NONSENSE AND NONSENSIBILITY

Dick Pountain/Idealog 264/06 July 2016 10:38

When Joshua Brown's Tesla Model S smashed right through a trailer-truck at full speed, back in May in Florida, he paid a terrible price for a delusion that, while it may have arisen first in Silicon Valley, is now rapidly spreading among the world's more credulous techno-optimists. The delusion is that AI is now sufficiently advanced for it to be permitted to drive motor vehicles on public roads without human intervention. It's a delusion I don't suffer from, not because I'm smarter than everyone else, but simply because I live in Central London and ride a Vespa. Here, the thought that any combination of algorithms and sensors short of a full-scale human brain could possibly cope with the torrent of dangerous contigencies one faces is too ludicrous to entertain for even a second - but on long, straight American freeways it could be entertained for a while, to Joshua's awful misfortune.

The theory behind driverless vehicles is superficially plausible, and fits well with current economic orthodoxies: human beings are fallible, distractable creatures whereas computers are Spock-like, unflappable and wholly rational entities that will drive us more safely and hence save a lot of the colossal sums that road accidents cost each year. And perhaps more significant still, they offer to ordinary mortals one great privilege of the super-rich, namely to be driven about effortlessly by a chauffeur.

The theory is however deeply flawed because it inherits the principal delusion of almost all current AI research, namely that human intelligence is based mostly on reason, and that emotion is an error condition to be eradicated as far as possible. This kind of rationalism arises quite naturally in the computer business, because it tends to select mathematically-oriented, nerdish character types (like me) and because computers are so spectacularly good, and billions of times faster than us, at logical operations. It is however totally refuted by recent findings in both cognitive science and neuroscience. From the former, best expressed by Nobel laureate Daniel Kahneman, we learn that the human mind mostly operates via quick, lazy, often systematically-wrong assumptions, and it has to be forced, kicking and screaming, to apply reason to any problem. Despite this we cope fairly well and the world goes on. When we do apply reason it as often as not achieves the opposite of our intention, because of the sheer complexity of the environment and our lack of knowledge of all its boundary conditions.

That makes me a crazy irrationalist who believes we're powerless to predict anything and despises scientific truth then? On the contrary. Neuroscience offers explanations for Kahneman's findings (which were themselves the result of decades of rigorous experiment). Our mental processes are indeed split, not between logic and emotion as hippy gurus once had it, but between novelty and habit. Serious new problems can indeed invoke reason, perhaps even with recourse to written science, but when a problem recurs often enough we eventually store an heuristic approximation of its solution as "habit" which doesn't require fresh thought every time. It's like a stored database procedure, a powerful kind of time-saving compression without which civilisation could never have arisen. Throwing a javelin, riding a horse, driving a car, greeting a colleague, all habits, all fit for purpose most of the time.

Affective neuroscience, by studying the limbic system, seat of the emotions, throws more light still. Properly understood, emotions are automatic brain subsystems which evolved to deal rapidly with external threats and opportunities by modifying our nervous system and body chemistry (think fight-and-flight, mating, bonding). What we call emotions are better called feelings, our perceptions of these bodily changes rather than the chemical processes that caused them. Evidence is emerging, from the work of Antonio Damasio and others, that our brains tag each memory they deposit with the emotional state prevailing at the time. Memories aren't neutral but have "good" or "bad" labels, which get weighed in the frontal cortex whenever memories are recalled to assist in solving a new problem. In other words, reason and emotion are completely, inextricably entangled at a physiological level. This mechanism is deeply involved in learning (reward and punishment, dopamine and adrenalin), and even perception itself. We don't see the plain, unvarnished world but rather a continually-updated model in our brain that attaches values to every object and area we encounter.

This is what makes me balk before squeezing my Vespa between that particular dump-truck and that particular double-decker bus, and what would normally tell you not to watch Harry Potter while travelling at full speed on the freeway. But it's something no current AI system can duplicate and perhaps never will: that would involve driverless vehicles being trained for economically-unviable periods using value-aware memory systems that don't yet exist.