User:Mdf256/sandbox


 * This is our sandbox for the Animal Language Wikipedia page. We edited 3 sections: Aspects of Human Language, Non-Primates: Studied Examples, and Primates: Studied Examples. The other sections are copied from the original page.

Animal language is the modeling of human language in non human animal systems. While the term is widely used, researchers agree that animal languages are not as complex or expressive as human language.

Some researchers including the linguist Charles Hockett, who proposed a list of design features of Human Language, argue that there are significant differences separating human language from animal communication even at its most complex, and that the underlying principles are not related. Accordingly, Thomas A. Sebeok has proposed not to use the term 'language' in case of animal sign systems.

Others argue that an evolutionary continuum exists between the communication methods these animals use and human language. Examining this continuum could help explain how humanity evolved its incredibly sophisticated proficiency for language.

Aspects of human language
The following are properties of human language identified by Charles Hockett. However, many if not all of these design features of language can also be found in animal communication. A list of those which pertain to this page is as follows:


 * 1. Mode of Communication: the means by which an organism conveys information.
 * 2. Rapid Fading: a conveyed message does not exist indefinitely.
 * 3. Interchangeability: speaker can create a message and receiver can send back messages in the same manner.
 * 4. Feedback: those who communicate are internally aware of the message they are sending and can correct themselves.
 * 5. Specialization: the apparatus that creates the sound, and the sound itself, are used for communication.
 * 6. Semanticity: language is symbolic.
 * 7. Arbitrariness: there is no inherent connection between a signal and its meaning. Meaning is imposed on the signal by the users of the language.
 * 8. Discreteness: each unit of language can be separated.
 * 9. Displacement: language can refer to things that are not present.
 * 10. Productivity: users of a language can create and understand novel messages.
 * 11. Cultural Transmission: language is socially acquired.
 * 12. Duality: smaller signals (e.g. sounds) compromise larger signals (e.g. words, sentences).
 * 13. Prevarication: language can be deceptive or meaningless.
 * 14. Reflexiveness: meta-linguistic ability- the ability to talk about language.
 * 15. Learnability: knowing a language implies one can acquire another language.

Call Combinations in Wild Chimpanzees
Like songbirds, primates show the use of phonological syntax in their call combinations. These call combinations are used to communicate with other primates in their social community. Call combinations also use grunts, barks and screams to convey different information, suggesting a primitive form of lexical syntax.

Tamarin Monkeys & Categorical Perception
Studies conducted with tamarin monkeys suggest that these monkeys show some sense of categorical perception. In these studies, the tamarins were placed in front of a loud speaker while both Dutch and Japanese was spoken through the speaker. The tamarins' ability to distinguish between spoken Dutch from Japanese was measured by whether or not they looked at the loud speaker when switch between languages occurred. Results indicate that there was a significant correlation between head orientation and spoken language, suggesting the monkeys do posses categorical perception. Interestingly, the results from the tamarin monkeys closely matches the results of similar experiments conducted with infants, indicating that primate and human auditory systems are very similar in design. However, differences between the systems exist as well. The tamarins were less sensitive to prosody changes in comparison to infants. Tamarin monkeys however have little need for speech, which suggests that human speech perception may be more sensitive as a result of evolution.

Gua
In one of the earliest chimpanzee intervention studies, the Kellogg family raised a 7 and a half month old female chimpanzee named Gua in their home along with their 10 month old son Donald. The duration of the study, Gua was incapable of producing anything other than chimpanzee vocalizations due to her vocal tract’s limited articulation and phonation abilities. Despite her limited production abilities, her comprehension skills in the beginning of the study were comparable and even superior to Donald’s. After a while, human language comprehension facilities proved themselves to be superior and Donald understood significantly more words than Gua and could produce his own utterances. The experiment was terminated after Donald began mimicking Gua’s vocalizations.

