013 study, baboons were shown to have this skill as well. The discovery has led researchers to believe that reading is not as advanced a skill as previously believed, but instead based on the ability to recognize and distinguish letters from one another. The experimental setup consisted of six young adult baboons, and results were measured by allowing the animals to use a touch screen and select whether or not the displayed word was a real word, or a non-word such as "dran" or "telk". The study lasted for six weeks, with approximately 50,000 tests completed in that time. The researchers minimized common bigrams, or combinations of two letters, in non-words, and maximized them in real words. Further studies will attempt to teach baboons how to use an artificial alphabet.
In a 2016 study, a team of biologists from several universities concluded that macaques possess vocal tracts physically capable of speech, "but lack a speech-ready brain to control it".
Among the most studied examples of non-primate languages are:
The effects of learning on auditory signaling in these animals is of interest to researchers. Several investigators have pointed out that some marine mammals appear to have the capacity to alter both the contextual and structural features of their vocalizations as a result of experience. Janik and Slater have stated that learning can modify vocalizations in one of two ways, by influencing the context in which a particular call is used, or by altering the acoustic structure of the call itself. Male California sea lions can learn to inhibit their barking in the presence of any male dominant to them, but vocalize normally when dominant males are absent. The different call types of gray seals can be selectively conditioned and controlled by different cues, and the use of food reinforcement can also modify vocal emissions. A captive male harbor seal named Hoover demonstrated a case of vocal mimicry, but similar observations have not been reported since. Still shows that under the right circumstances pinnipeds may use auditory experience in addition to environmental consequences such as food reinforcement and social feedback to modify their vocal emissions.
In a 1992 study, Robert Gisiner and Schusterman conducted experiments in which they attempted to teach syntax to a female California sea lion named Rocky. Rocky was taught signed words, then she was asked to perform various tasks dependent on word order after viewing a signed instruction. It was found that Rocky was able to determine relations between signs and words, and form basic syntax. A 1993 study by Schusterman and David Kastak found that the California sea lion was capable of understanding abstract concepts such as symmetry, sameness and transitivity. This suggests that equivalence relations can form without language.
The distinctive sounds of sea lions are produced both above and below water. To mark territory, sea lions "bark", with non-alpha males making more noise than alphas. Although females also bark, they do so less frequently and most often in connection with birthing pups or caring for their young. Females produce a highly directional bawling vocalization, the pup attraction call, which helps mothers and pups locate one another. As noted in Animal Behavior, their amphibious lifestyle has made them need acoustic communication for social organization while on land.
Sea lions can hear frequencies between 100 Hz and 40,000 Hz, and vocalize from 100 to 10,000 Hz.
It is worth distinguishing "animal language" from "animal communication", although there is some comparative interchange in certain cases (e.g. Cheney & Seyfarth's vervet monkey call studies). Animal language typically does not include bee dancing, bird song, whale song, dolphin signature whistles, prairie dog alarm calls, or the communicative systems found in most social mammals. The features of language as listed above are a dated formulation by Hockett in 1960. Through this formulation Hockett made one of the earliest attempts to break down features of human language for the purpose of applying Darwinian gradualism. Although an influence on early animal language efforts (see below), it is no longer considered the key architecture at the core of animal language research.
Animal language results are controversial for several reasons (for a related controversy, see also Clever Hans). Early chimpanzee work was executed using chimpanzee infants raised as if they were human; a test of the nature vs. nurture hypothesis. Chimpanzees have a laryngeal structure very different from that of humans, and it has been suggested that chimpanzees are not capable of voluntary control of their breathing, although better studies are needed to accurately confirm this. This combination is thought to make it very difficult for the chimpanzees to reproduce the vocal intonations required for human language. Researchers eventually moved towards a gestural (sign language) modality, as well as keyboard devices with buttons with symbols (known as "lexigrams") that the animals could press to produce artificial language. Other chimpanzees learned by observing human subjects performing the task. This latter group of researchers studying chimpanzee communication through symbol recognition (keyboard) as well as through the use of sign language (gestural), are on the forefront of communicative breakthroughs in the study of animal language, and they are familiar with their subjects on a first name basis: Sarah, Lana, Kanzi, Koko, Sherman, Austin and Chantek.
Perhaps the best known critic of animal language is Herbert Terrace. Terrace's 1979 criticism using his own research with the chimpanzee Nim Chimpsky was scathing and spelled the end of animal language research in that era, most of which emphasized the production of language by animals. In short, he accused researchers of over-interpreting their results, especially as it is rarely parsimonious to ascribe true intentional "language production" when other simpler explanations for the behaviors (gestural hand signs) could be put forth. Additionally, his animals failed to show generalization of the concept of reference between the modalities of comprehension and production; this generalization is one of many fundamental ones that are trivial for human language use. The simpler explanation according to Terrace was that the animals had learned a sophisticated series of context-based behavioral strategies to obtain either primary (food) or social reinforcement, behaviors that could be over-interpreted as language use.
In 1984 Louis Herman published an account of artificial language found in the bottlenose dolphin in the journal Cognition. A major difference between Herman's work and previous research was his emphasis on a method of studying language comprehension only (rather than language comprehension and production by the animal(s)), which enabled rigorous controls and statistical tests, largely because he was limiting his research to evaluating the animals' physical behaviors (in response to sentences) with blinded observers, rather than attempting to interpret possible language utterances or productions. The dolphins' names here were Akeakamai and Phoenix. Irene Pepperberg used the vocal modality for language production and comprehension in a grey parrot named Alex in the verbal mode, and Sue Savage-Rumbaugh continues to study bonobos such as Kanzi and Panbanisha. R. Schusterman duplicated many of the dolphin results in his California sea lions ("Rocky"), and came from a more behaviorist tradition than Herman's cognitive approach. Schusterman's emphasis is on the importance on a learning structure known as equivalence classes.
However, overall, there has not been any meaningful dialog between the linguistics and animal language spheres, despite capturing the public's imagination in the popular press. Furthermore, the growing field of language evolution is another source of future interchange between these disciplines. Most primate researchers tend to show a bias toward a shared pre-linguistic ability between humans and chimpanzees, dating back to a common ancestor, while dolphin and parrot researchers stress the general cognitive principles underlying these abilities. More recent related controversies regarding animal abilities include the closely linked areas of theory of mind, Imitation (e.g. Nehaniv & Dautenhahn, 2002), Animal Culture (e.g. Rendell & Whitehead, 2001), and Language Evolution (e.g. Christiansen & Kirby, 2003).
There has been a recent emergence in animal language research which has contested the idea that animal communication is less sophisticated than human communication. Denise Herzing has done research on dolphins in the Bahamas whereby she created a two-way conversation via a submerged keyboard. The keyboard allows divers to communicate with wild dolphins. By using sounds and symbols on each key the dolphins could either press the key with their nose or mimic the whistling sound emitted in order to ask humans for a specific prop. This ongoing experiment has shown that in non-linguistic creatures sophisticated and rapid thinking does occur despite our previous conceptions of animal communication. Further research done with Kanzi using lexigrams has strengthened the idea that animal communication is much more complex than once thought.