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Animal Communication Studies & Language Comprehension

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 (Brandt, 2004). 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 (Brandt, 2004). This creates a form of communication through the series of interactions between the two via body language (Brandt, 2004). Through this body language, both humans and horses can express a wide range of emotions and desires (Brandt, 2004). It is through this body language that individuals are able to develop a sense of “horsemanship” (Brandt, 2004). 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 (Brandt, 2004). Conversely, horses are able to learn human body language and modify their behavior accordingly (Ladewig, 2007).

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 (Harley, 2010). 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 (Harley, 2010). Clever Hans could even answer these types of questions when not in the presence of his owner (Harley, 2010). 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 (Harley, 2010). As Hans neared the right answer, he was able to notice changes in the person’s facial expression and posture (Harley, 2010). As a result, he could either answer questions correctly or come very close to correct answers based on this reading of body language (Harley, 2010).

Dogs

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 (Soproni, 2001). Due this long period of human socialization, dogs have evolved to be better adapted to human environments than any other animal (Soproni, 2001). Dogs have proven to be very sensitive to human gestures, such as pointing, nodding and gaze direction (Soproni, 2001). By comparison, other animals like monkeys are extremely limited in their ability to correctly respond to these same signals (Soproni, 2001).

During a series of experiments with 8 different female dogs, researchers tested the dogs’ ability to correctly find hidden bait based on the trainer’s gestures (Soproni, 2001). 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 (Soproni, 2001). All of the dogs demonstrated the ability to correctly identify the correct bowl based on pointing and gaze, however the eye-only gesture trials dogs were not able to successful understand the cue (Soproni, 2001). 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 (Soproni, 2001). 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 (Soproni, 2001).

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 (Kamanski, 2004). Experiments conducted with Rico prove that he has the ability to correctly distinguish between 10 different items at once with high rates of accuracy (Bloom, 2004). Through multiple trials, researchers were able to establish that Rico has a vocabulary of about 200 words (Bloom, 2004). What is most unique about Rico is that he has demonstrated the ability for “fast mapping”; an ability not even primate animal subjects show (Bloom, 2004). 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 (Bloom). From an early age, children show a broad range of meaning for words, including different word forms like verbs, adjectives and nouns (Kamanski, 2004). Yet children can understand the meaning of new words in a wide range of context and Rico’s abilities only apply when fetching objects (Bloom, 2004). However, psycholinguists argue that Rico is still learning language the way a child does, he is just limited in his learning capacity (Bloom, 2004). Another caveat to this study is that Rico’s owner is the only person naming the objects (Bloom, 2004). 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 (Bloom, 2004). Further research plans to test Rico’s ability to recognize words from different speakers (Bloom, 2004).

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 (Kamanski, 2009). 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 (Kaminski, 2009). 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 (Kamanski, 2009). 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 (Kamanski, 2009).

The second experiment consisted only of the three language trained dogs: Rico, Betsy and Paddy (Kaminski, 2009). 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 (Kaminski, 2009). 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 (Kaminski, 2009). 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 (Kaminski, 2009).

The third experiment consisted of a learning phase, followed by a retrieval phase that came exactly one minute later (Kaminski, 2009). During the learning phase the dogs were each shown a photograph of a new object with a novel label (Kaminski, 2009). 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 (Kaminski, 2009). Betsy showed the highest rates of successful retrieval, however she could only use the exact replica of the object to identify it (Kaminski). Also, he accuracy rate was still below that of chance (Kaminski, 2009).

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 (Kaminski, 2009). The researchers think that the dogs were learning the meaning of objects through communicating with their owners, even though their comprehension abilities are limited (Kaminski, 2009). Interestingly, like children, dogs have difficulty discriminating between dual representations of objects (Kaminski, 2009). The researchers hypothesize that children have difficulty identifying an object based on a photograph because they cannot physically manipulate the object (Kaminski, 2009). Dogs function in the same manner, which is why the border collies in this study had difficulty correctly retrieving objects based on their photographs (Kaminski, 2009).

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 (Kaminski, 2009).

Primates

Like songbirds, primates show the use of phonological syntax in their call combinations (Crockford, 2005). These call combinations are used to communicate with other primates in their social community (Crockford, 2005). Call combinations also use grunts, barks and screams to convey different information, suggesting a primitive form of lexical syntax (Crockford, 2005).

Studies conducted with tamarin monkeys suggest that these monkeys show some sense of categorical perception (Ramus, 2000). In these studies, the tamarins were placed in front of a loud speaker while both Dutch and Japanese was spoken through the speaker. The tamarin’s 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 (Ramus, 2000). Results indicate that there was a significant correlation between head orientation and spoken language, suggesting the monkeys do posses categorical perception (Ramus, 2000). 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 (Ramus, 2000). However, differences between the systems exist as well. The tamarins were less sensitive to prosody changes in comparison to infants (Ramus, 2000). Tamarin monkeys however have little need for speech, which suggests that human speech perception may be more sensitive as a result of evolution (Ramus, 2000).

Kanzi

The most prominent ape in primate language studies is a bonobo named Kanzi (Wynne, 2007). Researchers began studing Kanzi’s language abilities since he was around sixth months old (Wynne, 2007). His adoptive mother, Matate was originally the researchers’ main focus (Wynne, 2007). Matata was trained using Duane Rumbaugh’s Yerkish lexigram system, however she was never able to successfully learn this system (Wynne, 2007). However, one day Kanzi was left alone one day with the lexigram keyboard used for this system and began composing sentences (Wynne, 2007). Kanzi was not formally trained during this time, so he appears to have learned the language simply by observing Matata interact with the researchers (Wynne, 2007).

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 (Wynne, 2007). 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 (Savage-Rumbaugh). Kanzi is unable to produce speech vocally, but possesses all the cognitive abilities required for primitive speech production (Savage-Rumbaugh).

Kanzi’s language abilities are very limited, it is important to note that there is some evidence he understands 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 (Wynne, 2007). When Kanzi asked for this treat, he was told that he had to wait until one of the staff members returns (Wynne, 2007). In response, Kanzi pressed the lexigram for pear (Wynne, 2007). Kanzi typically only would press “pear” when he knew pears were available for him to eat (Wynne, 2007). However, the staff member who Kanzi had to wait for was Pär Segerdahl, whose first name is like as “pear” in English (Wynne, 2007). Kanzi also uses “pear” when asking for someone to get his treat (Wynne, 2007). Researchers think that Kanzi was using the lexigram for pear to refer to Pär Segerdahl (Wynne, 2007). 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.