Steven Pinker -- How the Mind Works - Hampshire High Italian ...

112 HOW THE MIND WORKSCONNECTOPLASMWhere do the rules and representations in mentalese leave off and theneural networks begin? Most cognitive scientists agree on the extremes.At the highest levels of cognition, where we consciously plod throughsteps and invoke rules we learned in school or discovered ourselves, themind is something like a production system, with symbolic inscriptionsin memory and demons that carry out procedures. At a lower level, theinscriptions and rules are implemented in something like neural networks,which respond to familiar patterns and associate them with otherpatterns. But the boundary is in dispute. Do simple neural networks handlethe bulk of everyday thought, leaving only the products of booklearningto be handled by explicit rules and propositions? Or are thenetworks more like building blocks that aren't humanly smart until theyare assembled into structured representations and programs?A school called connectionism, led by the psychologists David Rumelhartand James McClelland, argues that simple networks by themselves canaccount for most of human intelligence. In its extreme form, connectionismsays that the mind is one big hidden-layer back-propagation network, or perhapsa battery of similar or identical ones, and intelligence emerges when atrainer, the environment, tunes the connection weights. The only reason thathumans are smarter than rats is that our networks have more hidden layersbetween stimulus and response and we live in an environment of otherhumans who serve as network trainers. Rules and symbols might be usefulas a rough-and-ready approximation to what is happening in a network for apsychologist who can't keep track of the millions of streams of activationflowing through the connections, but they are no more than that.The other view—which I favor—is that those neural networks alonecannot do the job. It is the structuring of networks into programs for manipulatingsymbols that explains much of human intelligence. In particular,symbol manipulation underlies human language and the parts of reasoningthat interact with it. That's not all of cognition, but it's a lot of it; it's everythingwe can talk about to ourselves and others. In my day job as a psycholinguistI have gathered evidence that even the simplest of talents thatgo into speaking English, such as forming the past tense of verbs (walk intowalked, come into came), is too computationally sophisticated to be handled