Viki
In another early cross-fostering chimpanzee study, Keith Hayes reared a chimpanzee in his home from infancy named Viki. Language articulation limitations of the chimpanzee vocal tract were again demonstrated in this study as Viki was only able to poorly articulate four words at the end of a 6 year period: “mama”, “up”, “cup”, and “papa”. While the researchers claimed that Viki could comprehend a wide array of words, it is unclear whether Viki was actually showing comprehension of the words she heard or the researchers became so accustomed to Viki’s behaviors that they misinterpreted some of her neutral mannerisms as understanding due to the largely anecdotal nature of the literature.

Washoe
Beatrix and Allen Gardner were among other researchers to complete a chimpanzee cross-fostering study. Rather than attempting to teach their female chimpanzee, Washoe, vocalized human language, they sought to teach her American Sign Language, taking into account differences in the chimpanzee vocal tract that severely limited earlier cross-fostering studies. This proved to be advantageous for the researchers, as Washoe was able to develop a syntactically complex vocabulary of 200 words. Like human children, she could also make errors in which she overgeneralized meaning (she called a cow, also a four legged animal, a “dog”) and combine words into short, meaningful strings of utterance. Critics of the Gardners’ study state that a corpus of Washoe’s utterances was not kept and that only his successes with using ASL were put into the literature Additionally, Washoe’s utterances did not employ a consistent grammatical system and she could not combine her short utterances into more complex sentences Although Washoe was able to employ many of Hockett’s design features of language, such as semanticity, she still wasn’t able to make use of feedback, full use of arbitrariness, productivity, and reflexiveness.

Nim Chimpsky
In “Project Nim”, Herbert Terrace of Columbia University attempted to teach Nim Chimpsky the chimpanzee American Sign Language limitations of the Washoe study into account, the researchers on “Project Nim” recorded all of Nim’s uses of language rather than just his successes. Nim was able to employ regular two-word phrases in which he used his knowledge of 125 signs. However, when producing longer strings, utterances were highly repetitive and much unlike human speech. Additionally, he often did not spontaneously sign, but rather signed only did when prompted to by the researchers. A significant number of his utterances were merely repetitions of what the researchers had just said to him. Nim also was not tested and taught ASL in a natural setting, but in a controlled laboratory setting, which made the means by which Nim learned the language lacked traditional transmission. Additionally, there was no feedback and reflexiveness. Because of these limitations, Terrace remained unconvinced that chimpanzees could learn human language and ended his experiment.

Kanzi
The most prominent ape in primate language studies is a bonobo named Kanzi. Researchers began studing Kanzi’s language abilities since he was around sixth months old. His adoptive mother, Matate, was originally the researchers’ main focus. Matata was trained using Duane Rumbaugh’s Yerkish lexigram system, but she was never able to successfully learn this system. One day Kanzi was left alone one day with the lexigram keyboard used for this system and began composing sentences, so needless to say, he became the researchers' new focus. Kanzi was not formally trained during this time, so he appears to have learned the language simply by observing Matata interact with the researchers.

Kanzi, who is now 31 years of age, has a vocabulary of approximately 1,000 English words and can use around 250 lexigrams to compose sentences. Although a primate’s brain is not pre-configured to understand language, Kanzi’s brain clearly demonstrates a capacity for vast information integration – something essential for language comprehension. Kanzi is unable to produce speech vocally, but possesses all the cognitive abilities required for primitive speech production.

Although Kanzi’s language abilities are very limited, it is important to note that there is some evidence he understands that a word can have multiple meanings. One of the authors of the book “What The Ape Said”, which focuses on Kanzi’s language abilities, is a woman named Pär Segerdahl. During her first visit to the Language Research Center, one of the researchers hid a treat for Kanzi as a special reward. When Kanzi asked for this treat, he was told that he had to wait until one of the staff members returns. In response, Kanzi pressed the lexigram for the word pear. Kanzi typically only would press the lexigram for pear when he knew pears were available for him to eat. However, the staff member who Kanzi had to wait for was Pär Segerdahl, whose first name is pronounced like “pear” in English. Kanzi also uses “pear” when asking for someone to get his treat. Researchers think that Kanzi was using the lexigram for pear to refer to Pär Segerdahl. Although this does not provide any solid evidence that Kanzi learned to use the word pear in a different context, it seems highly unlikely that he was simply using this word coincidentally.

