Language and the Emergence of Human Cognition
IF THERE IS ONE single aspect of human mental function that is more closely tied up with symbolic processes than any other, it is surely our use of language. Language is, indeed, the ultimate symbolic mental function, and it is virtually impossible to conceive of thought as we know it in its absence. For words, it is fair to say, function as the units of human thought, at least as we are aware of it. They are certainly the medium by which we explain our thoughts to one another and, as incomparably social creatures, seek to influence what is going on in one anothers brains. Thus, if we are seeking a single cultural releasing factor that opened the way to symbolic cognition, the invention of language is the most obvious candidate. Indeed, it is perhaps the only plausible one that it has so far proved possible to identify. What might have happened? Here we have to return to notions of exaptation, for language is a unique aptitude that doesnt seem to have emerged from apelike protolanguage and certainly did not do so directly. Still, it has been argued that since the general ability to acquire language appears to be deeply and universally embedded in the human psyche, this ability must be hardwired into every healthy human brain, where it resides as a result of normal Darwinian processes of adaptation by natural selection.
It is certainly true that language is not reinvented in every generation but is rather re-expressed, as every child learns his native tongue(s) as an ordinary, if astonishing, part of the process of growing up. There is, in other words, no denying the existence in the human mind of a language instinct. What we need to explain, however, is not only how that innate instinct was acquired but also how it made such a rapid and unprecedented appearance.
As weve seen, natural selection is not a creative force and can propel nothing into existence by itself. Rather it can only capitalize on what is already there. In a sense, this makes things easier for us since, as far as we can tell, in the emergence of symbolic thought there is no evidence of the kind of slow trend that would be expected under Darwinian selection. What must have happened, instead, is that after a long--and poorly understood--period of erratic brain expansion and reorganization in the human lineage, something occurred that set the stage for language acquisition. This innovation would have depended on the phenomenon of emergence, whereby a chance combination of preexisting elements results in something totally unexpected. The classic example of an emergent quality is water, most of whose remarkable characteristics are entirely unpredicted by those of its constituents, hydrogen and oxygen. Nonetheless, the combination of these ingredients gives rise to something entirely new, and expected only in hindsight. Together with exaptation, emergence provides a powerful mechanism in the evolutionary process, and it truly is a driving force, propelling innovation in new directions.
In the case of linguistic potential, with its innate presence among all humans today, we have to suppose that initially a neural change occurred in some population of the human lineage. This change was presumably rather minor in genetic terms and probably had nothing whatever to do with adaptation in the classical sense. Since during early childhood development the brain rewires itself through the creation of specific pathways from undifferentiated masses of neuronal connections, it is even possible that this event was an epigenetic rather than a genetic one, dependent on developmental stimuli. Whatever the case, it certainly seems to have made no mark on the fossil record, although ultimately its impact on the archaeological traces of the Cro-Magnons and their successors was enormous. Just as the keystone of an arch is a trivial part of the structure, yet is essential to the integrity of the whole, this innovation (whatever it may have been, and we are very far from understanding that) was the final physical element that needed to be in place to make possible language and symbolic thought--and all that has flowed from them, with such fateful consequences for the world. Once it was there, of course, the potential it embodied could lie fallow, simply doing no harm, until released by a cultural stimulus in one particular population. Almost certainly, though its hard to prove, this stimulus was the invention of language. Everyone today has language, which by itself suggests that it was a highly advantageous acquisition. And if it is as advantageous as we would wish to believe, it is hardly surprising that language and its associated symbolic behavioral patterns were subsequently able to spread rapidly among human populations worldwide.