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

136 J HOW THE MIND WORKSby the deliberative, language-using parts of the mind. And this sense,sentience, is the one in which consciousness seems like a miracle.The remainder of the chapter is about consciousness in these last twosenses. First I will look at access, at what kinds of information the differentparts of the mind make available to one another. In this sense of theword, we really are coming to understand consciousness. Interestingthings can be said about how it is implemented in the brain, the role itplays in mental computation, the engineering specs it is designed tomeet (and hence the evolutionary pressures that gave rise to it), and howthose specs explain the main features of consciousness—sensory awareness,focal attention, emotional coloring, and the will. Finally, I will turnto the problem of sentience.Someday, probably sooner rather than later, we will have a fine understandingof what in the brain is responsible for consciousness in thesense of access to information. Francis Crick and Christof Koch, forexample, have set out straightforward criteria for what we should lookfor. Most obviously, information from sensation and memory guidesbehavior only in an awake animal, not an anesthetized one. Thereforesome of the neural bases of access-consciousness can be found in whateverbrain structures act differently when an animal is awake and whenit is in a dreamless sleep or out cold. The lower layers of the cerebral cortexare one candidate for that role. Also, we know that information aboutan object being perceived is scattered across many parts of the cerebralcortex. Therefore information access requires a mechanism that bindstogether geographically separated data. Crick and Koch suggest that synchronizationof neural firing might be one such mechanism, perhapsentrained by loops from the cortex to the thalamus, the cerebrum's centralway-station. They also note that voluntary, planned behavior pequiresactivity in the frontal lobes. Therefore access-consciousness may bedetermined by the anatomy of the fiber tracts running from various partsof the brain to the frontal lobes. Whether or not they are right, they haveshown that the problem can be addressed in the lab.Access-consciousness is also a mere problem, not a mystery, in ourgrasp of the computations carried out by the brain. Recall our uncledetectingproduction system. It has a communal short-term metnory: a