Dolphins
Dolphins are known to use clicks and whistles to communicate amongst themselves but these sounds are generally not accepted by the scientific community as characterizing a language. However, there have been several research studies which have attempted to teach relatively complex language abilities to dolphins. A number of these studies have been led by Louis Herman.

In one of Herman’s studies, dolphins were trained to differentiate between the semantics of the commands, "surfboard person fetch" (bring the person to the surfboard), and "person surfboard fetch" (bring the surfboard to the person). In another study, it was shown that dolphins understood that the gestures made by the human trainers were symbolic of the meaning they represented. In animal studies it has often been questioned if an animal truly understands that a symbol is a representation, or if the animal only understands that the symbol precedes an action. For example, if a bird pecks a picture of the word "FOOD" and receives a seed each time, it is unclear whether the bird understands that "FOOD" represents the seed and so by pecking at "FOOD" it is asking for a seed, or if the bird simply understands that if it pecks some area of the ground it receives a seed. In one of Herman’s studies with the dolphin Akeakamai, the dolphin was able to correctly respond yes or no when trainers used a symbolic gesture representing an object to ask if that object was present in Akeakamai’s water tank. In order to correctly respond about an object that was not present, Akeakamai had to understand that the symbolic gesture represented the object.

These findings clearly demonstrate Hockett’s design features of semanticity, arbitrariness, and displacement. Semanticity is show in that the gestures learned symbolized actions or objects. The fact that the gestures did not have a meaning inherent to the objects they represented demonstrates arbitrariness. Displacement is also demonstrated because objects that were not in Akeakamai’s tank were referred to. While the dolphins may not use these features in their natural communications, the fact that they are able to learn such features tells us that language abilities are not unique nor solely reserved for humans.

Caribbean Reef Squid
In summary, the Caribbean Reef Squid seem to have their own “language” which uses signals to constitute vocabulary. Scientifically referred to as cephalopods, the Carribean Reef Squid are able to produce different display patterns on their skin (Mather, 2010). These patterns are useful when escaping from various, potentially dangerous, animals. Additionally Mather, Griebel, and Byrne (2010) believe that this specific ability is “important for communication”.

Some may argue that this form of communication resembles a “language”. In relation to Hockett’s design features, Carribean Reef Squid may indeed be demonstrating arbitrariness through this type of communication. However, upon examining Hockett’s other features, it becomes apparent that these squid fail to demonstrate any other aspects of “language”. For example, the squid are limited in their producticity--being only able to create about four colors. With only four colors to choose from, the squid are left without many options to convey a message to a receiver. Along the same lines, the receiver of the squid’s signal may not understand what the squid is doing and vice versa. If another animal signals to the squid in their own form of “communication” it may be likely that the squid does not understand. Furthermore, the squid will probably not be able to learn a “new” language--failing to demonstrate learnability.

Parrots
Studies of the African Grey Parrot, Alex were conducted over 30 years by Irene Pepperberg. After 26 months of training, Alex was able to identify 9 physical items: paper, key, wood, hide (rawhide chips), peg wood (clothes pins), cork, corn, nut, and pasta (bow-tie macaroni). He was also able to label 3 colors, rose for red, blue, and green. Alex was able to label “three-corner” and “four-corner” respectively for triangles and squares, and even had a limited function of “nuh” for No. Alex correctly answered on his first try 80% of all objects presented in 200 tests; and he scored 78% when all presentations were included.

What about the question, do birds contain the ability for categorical perception? Alex was formally tested again in 170 tests that would require Alex to answer either “what color?” or “what shape?” the object was that was being presented to him. His results were once again over 80%, with 84.7% correct for color queries, and 83.7% correct on shape queries, even with learning several new labels as “yellow, grey, two-corner, and five corner”. Most importantly was that Alex could reclassify any object that he was presented with, whether it was immediately during the study or even in presentations several days later.

