Each of the three major mental modules that had developed in the progression from primates to hominids to humans (visual/spatial, social, and natural history) were fairly straightforward pattern-recognizing systems. Very elaborate pattern-recognizing systems, to be sure, but still within the basic structure of what neurons were designed to handle. Recognizing texture patterns, performing stereoscopic calculations, figuring out who’s your friend and who’s your enemy, and reading tracks and scat are all pattern-recognition tasks.
But language is different. Language is spoken and heard in serial fashion -- one word after another, and that sequence of words constitutes a larger structure comprising a meaningful expression. Thus, language is at its core a sequential system, requiring sequential reasoning on a massive scale to comprehend. Remember from the discussion of Sequentialism that this kind of processing requires many more neurons than the normal pattern-recognition stuff that neurons are good at. Neurons were designed and developed over 400 million years to process patterns, and only in the last 100 million years have they been called upon to perform sequential processing tasks -- and even then, the processing requirements were light. It is only in the last few hundred thousand years that humans have been doing enormous amounts of sequential processing, and neurons have not had enough time to specialize for this kind of processing. This is why language processing demands so much brain tissue, and why language has not arisen in other species. It’s a huge step from single animal calls to sequenced language.
So humans developed a major new chunk of brain devoted to linguistic processing. Now, it’s important to realize a major distinction between the brain and computer systems. The latter are all neatly modularized, with RAM over here and video display over there, everything in its proper little compartment. You can rip out a hard drive and stuff in another, and the computer system works just as well. Not so the brain; everything’s wired together and tightly interconnected. Language processing is a major mental module, but that doesn’t mean that we have one module that thinks for us and then ships its output to the language module for output. Input from the ear doesn’t go into a little black box labelled “language processing” for interpretation, with the results being shipped off to some kind of “Central Processing Unit” elsewhere in the brain. No, the linguistic processing is closely integrating into the thinking process – or at least a goodly part of it. Our various mental modules aren’t “data processors” – they are thinking machines. Each one is specialized to think about a particular class of problem, but they’re all hooked together cooperatively. There’s no cleavage plane between the thinking of a thought and the expression of the thought.
This is not to say that linguistic expression constitutes the entirety of thinking. The other mental modules chip in their two cents’ worth, too. When we think about something, the visual/spatial module plays its role, the social reasoning module chips in, the natural history module renders its judgement, and the linguistic module weighs in with its opinion, too. Meanwhile, a dozen minor mental modules are probably also squeaking their own ideas. That’s why thinking about something can be such a confusing process – there are so many voices, so many opinions inside your head. In the good old days before language, the whole system was neat and clean: spatial problems went to the spatial reasoning module, social relationship problems went to the social reasoning module, and so forth. Each module had its place and answered its own problems.
But verbal reasoning is special in an important way: it extends its tentacles into every nook and cranny of the mind. You could have an Einstein-level natural history mental module, but if you couldn’t translate your brilliant ideas about the environment into words, you couldn’t communicate them to others, and they wouldn’t be very useful. Thus, every conceptual atom in the human mind required its own little tag for the verbal reasoning system. That tag is what we today call a word. Thus, the whole brain was quickly cluttered up with all these little tags, which in turn were connected to a chunk of tissue on the left side of the brain, where some of the detailed processing took place.
In so doing, however, the linguistic processing mental module, in effect, connected all of the other mental modules into a kind of brain Internet. Those modules had arisen separately, were used for completely different problems, and so went about their business in blithe disregard for each other. But the linguistic module, since it had connections into each separate module, in effect tied them all together. At first, this didn’t pose any problem, but as the language-Internet grew more important in the mind of the human, interactions among the modules were certain to arise.
To make matters trickier still, each problem we encounter is best tackled with a different mix of weightings of the different mental modules. When the car won’t start, you’ll likely use a lot of your visual/spatial module to visualize the component that is failing, but you’ll also make some use of your natural history module (updated for modern times): “Ungawa. Me no smell gasoline fumes, so engine not flooded. Engine sounded like it turned over fast, so battery OK. Me look under car for automobile scat, er, oil leak – no sign.” If this fails, you might resort to your social reasoning module: “Please, please, if you just start, I promise I’ll change your spark plugs as soon as I get home.”
And of course, we all have different strengths and weaknesses in the various mental modules. My wife, whose natural history module with respect to cars is rather weak, once reacted to our old truck’s refusal to start by beating it with a mallet. The act makes no sense to a mechanic with a highly developed natural history module for automobile mechanics, but it was perfectly good social reasoning.
So verbal reasoning is just one more form of thinking in our mental module toolkit. But it is utterly different from all the other modules in two respects: first, it is fundamentally sequential in nature, and second, it’s connected to every other module. Where the other modules give us ways to recognize and respond to particular patterns, the verbal reasoning module provides us with a way to think about sequences – and that, it turns out, made all the difference. Language was so useful that it, in effect, staged a coup d’etat and took over the brain.