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If overstimulation at the sensory level increases the distortion with which we perceive reality, cognitive overstimulation interferes with our ability to "think." While some human responses to novelty are involuntary, others are preceded by conscious thought, and this depends upon our ability to absorb, manipulate, evaluate and retain information.
Rational behavior, in particular, depends upon a ceaseless flow of data from the environment. It depends upon the power of the individual to predict, with at least fair success, the outcome of his own actions. To do this, he must be able to predict how the environment will respond to his acts. Sanity, itself, thus hinges on man's ability to predict his immediate, personal future on the basis of information fed him by the environment.
When the individual is plunged into a fast and irregularly changing situation, or a novelty-loaded context, however, his predictive accuracy plummets. He can no longer make the reasonably correct assessments on which rational behavior is dependent.
To compensate for this, to bring his accuracy up to the normal level again, he must scoop up and process far more information than before. And he must do this at extremely high rates of speed. In short, the more rapidly changing and novel the environment, the more information the individual needs to process in order to make effective, rational decisions.
Yet just as there are limits on how much sensory input we can accept, there are in-built constraints on our ability to process information. In the words of psychologist George A. Miller of Rockefeller University, there are "severe limitations on the amount of information that we are able to receive, process, and remember." By classifying information, by abstracting and "coding" it in various ways, we manage to stretch these limits, yet ample evidence demonstrates that our capabilities are finite.
To discover these outer limits, psychologists and communications theorists have set about testing what they call the "cha
Information has been defined technically and measured in terms of units called "bits." (A bit is the amount of information needed to make a decision between two equally likely alternatives. The number of bits needed increases by one as the number of such alternatives doubles.) By now, experiments have established rates for the processing involved in a wide variety of tasks from reading, typing, and playing the piano to manipulating dials or doing mental arithmetic. And while researchers differ as to the exact figures, they strongly agree on two basic principles: first, that man has limited capacity; and second, that overloading the system leads to serious breakdown of performance.
Imagine, for example, an assembly line worker in a factory making childrens' blocks. His job is to press a button each time a red block passes in front of him on the conveyor belt. So long as the belt moves at a reasonable speed, he will have little difficulty. His performance will approach 100 percent accuracy. We know that if the pace is too slow, his mind will wander, and his performance will deteriorate. We also know that if the belt moves too fast, he will falter, miss, grow confused and uncoordinated. He is likely to become tense and irritable. He may even take a swat at the machine out of pure frustration. Ultimately, he will give up trying to keep pace.
Here the information demands are simple, but picture a more complex task. Now the blocks streaming down the line are of many different colors. His instructions are to press the button only when a certain color pattern appears – a yellow block, say, followed by two reds and a green. In this task, he must take in and process far more information before he can decide whether or not to hit the button. All other things being equal, he will have even greater difficulty keeping up as the pace of the line accelerates.
In a still more demanding task, we not only force the worker to process a lot of data before deciding whether to hit the button, but we then force him to decide which of several buttons to press. We can also vary the number of times each button must be pressed. Now his instructions might read: For color pattern yellow-red-red-green, hit button number two once; for pattern green-blue-yellow-green, hit button number six three times; and so forth. Such tasks require the worker to process a large amount of data in order to carry out his task. Speeding up the conveyor now will destroy his accuracy even more rapidly.
Experiments like these have been built up to dismaying degrees of complexity. Tests have involved flashing lights, musical tones, letters, symbols, spoken words, and a wide array of other stimuli. And subjects, asked to drum fingertips, speak phrases, solve puzzles, and perform an assortment of other tasks, have been reduced to blithering ineptitude. The results unequivocally show that no matter what the task, there is a speed above which it ca
Clearly, these findings can help us understand certain forms of psychological upset. Managers plagued by demands for rapid, incessant and complex decisions; pupils deluged with facts and hit with repeated tests; housewives confronted with squalling children, jangling telephones, broken washing machines, the wail of rock and roll from the teenager's living room and the whine of the television set in the parlor – may well find their ability to think and act clearly impaired by the waves of information crashing into their senses. It is more than possible that some of the symptoms noted among battle-stressed soldiers, disaster victims, and culture shocked travelers are related to this kind of information overload.
One of the men who has pioneered in information studies, Dr. James G. Miller, director of the Mental Health Research Institute at the University of Michigan, states flatly that "Glutting a person with more information than he can process may ... lead to disturbance." He suggests, in fact, that information overload may be related to various forms of mental illness.
One of the striking features of schizophrenia, for example, is "incorrect associative response." Ideas and words that ought to be linked in the subject's mind are not, and vice versa. The schizophrenic tends to think in arbitrary or highly personalized categories. Confronted with a set of blocks of various kinds – triangles, cubes, cones, etc. – the normal person is likely to categorize them in terms of geometric shape. The schizophrenic asked to classify them is just as likely to say "They are all soldiers" or "They all make me feel sad."
In the volume Disorders of Communication, Miller describes experiments using word association tests to compare normals and schizophrenics. Normal subjects were divided into two groups, and asked to associate various words with other words or concepts. One group worked at its own pace. The other worked under time pressure – i.e., under conditions of rapid information input. The time-pressed subjects came up with responses more like those of schizophrenics than of self-paced normals.
Similar experiments conducted by psychologists G. Usdansky and L. J. Chapman made possible a more refined analysis of the types of errors made by subjects working under forced-pace, high information-input rates. They, too, concluded that increasing the speed of response brought out a pattern of errors among normals that is peculiarly characteristic of schizophrenics.