In this way, new knowledge alters old. The mass media instantly and persuasively disseminate new images, and ordinary individuals, seeking help in coping with an ever more complex social environment, attempt to keep up. At the same time, events – as distinct from research as such – also batter our old image structures. Racing swiftly past our attention screen, they wash out old images and generate new ones. After the freedom rides and the riots in black ghettos only the pathological could hang on to the long-cherished notion that blacks are "happy children" content with their poverty. After the Israeli blitz victory over the Arabs in 1967, how many still cling to the image of the Jew as a cheek-turning pacifist or a battlefield coward?
In education, in politics, in economic theory, in medicine, in international affairs, wave after wave of new images penetrate our defenses, shake up our mental models of reality. The result of this image bombardment is the accelerated decay of old images, a faster intellectual through-put, and a new, profound sense of the impermanence of knowledge, itself.
This impermanence is reflected in society in many subtle ways. A single dramatic example is the impact of the knowledge explosion on that classic knowledge-container, the book.
As knowledge has become more plentiful and less permanent, we have witnessed the virtual disappearance of the solid old durable leather binding, replaced at first by cloth and later by paper covers. The book itself, like much of the information it holds, has become more transient.
A decade ago, communications systems designer Sol Cornberg, a radical prophet in the field of library technology, declared that reading would soon cease to be a primary form of information intake. "Reading and writing," he suggested, "will become obsolete skills." (Ironically, Mr. Cornberg's wife is a novelist.)
Whether or not he is correct, one fact is plain: the incredible expansion of knowledge implies that each book (alas, this one included) contains a progressively smaller fraction of all that is known. And the paperback revolution, by making inexpensive editions available everywhere, lessens the scarcity value of the book at precisely the very moment that the increasingly rapid obsolescence of knowledge lessens its longterm informational value. Thus, in the United States a paperback appears simultaneously on more than 100,000 newsstands, only to be swept away by another tidal wave of publications delivered a mere thirty days later. The book thus approaches the transience of the monthly magazine. Indeed, many books are no more than "one-shot" magazines.
At the same time, the public's span of interest in a book – even a very popular book – is shrinking. Thus, for example, the life span of best sellers on The New York Times list is rapidly declining. There are marked irregularities from year to year, and some books manage to buck the tide. Nevertheless, if we examine the first four years for which full data on the subject is available, 1953-1956, and compare this with a similar period one decade later, 1963-1966, we find that the average best seller in the earlier period remained on the list a full 18.8 weeks. A decade later this had shrunk to 15.7 weeks. Within a ten-year-period, the life expectancy of the average best seller had shrunk by nearly one-sixth.
We can understand such trends only if we grasp the elemental underlying truth. We are witnessing an historic process that will inevitably change man's psyche. For across the board, from cosmetics to cosmology, from Twiggy-type trivia to the triumphant facts of technology, our inner images of reality, responding to the acceleration of change outside ourselves, are becoming shorter-lived, more temporary. We are creating and using up ideas and images at a faster and faster pace. Knowledge, like people, places, things and organizational forms, is becoming disposable.
If our inner images of reality appear to be turning over more and more rapidly, one reason may well be an increase in the rate at which image-laden messages are being hurled at our senses. Little effort has been made to investigate this scientifically, but there is evidence that we are increasing the exposure of the individual to image-bearing stimuli.
To understand why, we need first to examine the basic sources of imagery. Where do the thousands of images filed in our mental model come from? The external environment showers stimuli upon us. Signals originating outside ourselves – sound waves, light, etc. – strike our sensory organs. Once perceived, these signals are converted, through a still mysterious process, into symbols of reality, into images.
These incoming signals are of several types. Some might be called uncoded. Thus, for example, a man walks along a street and notices a leaf whipped along the sidewalk by the wind. He perceives this event through his sensory apparatus. He hears a rustling sound. He sees movement and greenness. He feels the wind. From these sensory perceptions he somehow forms a mental image. We can refer to these sensory signals as a message. But the message was not, in any ordinary sense of the term, man-made. It was not designed by anyone to communicate anything, and the man's understanding of it does not depend directly on a social code – a set of socially agreed-upon signs and definitions. We are all surrounded by and participate in such events. When they occur within range of our senses, we may pick up uncoded messages from them and convert these messages into mental images. In fact, some proportion of the images in every individual's mental model are derived from such uncoded messages.
But we also receive coded messages from outside ourselves. Coded messages are any which depend upon social convention for their meaning. All languages, whether based on words or gestures, drumbeats or dancesteps, hieroglyphs, pictographs or the arrangement of knots in a string, are codes. All messages conveyed by means of such languages are coded. We may speculate with some safety that as societies have grown larger and more complex, proliferating codes for the transmission of images from person to person, the ratio of uncoded messages received by the ordinary person has declined in favor of coded messages. We may guess, in other words, that today more of our imagery derives from man-made messages than from personal observation of raw, "uncoded" events.
Furthermore, we can discern a subtle but significant shift in the type of coded messages as well. For the illiterate villager in an agricultural society of the past, most of the incoming messages were what might be called casual or "do-it-yourself" communications. The peasant might engage in ordinary household conversation, banter, cracker-barrel or tavern talk, griping, complaining, boasting, baby talk, (and, in the same sense, animal talk), etc. This determined the nature of most of the coded messages he received, and one characteristic of this sort of communication is its loose, unstructured, garrulous or unedited quality.
Compare this message input with the kind of coded messages received by the ordinary citizen of the present-day industrial society. In addition to all of the above, he also receives messages – mainly from the mass media – that have been artfully fashioned by communications experts. He listens to the news; he watches carefully scripted plays, telecasts, movies; he hears much more music (a highly disciplined form of communication); he hears frequent speeches. Above all, he does something his peasant ancestor could not do: He reads – thousands of words every day, all of them carefully edited in advance.
The industrial revolution, bringing with it the enormous elaboration of the mass media, thus alters radically the nature of the messages received by the ordinary individual. In addition to receiving uncoded messages from the environment, and coded but casual messages from the people around him, the individual now begins to receive a growing number of coded but pre-engineered messages as well.