Alex also posses a complex acoustic map between  the human system and his own because similar to humans he was able to  produce new human speech patterns from existent ones. Evidence also suggests that Alex may exploit anticipatory co-articulation and data on his solitary sound that Alex may engage in top-down processing. Data from Pepperberg also suggests that voluntary control of portions of the vocal tract for linguistic ends is not a unique human characteristic. There is evidence that at least Grey parrots like humans can use phonetic distinctions to produce meaningful sounds that are “largely independent of affect and psychological state.”

Starlings
The study done by Gentner, et. al. suggests that Starlings have some understanding of recursion. The starlings seemed to recognize the difference between finite state grammar (ABAB) and phase structure grammar (AABB) patterns within song sequences. Further experiments within the study tried to rule out the possibility or primacy; only learning the first 2 units of a pattern, or recency; only learning the last 2 units of the pattern.

Songbirds also seem to go through a sensitive learning period, similar to young children. Birds raised in isolation from early ages without outside contact with wild birds will have severely less songs in their collection, compared to wild birds who can have a variety of 20 to 30 different songs. This is similar to children who develop in abusive homes who are cut off from contact with others and thus show hampered social and language skills.

This evidence also suggests that songbirds have both innate and learned components of speech. While starlings posses the innate ability to create and sing songs, through interaction with other birds they learn more songs which suggests that there are also learned components of songbird communication.

Ants
While many species unintentionally use pheromones as a method of chemically communicating with other organisms, ants intentionally drop pheromone particles to communicate with other ants. Specifically, ants such as the ponerine ant lay pheromone trails to food sources (Pratt, S.C.). As ants leave their hill, they leave a chemical trail on the ground signalling the direction they travel in. Once food is found, they travel back to the colony along that same path, strengthening the chemical scent on the specific path to the food source. As other ants detect the laid pheromone scent, they also travel along the trail and add their pheromones to it, strengthening the chemical trail even more. While ants display the Hockett design feature of a chemical mode of communication, ant communication lacks productivity, semanticity, and interchangeability due to the fact that the only message that is able to be transmitted is direction of food sources. Based on research evidence, it does not seem as though pheromones are used to transmit other novel messages.

Bees
Bees, scientifically referred to as Anthophila, communicate with other bees by altering the direction of a characteristic “dance” once they return to the hive. Researchers believe this dance points other members of the hive towards the direction of food. The longer the dance, the further the food is from the hive demonstrating symbolicness and semanticity.

Researcher Tim Landgraf and colleagues from Berlin have created a robotic bee which was made to mimic this “dance”. The researchers claim that this robotic bee smells, flies, and sounds like a true honeybee. Findings from these trials suggest that the other bees did, in fact, respond to “Robobee” by fleeing the hive they were trained to live in in search of other food (which Robobee had suggested). However, the bees soon returned to their old hives as the researchers believe that the bees did not understand where Robobee told them to go. Additionally the researchers note that bees are selective when choosing to pay attention to other bee’s dances. If food sources have dried, bees are more likely to respond to another bee’s dance.

In relation to Hockett’s design features of language, bees demonstrate interchangeability (bees can send a message and other bees can comprehend it). They also demonstrate symbolicness (semanticity) because the direction and speed of their “dance” convey different meanings. However, this “dance” does not resemble language because it is limited in productivity--only a handful of messages can be sent or received. Additionally, bees cannot learn another form of communication--failing to demonstrate learnability.

Rats
Recent research has suggested that rats are capable of understanding and transferring patterns used in language once thought to be specific to humans, such as the pattern XYX. Researchers operantly conditioned rats to recognize specific stimuli sequences and then tested to see whether the rats were able to generalize what they’d learned to novel patterns. The stimuli were either visual, in the form of differential levels of light, or auditory, in the form of pure tones. After several trials of operant conditioning, the rats were able to recognize and generalize the patterns at a statistically significant rate.

Chinchillas
Kuhl & Miller (1975) trained chinchillas to distinguish naturally produced syllables /l/ and /d/. They then classified these sounds produced by new talkers, who they were not trained by. Voice onset time may be key in distinguishing sounds for both humans and chinchillas, considering each have similar VOT distinguishing patterns on the task.

