GO FISH

Dick Pountain/14 March 1998/Idealog 44

Picture a warm, clear tropical sea. Over the coral reef swims a large shoal of small silvery fish, swooping this way and that as if they were a single organism. Maybe they are auditioning for a part in an Andersen Consulting ad. A school of barracuda approaches from the right, swimming 40 feet nearer to the surface. The mere shadow of one barracuda falls across a few little fishes at the righthand edge of the shoal, and the whole shoal veers sharp left and accelerates away out of our vision.

The little fishy brain that coordinated this mundane escape scenario is a remarkable enough instrument, and it differs not that much from the deepest and 'oldest' (in the evolutionary sense) parts of our own brain, but nothing it does could be reasonably be described by the word 'think'. That rightmost little fish didn't think "Yikes, a barracuda, I must flee". It just turned and ran, almost as automatically as that pressure pad opens the doors to Sainsbury's for you, because part of its brain had been honed by generations of evolution to recognise the shape of a barracuda's shadow and haul ass. The rest of the shoal maybe didn't see the barracuda at all - they just saw their right-hand neighbour coming nearer and automatically turn away, so propagating the avoiding motion as a rapid wave through the whole shoal. Fish brains can do lots of other stuff too, like recognising other predators, finding food and potential mates, while all the time coordinating the many muscles that make it swim. It's perfectly honed to handle the four F's - three of which are Feeding, Fighting and Fleeing, and all of which we humans do much as he fishes do (the sex life of the salmon being excepted).

It's easy enough to write a little Pascal program to emulate such shoaling behaviour via a simple proximity rule - and even easier to kid yourself that it tells you anything much about how a fish's brain works. Research into analog neural networks is beginning to grasp at the principles involved, but imitating the performance in silicon is not easy at all. Given a task like dividing 134 by 23, a digital silicon CPU will outperform you or I by several orders of magnitude, but when it comes to riding a bicycle silicon emulations still have a long way to go (let alone balancing a pencil on your finger while softly whistling 'Yankee Doodle', watching television and smelling whether your dinner is burning).

The complete evolutionary path that leads to the human brain may never be wholly unravelled  but it's possible to postulate some of the milestones. One of our primate ancestors, for whatever reason, found that sound processing was a useful survival skill (because it carries well through forest canopies, or across grassy savanna - who knows?). The brain areas that controlled hearing and vocalising grew, enabling a larger repertoire of sounds, though These sounds were still simple signals, firmly attached to specific objects or event: let's say that 'eek' always meant 'look out an eagle is coming', and 'awk' meant 'this tastes good'.

The first crucial milestone was when these signals came loose from the objects they referred to - the brain became an exquisitely sensitive device for parsing sound streams into phonemes and distinguishing one utterance from another, so that the creatures could invent new names and attach them to things, rather than relying on a fixed inherited repertoire, and the variety of different human languages became possible. The next milestone was the appearance of the voice in the head. To use an abstract language, you need to assemble and edit new utterances, and that requires you to hear them in your head, as if they'd been spoken. Finally they really could think "Yikes, a barracuda" - or even "Je pense, donc j'existe" - culture became possible, and with it technology to tame nature. 

Human existence became (at least partially) uncoupled from physical evolution, since you don't need to evolve your legs too much once you're smart enough to invent the hunting rifle. The voice in your head also means that you can compute in a wholly different way, mediated by language. The reason it takes you longer to divide 134 by 23 than it takes a Pentium is that you are probably (unless you are an autistic savant) doing it by school-taught long division, using the voice in your head - you're thinking a symbolic simulation of a computer. Which is people are so easily deluded that their brain might be a digital computer. Your old 'four Fs' brain' performs the equivalent of scores of complex trigonometric calculations in a fraction of a second, every time you reach to catch a ball, but that ability has no direct interface to your conscious mind.

For a decade now it's been fashionable to deride the work of Sigmund Freud - in part because his teachings have been grossly misused as an instrument of terror by the 'recovered memory' movement - but the facts of brain physiology tell us that he was surely right about the existence of the Unconscious. It's just the collective working of the old brain layer breaking through into the internal voice via various channels. Here's a different computer analogy; the Unconscious is somewhat like the megabytes of OS routines  working away invisibly under the surface every time your PC's display changes. Freud's 'ego/id' terminology was a kludge he invented because there were no words for these inherently unspeakable things, and he said that in future neuro-physiologists would replace them with more scientific terms. Very soon they will.