Evolution of Communication in Primates

Evolution of Communication in Primates
by Sharon Mooney

"While our human awareness and compassion is rapidly expanding to include a greater concern for our biosphere and its inhabitants, our ignorance still remains a critical problem. Fundamental to removing ignorance and replacing it with understanding is communication. We feel that communication is the one behavior most critical for future survival. Washoe has helped replace some of our ignorance about communication with an understanding of ourselves, as well as other beings. This is one reason why we have committed our lives to a research project that focuses on the understanding of communication and chimpanzees."
-- Dr. Roger S. Fouts

Human – Ape Connection
Many studies have been conducted on the relationship between man and ape, and communication is only one of them. This paper focuses on the similarities between man and ape, our related abilities and need for communication. According to the latest research, Human and Chimp chromosomes are 1.23% different vs. the previously presumed 1.4% difference. According to the Jane Goodall Institute, Chimpanzees and humans possess similar biological traits in areas such as composition of blood and immune responses. Chimp and human brains and central nervous sytems are remarkably similar. Chimpanzees have been used in medical research because they are so biologically similar to humans. They can become infected with all known human infectious diseases with the possible exception of cholera. It is conceivable that Chimpanzees, Bonobo and Gorillas have the capacity for intellect that at one time was believed to be a unique human characteristic. Chimpanzees in captivity have successfully been taught such human language as American Sign Language and learning three hundred signs or more. Chimps have been able to master varied computer skills and chimps have the capacity "for reasoned thought, abstraction, generalization, symbolic representation and a concept of self". Researchers who have worked with the Chimpanzee and other apes express a firm belief their primate counterparts have a reasonable amount of ability to feel and express real emotion such as fear, sadness, despair and can feel both mental and physical pain. Some of the observable behavior includes "kissing, embracing, patting on the back, touching hands, tickling, swaggering, shaking a fist, brandishing sticks or hurling rocks. These patterns appear in similar contexts as those in which they are seen in humans and mean much the same thing." (Goodall, 1999) Chimpanzees have a closer relation genetically with humans than with gorillas. Some scientists have proposed classifying chimpanzees in a genus with humans, and dubbing them Homo troglodytes.

The Human and Chimp Brain are Similar
Scientists at Columbia, Mount Sinai have found a region called the planum temporale which is a part of the brain's temporal cortex, beneath the parietal cortex which is enlarged in humans and now known to share the same asymmetry in ninety four percent of chimpanzees. Scientists like Dr. Gannon believe that this new found evidence is potential proof that distinct planum temporale was a fundamental substructure in the brain of early man's and the great ape's (chimp, orangutan, gorilla) common ancestor, approximately eight to fourteen million years ago. This pre-hominid brain trait is believed to have diverged in its evolution from chimps when human ancestors moved away from localized territories and became roaming bipeds. It was believed that only humans possessed this enlargement. As noted, “Nineteenth-century neurologist Carl Wernicke had noticed that patients with brain lesions of the posterior temporal lobe and parietal lobe - the same area studied by the Mount Sinai and Columbia researchers - could produce language but couldn't understand it. It is likely that this region is responsible for handedness, musical talent, as well as communication disorders like schizophrenia and dyslexia. "Chimpanzees have a sense of self, a great cognitive capacity to understand a lot of things we teach them and the neurophysiology behind their communication ability is likely similar to our own." says Dr. Gannon. That region of the temporal cortex, also known as Wernicke's area, was thought to control language comprehension, but only in humans,” says Dr. Holloway. He expressed belief that perhaps chimpanzees do not have a language per se as humans but rather communicate by a complex combination of facial, body and hand expressions with the added impact of vocalizations such as grunts.

Dr. Gannon who assisted in the research at the Mount Sinai School of Medicine Department of Otolaryngology argues that "this evidence likely means that the anatomically distinct PT was already a fundamental neural substructure in the brain of a human - great ape (chimp, orangutan, gorilla) common ancestor around 8-14 million years ago. In fact, Dr James F. Battey, Jr., Director of NIH-NIDCD, has stated in an NIH press release "This study will generate language research from a new perspective."

At the Gombe Stream Reserve, near Lake Tanganyika chimpanzees have been observed to communicate by using a waving hand gesture to get other chimps to look in a certain direction or, using a “begging hand” to solicit a certain response from others. It can be deduced chimps have intelligence to judge the world around them, and the anticipated response of others around them. This recognition of chimps communicating effectively through hand gestures gave rise to the thought apes might understand sign language.

Efforts to teach Apes speech
Speech gave man the ability to evolve his self awareness, and by researching our cousins, the ape we can gain a better insight into how man’s ability to speak evolved. Early efforts were made to teach apes speech, but ended in failure. The results at best were near uninterpretable grunts. In difference to humans, chimps produce about twelve different vocalizations compared to the hundreds humans can make. When sign language was introduced to the ape subjects, successful breakthroughs resulted. Notably Koko a female gorilla taught American Sign Language to express her thoughts. Also, in the 1970’s a chimp called Washoe was trained in the University of Nevada. Washoe learned up to 240 words. Four other chimps were added to the sign language project and amazingly use their knowledge of sign language to teach one another. Washoe was documented to have taught her adopted son to sign without the interference of humans.

Many linguists believe apes have no real understanding of human language but are practicing imitation. They agree that apes may understand symbolism or individual words, they lack the ability to form a complex idea with syntax. Apes form language categories, for instance the word “dog” could represent all species of dogs, and the word “shoe” could represent either a boot or slipper. Apes might likewise invent a new word by combination of the old, for instance for “watermelon” they might say “drink fruit”. Apes can understand vocalized English and translate words into American Sign Language.

Some Benefits for Humans
Studying communication of apes has lead to some insight into teaching and better understanding what goes wrong with non communicating children to sign, autistic children and the developmentally disabled, even epilepsy. Dr. Daniel Buxhoeveden, physical anthropologist stated "We are trying to understand what makes the human brain different from non-human primates. We also are trying to understand the pathology of diseases of the brain that are not understandable by classical methods. We think the difference is going to be in the way the brain is organized." These researchers studied the organization of tissue, by completing detailed analyses of a "minicolumn" or a group of eight to one hundred brain cells and their wiring. Millions of such minicolumns exist throughout the brain, but this research was focused on the planum temporale. Differences exist in minicolumns of humans and ape. One of the researchers, Dr. Buxhoeveden stated "These minicolumns are different in their structure in the human brain and also different in that they are lateralized, larger on the left side than on the right side of the brain, we didn't find this in the chimpanzee or the monkey." In humans, language is controlled by the left side of the brain which makes the left-right brain difference pertinent. These differences may eventually help explain why humans possess advanced communications skills, compared to that of their primate counterpart, the ape, which possesses only basic communication skills. Dr. Buxhoeveden stated "We found evidence that the brain is organized differently in humans in this area of the brain, even though the outside looks the same. This provides an anatomical substrate, a hint that the brain is wired differently in humans in the language area than in the chimpanzee or the monkey." He continued to say, "We will be looking at this to describe pathologies that are subtle, that don't have classical symptoms that you see in diseases such as Alzheimer's, where there are obvious, major things wrong with brain tissue. In diseases such as schizophrenia and autism, those obvious symptoms aren't there. But we believe that you will find them in the most subtle wiring of the brain."

Literature Cited

No comments:

Post a Comment