This ability to distinguish different sounds, produced by different people, relates to Hockett's feature of language called learnability. Because chinchillas are not aware that what they are learning are, in fact, aspects of language, one may say that they have demonstrated learnability. They are able to distinguish sounds produced by different speakers (who really, to a chinchilla, could be speaking an entirely different language).

Horses
Humans have used horses for centuries as a form of transportation, and out of this a unique bond has been formed between humans and horses. A notable difference between human and horse relationships is the fact that there is a large amount of physical contact, since people ride on the backs of horses. This creates a form of communication through the series of interactions between the two via body language. Through this body language, both humans and horses can express a wide range of emotions and desires. It is through this body language that individuals are able to develop a sense of “horsemanship”. Furthermore, people who observe horse-to-horse communication are able to gain a better sense of what the horse’s body language is intended to convey. Conversely, horses are able to learn human body language and modify their behavior accordingly.

Clever Hans
At the beginning of the 20th century, a horse from Germany appeared to have the ability to comprehend language and even answer simple questions. Mr. Von Osten claimed that his horse named Clever Hans was able to solve simple arithmetic problems and report the time of day by stomping his hoof. Clever Hans could even answer these types of questions when not in the presence of his owner. This all strongly suggests the capacity for basic language comprehension in Hans, however it was later discovered that what he was actually extremely sensitive to the body language of the person asking the questions. As Hans neared the right answer, he was able to notice changes in the person’s facial expression and posture. As a result, he could either answer questions correctly or come very close to correct answers based on this reading of body language.

The Use of Visual Cues
Given their long history living with humans in societies (approx. 10,000 years) psycholinguists note that dogs have a unique ability to read human communicative signals. Due this long period of human socialization, dogs have evolved to be better adapted to human environments than any other animal. Dogs have proven to be very sensitive to human gestures, such as pointing, nodding and gaze direction. By comparison, other animals like monkeys are extremely limited in their ability to correctly respond to these same signals.

During a series of experiments with eight different female dogs, researchers tested the dogs’ ability to correctly find hidden bait based on the trainer’s gestures. Pieces of food were hidden under two empty bowls and the dogs were given the choice of correctly identifying the bowl with the food based on pointing gestures and directional gaze. All of the dogs demonstrated the ability to correctly identify the correct bowl based on pointing and gaze, however for the eye-only gesture trials all eight dogs were not able to successful understand the cue. This suggests that dogs are relying on the orientation and direction of body parts to locate objects, and that they do not specifically understand their meaning. Although they may not understand the exact meaning of individual gestures, the researchers note that the dogs all seem to understand that the gesture is intended to communicate some kind of information.

Rico
Rico is a Border Collie that is not like your average dog. According to his owners, Rico first demonstrated the ability to correctly fetch items by name at around 10 months of age. Experiments conducted with Rico prove that he has the ability to correctly distinguish between 10 different items at once with high rates of accuracy. Through multiple trials, researchers were able to establish that Rico has a vocabulary of about 200 words. What is most unique about Rico is that he has demonstrated the ability for “fast mapping”; an ability not even primate animal subjects show. When shown a new object among seven familiar objects, Rico understands that new words he hears most likely refer to the new object, much like how human children learn language. From an early age, children show a broad range of meaning for words, including different word forms like verbs, adjectives and nouns. Yet children can understand the meaning of new words in a wide range of context and Rico’s abilities only apply when fetching objects. However, psycholinguists argue that Rico is still learning language the way a child does, he is just limited in his learning capacity. Another caveat to this study is that Rico’s owner is the only person naming the objects. Critics suggest that we are merely seeing another example of the “Clever Hans effect”, where Rico is responding to the subtle cues of his owner. Further research plans to test Rico’s ability to recognize words from different speakers.

Other Border Collie Studies
Other Border Collie studies have been conducted to see what language abilities generalize to dogs. In a series of experiments, researchers tested object recognition by the dogs in three different scenarios. Rico was actually one of the male dogs used in these experiments, which allowed researchers to make a direct comparison of his abilities with the other Border Collies.

