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See also: Evolutionary psychology -- Categorization and concept formation
Consequently, and obviously, in a discussion of language (especially, but as with almost anything else, of course) it helps to be clear on what we are "talking" about.
One way to describe it is to say that language consists of "words" and "rules" -- vocabulary and grammar, more formally. That specifies it pretty well intuitively, provided we allow that occasionally "words" need not be limited to phonetic objects (or their equivalents in a "written" form) -- as in sign language, for example.
But there are other ways to describe language. For instance, we can try to talk about language in functional terms, i. e., how it is used. To begin with, there are things and events in the "real" world. From these, our minds form "concepts" -- representations in our minds of the external things and events. (Admittedly, we don't understand very well how this representation is actually implemented in our brains.) Although incontrovertible evidence is hard to come by, it is likely that we share with many higher animals the ability to form concepts.
Finally, then, we have language, which provides convenient "handles" for performing mental operations with concepts and for communicating about them to others. It is in this that humans seem to do what no other species does.
It is true that animals of various other species have vocal behavior (or equivalents in terms of gestures, postures, etc.) Notably, there are the songs of birds and whales, and the barking, howling, or growling of canines. We would be justified in calling such things language only if (1) there were grammar-like rules which governed their use and (2) the vocal (or whatever) behavior could be analyzed into elements analogous to words, which in turn correspond to concepts.
We may some day find good evidence of behavior in other species that meets these criteria. If so, then we can add such examples. What about the dances which honey bees perform to tell other bees in the hive where a new source of nectar has been found? Can we suppose that an insect brain has enough complexity to form "concepts"? Is there a "grammar" to this bee dance language which is anything like the grammar of human language? Neither seems likely. So, in our present state of knowledge, human language seems to be something almost unique in the natural world, and that's what we will focus on.
On the assumption that language is innate, i. e., there is a significant biological substrate for the ability to understand and use language, then the question is how this came about. That is, how did it "evolve".
Note that the answer to this question will depend on how we think of evolution in general. Evolution has two parts to it: variation and selection. Variation is guaranteed through at least two mechanisms: the shuffling of genes which occurs in sexual reproduction and the alterations of genes by mutations.
Selection is something a little harder to pin down. There is always an element of randomness (which is also implicit in variation). It is always conceivable that chance events played a big role in making the linguistic skills of modern humans what they are and working the way they do. For instance, there might, in the distant past, have been a population of early humans in which langauge worked significantly differently from what we are familiar with -- but that population was wiped out by some natural disaster, or simply became extinct. Chance events like this are more a matter of history rather than science. That is, they could have happened, but not on account of general rules or "laws".
Chance events, by definition, cannot be predicted. So, to the extent we seek an explanation that is more "rule-based", we need to look at other types of selection. In evolution, that means primarily (but not exclusively) selection based on "adaptation" and "fitness". How could the biological bases of language usage come about through adaptation?
There are two possibilities. One is that these biological features were selected because they enabled language and that language itself was what supplied the fitness. We'll look more closely at that. But the other possibility is that the biological feature supported some other ability which was adaptive. That is, some parts of the brain developed because they conferred another skill, and this skill was later put to use for language as well. While possible, this sort of explanation is problematical, because it again introduces an element of chance. That is, some feature of the brain which evolved for a different application just happened to be useful for language. "Coincidences" like this are always scientifically suspect. Whenever we have something like this, it's always worth asking whether we can't do better.
"Doing better" means, in this case, showing how language ability is itself adaptive for humans. It isn't too hard to think of ways this might be. In the first place, all hominid species, and most other primates besides, are social rather than solitary. Individuals of such species generally live together in family groups and clans. To the extent that language facilitates social interaction and the success of the clan -- which it pretty clearly does -- it should be selectively favored. But there is a problem here, because this assumes the efficacy of the process of "group selection". This is a controversial notion in evolutionary theory. It's much easier to understand selection working at the level of individuals rather than groups, even when members of the groups are genetically related.
