A Rhapsody of Words
Language is the way we as humans interact with the world. We use it to communicate with each other about the present, to speculate about the future, and to write down our past so it will not be forgotten. No other species is able to do this. Language is truly what separates us from the rest of the animal kingdom. But how did this incredible ability evolve, and why is it not observed in other creatures? There are many theories about the development of language, but I believe that it is the chance product of a complex and tireless brain constantly searching for connections.
The theory currently held by most scientists is that of neo-Darwinism. This is the belief that language evolved by natural selection, just as any other trait. Though no other animal possesses true language as humans do, research has revealed that chimpanzees and bonobos, our closest relatives, share certain neural characteristics with humans related to language (1). In humans, two areas in the left hemisphere are very involved in the production of speech: Broca’s area and Wernicke’s area. Both these areas are larger than the corresponding areas of the right hemisphere. Though these areas do not control language in chimps and bonobos, the corresponding areas are larger in the left hemisphere than in the right, suggesting that a common ancestor had a brain with this asymmetry. Many scientists take this to mean that this common ancestor’s brain developed language as it evolved into the modern human brain. Chimps and bonobos still have these asymmetrical areas, but they never evolved into Broca’s area and Wernicke’s area as they did in humans.
The other and more controversial theory is that of exaptation; language developed over a much shorter period of time as the side-effect of other traits that had been naturally selected for. Stephen Jay Gould describes this as a spandrel: something that had originally developed for one purpose, but then became used for something else. Cranial endocasts of fossilized human skulls show that over time, certain areas of the parietal, temporal, and occipital lobes developed and eventually fused together into Broca’s area and Wernicke’s area (2). These areas were most likely involved in tool making, problem solving, and other survival skills, but they developed so much that new neural pathways were created. In fact, many neural pathways shared by humans and other primates appear to have similar functions in all species, plus language function in humans, suggesting that language is a byproduct of the development of these pathways. Noam Chomsky describes this as the “hopeful monster” theory (3). Human beings were lucky enough to evolve a set of mental skills that happened to produce language when combined. Natural selection played a part in developing the individual skills, such as problem-solving and creativity, but it was chance that language developed from them.
Though neither theory can definitely be proved or disproved, the idea of natural selection creating language does not seem to have enough evidence to support it. As both the great apes and humans share hemispheric asymmetry, both had the groundwork to develop complex language centers in the left hemisphere, yet only humans did. Other primates, sharing similar environments, only developed the more basic skills of tool-making and problem-solving. It does not seem likely that very similar species in similar environments would not develop similar mental skills in response to evolutionary pressures. If neo-Darwinism is to be believed, there must be evidence that language evolved for a survival reason, yet other primates have successfully evolved without it. Many animals have very elaborate methods of communication, such as the intricate dances of honey bees to inform the hive of the location of pollen, but these skills cannot be said to be true language. There are no species at the half-way point, either, no animals with a very primitive form of language that could be said to be evolving along a trend toward human language. Human beings are the anomaly, not the endpoint of a continuum of language evolution.
Though the majority of scientists would disagree, I personally believe that exaptation is better able to explain the vast differences between animal communication and human language. The explanation is that there is no explanation; language developed purely by chance, not because it was naturally selected for. It is the lucky byproduct of the evolution of other skills. The chance of language developing so spontaneously under very specific neural conditions is highly improbable, and that is precisely why it can explain human language. There is a huge number of species of animals in the world, yet only humans developed language. That must be because the development of language was so unlikely. If natural selection had played a role in developing language, then surely other animals under the same evolutionary pressures as humans would have developed a similar skill, or at least a sort of pre-language. Many other mammals, primates in particular, have similar brain structures to human brain structures, and therefore the potential to develop language centers, but they never did. Language development in humans seems like a chance occurrence, especially considering that humans had in fact already developed a method of communication by natural selection; we just do not use it as much as we once did.
The gesture-call system is a method of communication used by monkeys and gibbons (1). The midbrain controls gestures and vocalizations used to relay information such as warnings, threats, and emotions. This is how most other primates communicate with each other. The gestures and vocalizations are a form of communication, but they are not language. They can only express factual information; they cannot use this system to tell stories, persuade, or postulate. Because the gesture-call system communicates information vital to survival, it is safe to assume that it evolved by natural selection. To a degree, this system still exists in humans (1). Laughter, sobbing, facial expressions, and gestures are partially controlled by the midbrain, and are instinctual reactions to certain situations. Though these all play important roles in human communication, it is language, driven by the neocortex, that truly allows humans to interact in ways very different from those of other animals. If the gesture-call system evolved by natural selection in other primates and never developed into language, then it is logical to assume that the language that appeared in humans was a luxury, rather than a necessity for survival.
How could language with all its complexities even evolve by natural selection? If all the information necessary for survival can be communicated through the gesture-call system, why would language be any more useful? Obviously, having enough distinct words to cover the sources of danger, food, and mates would have an evolutionary advantage, but why develop something as complex and often illogically structured as language? Does the prehistoric human with a vocabulary of twenty words have an evolutionary advantage over one with only nineteen?