In one experiment conducted with five adult Border Collies (3 males and 2 females), researchers wanted to see if the dogs could correctly fetch objects based on the context of the object. The dogs were shown an object, then asked to retrieve an exact replica of the object, a miniature replica and a photograph of the object all during separate trials. Three of the dogs in this study were language trained, while two were not. The results of this experiment showed that only the three language trained dogs could correctly retrieve objects well above chance based on the exact replica object. Only one dog from the language-trained group, one of the females named Betsy, was able to correctly retrieve objects based on the photograph of that object.

The second experiment consisted only of the three language trained dogs: Rico, Betsy and Paddy. In this experiment, the dogs were shown an object and then given a choice between the exact replica and photograph of the object for retrieval. One variation used for the photographs in this study however was that the photographs were shown upright on a stand, making them easier for the dogs to identify. The results of this study showed high rates of successful retrieval for all dogs, however all three showed a strong preference for the identical sized replica over the photograph when retrieving the appropriate object.

The third experiment consisted of a learning phase, followed by a retrieval phase that came exactly one minute later. During the learning phase the dogs were each shown a photograph of a new object with a novel label. After 60 seconds passed, the dogs were then told by their owners to retrieve the target object from a set of four different replica objects, each of which having its own photograph nearby. Betsy showed the highest rates of successful retrieval, however she could only use the exact replica of the object to identify it. However, he accuracy rate was still below that of chance.

Although the Border Collies used in this series of experiments could only correctly identify objects based on seeing an exact replica, researchers believed the dogs were actually learning the meaning of the objects rather than simply matching visual stimuli. The researchers think that the dogs were learning the meaning of objects through communicating with their owners, even though their comprehension abilities are limited. Interestingly, like children, dogs have difficulty discriminating between dual representations of objects. The researchers hypothesize that children have difficulty identifying an object based on a photograph because they cannot physically manipulate the object. Dogs function in the same manner, which is why the Border Collies in this study had difficulty correctly retrieving objects based on their photographs.

From these Border Collie studies, researchers conclude that dogs demonstrate greater language comprehension abilities compared to apes because of their adaptation to human societies as well as their unique ability to read human facial expressions and other visual cues.

Butterflies
According to Nijhout (1991) butterflies are unique in that they are able to camouflage, mimic, or compete using their wing patterns. Wing eyespots are used to mimic the appearance of predator eyes, used mainly to avoid attack.

With regards to Hockett's design features of language, butterflies exemplify prevarication. Because their wing patterns give off a signal saying they are not what they really are (usually their wing patterns mimic "eyes" of a predator), they are being deceptive in their communication.

Comparison of the term with "animal communication"
It is worth distinguishing "animal language" from "animal communication", no matter how complex the latter may be. In general the term "animal language" is reserved for the modeling of human language in animal systems; though there is some comparative interchange in certain cases (e.g. Cheney & Seyfarth's vervet monkey call studies). Thus "animal language" typically does not include bee dancing, bird song, whale song, dolphin signature whistles, prairie dogs, nor 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), is today not 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.) In the 1970s John Lilly was attempting to "break the code": to fully communicate ideas and concepts with wild populations of dolphins so that we could "speak" to them, and share our cultures, histories, and more. This effort failed. The very early [chimpanzee] work was with 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, as well as no voluntary control of their breathing. This combination made 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 laden with buttons adorned 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 basically 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. Also, 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 1985 during this anti-Animal Language backlash, Louis Herman published an account of artificial language in the bottlenosed 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 researchers 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 an African 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. Also, 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).

Researchers

 * Louis Herman
 * Roger Fouts
 * Deborah Fouts
 * Mary Lee Jensvold
 * John Lilly
 * Irene Pepperberg
 * David Premack
 * Sue Savage-Rumbaugh
 * Thomas A. Sebeok
 * Erich Jarvis
 * Noam Chomsky

Animals

 * Akeakamai
 * Alex (parrot)
 * Batyr
 * Clever Hans
 * Greater Spot-nosed Monkey
 * Kanzi
 * Nim Chimpsky
 * Koko
 * N'kisi
 * Panzee and Panbanisha
 * Washoe (chimpanzee)
 * Parrots, hummingbirds, songbirds