Number of words: 896<\/p>\n\n\n\n
Unfortunately, the nervous system has definite limits on how much information it can process at any given time. There are just so many \u201cevents\u201d that can appear in consciousness and be recognized and handled appropriately before they begin to crowd each other out. Walking across a room while chewing gum at the same time is not too difficult, even though some statesmen have been alleged to be unable to do it; but, in fact, there is not that much more that can be done concurrently. Thoughts have to follow each other, or they get jumbled. While we are thinking about a problem we cannot truly experience either happiness or sadness. We cannot run, sing, and balance the checkbook simultaneously, because each one of these activities exhausts most of our capacity for attention.<\/p>\n\n\n\n
At this point in our scientific knowledge we are on the verge of being able to estimate how much information the central nervous system is capable of processing. It seems we can manage at most seven bits of information\u2014such as differentiated sounds, or visual stimuli, or recognizable nuances of emotion or thought\u2014at any one time, and that the shortest time it takes to discriminate between one set of bits and another is about 1\/18 of a second. By using these figures one concludes that it is possible to process at most 126 bits of information per second, or 7,560 per minute, or almost half a million per hour. Over a lifetime of seventy years, and counting sixteen hours of waking time each day, this amounts to about 185 billion bits of information. It is out of this total that everything in our life must come\u2014every thought, memory, feeling, or action. It seems like a huge amount, but in reality it does not go that far.<\/p>\n\n\n\n
The limitation of consciousness is demonstrated by the fact that to understand what another person is saying we must process 40 bits of information each second. If we assume the upper limit of our capacity to be 126 bits per second, it follows that to understand what three people are saying simultaneously is theoretically possible, but only by managing to keep out of consciousness every other thought or sensation. We couldn\u2019t, for instance, be aware of the speakers\u2019 expressions, nor could we wonder about why they are saying what they are saying, or notice what they are wearing.<\/p>\n\n\n\n
Of course, these figures are only suggestive at this point in our knowledge of the way the mind works. It could be argued justifiably that they either underestimate or overestimate the capacity of the mind to process information. The optimists claim that through the course of evolution the nervous system has become adept at \u201cchunking\u201d bits of information so that processing capacity is constantly expanded. Simple functions like adding a column of numbers or driving a car grow to be automated, leaving the mind free to deal with more data. We also learn how to compress and streamline information through symbolic means\u2014language, math, abstract concepts, and stylized narratives. Each biblical parable, for instance, tries to encode the hard-won experience of many individuals over unknown eons of time. Consciousness, the optimists argue, is an \u201copen system\u201d; in effect, it is infinitely expandable, and there is no need to take its limitations into account.<\/p>\n\n\n\n
But the ability to compress stimuli does not help as much as one might expect. The requirements of life still dictate that we spend about 8 percent of waking time eating, and almost the same amount taking care of personal bodily needs such as washing, dressing, shaving, and going to the bathroom. These two activities alone take up 15 percent of consciousness, and while engaged in them we can\u2019t do much else that requires serious concentration. But even when there is nothing else pressing occupying their minds, most people fall far below the peak capacity for processing information. In the roughly one-third of the day that is free of obligations, in their precious \u201cleisure\u201d time, most people in fact seem to use their minds as little as possible. The largest part of free time\u2014almost half of it for American adults\u2014is spent in front of the television set. The plots and characters of the popular shows are so repetitive that although watching TV requires the processing of visual images, very little else in the way of memory, thinking, or volition is required. Not surprisingly, people report some of the lowest levels of concentration, use of skills, clarity of thought, and feelings of potency when watching television. The other leisure activities people usually do at home are only a little more demanding. Reading most newspapers and magazines, talking to other people, and gazing out the window also involve processing very little new information, and thus require little concentration.<\/p>\n\n\n\n
So the 185 billion events to be enjoyed over our mortal days might be either an overestimate or an underestimate. If we consider the amount of data the brain could theoretically process, the number might be too low; but if we look at how people actually use their minds, it is definitely much too high. In any case, an individual can experience only so much. Therefore, the information we allow into consciousness becomes extremely important; it is, in fact, what determines the content and the quality of life. <\/p>\n\n\n\n