At this point, it becomes necessary to more clearly differentiate between communication and language. For the purposes of this argument, communication will be defined as the relay of information from one animal to another, be it through vocalizations, gestures, facial expressions, or movement. For social animals, communication is necessary for survival. Language takes communication further, incorporating some unique properties. Language consists of a lexicon of discrete words (that may be gestures or symbols as well as vocalizations) that can be arranged in sentences. These sentences have a preferred word order and are recursive, meaning that an infinite number can be made with the same structure (4). Language can be used to relay information, but it can also be used to verbalize what does not exist or is not present (5). It can be used to generate ideas, remember the past, and speculate about the future. No other animal is known to do this.
Many people are intrigued by the idea that other primates can be taught language, such as American Sign Language. Indeed, many successful studies have been done to teach gorillas, chimpanzees, and bonobos a number of words that they can both understand and use. But are they truly using language? One such study, performed by Savage-Rambaugh, was done with Kanzi, a young bonobo. Kanzi was taught to use a twelve-symbol keyboard to make up to 120 different phrases of up to three words each. Eventually, Kanzi could even understand and carry out simple spoken requests (1). But Kanzi never questioned or elaborated on these requests (6). The requests were treated as a simple relay of information, just as the gesture-call system might be used to communicate information. In all of these types of studies, other primates have learned to recognize certain words and to express basic emotions and describe situations, but never to use language creatively. Language in the hands of humans develops far more subtleties and complexities.
For most of its history, Nicaragua had no national sign language. Many deaf children had no exposure to language at all. In 1977, an elementary school for the deaf was set up in Managua. Children with absolutely no knowledge of language interacted with each other, first through simple gestures and facial expressions, but then through something more. They began to create their own language: Nicaraguan Sign Language. Each generation of children to pass through the school has added its own complexities to NSL, making it a true language with discrete words and intricate grammar rules (7). A study was conducted, comparing deaf children who had grown up signing NSL to hearing Spanish-speakers. They were shown a cartoon depicting a cat rolling down a hill and were asked to describe the motion using only hand gestures. The hearing individuals made circular motions with their hands, simultaneously moving their hands downwards. The deaf children made two different gestures: the NSL sign for rolling, and the NSL sign for downwards (8). The gestures of the hearing people were merely illustrations of what they had seen, simple communication. The gestures of the deaf children were discrete words, words that could be used in an infinite number of phrases to express many theoretical situations. The hearing people in this study are like Kanzi, only able to express basic information using the gesture-call system. The deaf people are using language.
When living in a social situation, people will develop language, just as the Nicaraguan children have done. When other primates are living together, they simply use the gesture-call system. They may be taught to understand a few words of a human language, but in the wild, they will not develop a language of their own. Perhaps language is not necessary. Communication enables animals living together to give warnings, threaten enemies, and to hunt or find food as a group. All of these are necessary for survival. Language enables humans to tell stories, worship gods, and wonder if it will rain tomorrow. These are not necessary for survival. Is a human who makes up a creation myth better able to feed himself? Is a human who composes a poem about a tree better able to evade predators? Clearly not. Though a large part of language is the communication of important information, I propose that what sets it apart from the communication of other animals is the component of imagination.
The human brain evolved to process and store large amounts of information of many different types. Much of that information deals with laws of reality, such as the effect of gravity. Yet we love to imagine worlds where these laws are broken and people are free to fly, live forever, or communicate telepathically with fish like Aquaman. There is a reason that DC Comics has made so much money. According to Steven Mithen, imagination is the process of swapping around existing information in our brains to create unrealistic ideas (6). He claims that because our brains did not evolve to deal with information we know to be false, we need to express these ideas creatively for them to make sense to us. We do this though art, poetry, and stories. All ideas need sophisticated language to allow us to think about them and express them. Ideas can build upon existing ideas created by other people. Language is fluid; one person may express one idea and another may elaborate on it. Simple communication does not allow for this type of expression, but language does. Language could not have evolved just for this purpose; we were lucky monsters that developed this remarkable skill by chance, forever setting our species apart from all others. Language enables us to share the thoughts and ideas that make us creative individuals, something no other species can do.
There is no doubt that language is a distinctly human gift. Though communication exists in many forms in the animal kingdom, only humans have developed the skill to exchange ideas about things that are not a part of reality, but of our minds. We can create our own ideas and express them to others so that they may add their own thoughts. Since no other animal has this capability, it seems that language developed as a chance side-effect during the evolution of the human brain. It is certainly not necessary to survival, but it is what makes us human.
1. http://www.gps.caltech.edu/~rkopp/collegepapers/chimps.htmlcsa, “Chimpanzee communications and the evolution of human language” by Bob Kopp
2. http://www.csa.com/discoveryguides/lang/overview.php, “Language Origins” by Christopher Croom
3. http://www.washingtonpost.com/wp-srv/style/longterm/books/chap1/symbolicspecies.htm, “The Symbolic Species: The Co-Evolution of Language and the Brain” by Terrence W. Deacon
4. http://mypage.iu.edu/~shetter/miniatures/childsign.htm, “Reinventing Language?”
5. http://mypage.iu.edu/~shetter/miniatures/evolve.htm, “The Evolution of Language”
6. http://muse.jhu.edu/journals/substance/v030/30.1mithen.html, “The Evolution of Imagination: An Archaeological Perspective” by Steven J. Mithen
7. http://www.sciencemag.org/cgi/content/full/305/5691/1720, “Signposts to the Essence of Language” by Michael Siegal
8. http://www.news-medical.net/?id=4883, “Nicaraguan deaf children create a new sign language entirely their own”