So, how is the possession of language skills -- and in particular, langauge skills which are in excess of the norm -- adaptive for individuals? It isn't too hard to think of possibilities. One feature that's common in both modern humans and most other social mammals is that clans are hierarchically organized. That is, there are a few leaders (or "chiefs") and many followers. Leaders can acquire their status in a variety of ways. In other species, strength and speed -- i. e. physical prowess -- seem to be common factors. This happens in humans too, and probably much more so when life was more physically challenging than in modern society.
But as soon as hominids acquired any language capability at all, greater skill in the use of language could very well have become a factor in acquisition of leadership status. In the modern world, certainly, a way with words is clearly advantageous to politicians, businessmen, media personalities, successful salesmen and anyone else who wants to persuade and/or exercise power over others. It could well have been so also in the paleolithic world. The individuals who were best able to influence the plans of the clan by their use of language around the ancient camp fires should have been natural leaders.
And how does leadership and dominant status in the social hierarchy contribute to "fitness" and reproductive success? Simple -- leaders have always tended to have far more mating opportunities, due to their status, than the rank and file. Need we say more?
Well, actually, we could. Evolutionary theory also recognizes another type of selection -- sexual selection. This is the reason that male peafowl have fancy plumage, and the reason that most other higher animals have characteristics that members of the opposite sex (apparently) find attractive. Language skill, in the form of a good "pickup line" or "sweet talk" could easily have contributed to reproductive success in early humans.
Is the question settled, then? Not really. We are just speculating on how language might have evolved. We don't really have evidence that it actually did happen this way. This is the same difficulty that's common to all evolutionary psychological theories. We weren't around long ago to gather evidence, and this sort of thing leaves little, if any, physical evidence for future generations to evaluate.
It would help if we knew more about the actual brain mechanisms which are involved in the use of language. If we knew more about them, we could better evaluate how likely they are to be heritable. (For instance, we might find that they are more dependent on having the right kind of early training or nutrition than specific hereditary characteristics.) We could also better determine whether these mechanisms were more likely developed originally for purposes other than language.
But before we go on to ask about actual mechanisms, a few final thoughts. Human language, we suppose, was originally vocal. At least, except for the very modern development of written language, we don't know of any cultures, primitive or advanced, which has other than a vocal language (e. g. sign language) amongst individuals capable of speaking and hearing. It seems very likely that the brain mechanisms underlying language must have co-evolved with the vocal mechanisms. Significantly, humans are also the only species with sufficiently complex vocal equipment to support language. And there are indications that Neandertals did not have the same vocal equipment as modern humans.
Another point is that the development of approximately modern language skills seems to be very recent in evolutionary time -- about 100,000 years at most. That is only about 5000 generations -- an astonishingly short time to develop something as complex as langauge. This could indicate either that cultural transmission (which works much more rapidly than biological evolution) has a very big role in language development. Or else that language skill is very strongly selected for. Maybe both.
It's also interesting that 100,000 years ago is about when anatomically modern (Cro-Magnon) humans first appeared. And it's also roughly when the last major eruption of hominids "out of Africa" occurred. Successful rapid mass migrations probably need a high degree of social coordination -- which could be enabled by leadership (and followership) which possessed good language skills. Even though the migration may have advanced only a mile or so per generation on average, the existence of language means that cultural innovations could be communicated over long distances, rather than being confined to a small area which allowed for cultural transmission only from parents to offspring, or at most within one clan.
One other point to ponder is that many of the cultural innovations of the human species, such as art and burial customs, are even more recent -- dating back perhaps only 50,000 years. It's probably significant that (visual) art such as painting developed after -- but not too long after -- language. Art was a means of communication that followed spoken language, but more abstract. It was probably, also, like burial customs, involved in imaginative story telling and myth making.
Copyright © 2002 by Charles Daney, All Rights Reserved