INTRODUCTION . SYSTEMS . THE ROLE OF COMMUNICATION . HUMAN AND NON-HUMAN COMMUNICATION . THE SHANNON/WEAVER MODEL OF COMMUNICATION . CONTENT AND CODE .

HUMAN AND NON-HUMAN COMMUNICATION

Here are a few of the many examples of the communication process that exist in the world that human beings inhabit.

• When a truck picks up a cargo in New Orleans and delivers it to Baltimore, communication has happened.

• When someone steps out onto the beach in Oregon and the salt air touches their nose and the smell of the ocean comes into their mind, communication has happened.

• When two stray cats meet for sex in an alley in Los Angeles, communication has happened.

• When the United States Congress passes, and the President signs, a new law raising the import duty on peanuts, communication has happened.

• When a child having breakfast in Phoenix and reads the back of a cereal box, communication has happened.

• When a whaling ship in the northern Pacific fires a harpoon gun and connects with a surfacing whale, communication has happened.

• When a baby sees its mother's face for the first time, communication has happened.

• When a computer in New York City calls up a computer in Tokyo and transmits a message, communication has happened. 9012

Clearly then, under the definition of communication that was developed in the previous section of this tutorial, the sender and the receiver of messages can be such as whales, cereal boxes, nerve cells, and computers. This leads to the next insight into the nature of communication.

Of course, as human beings ourselves, we are naturally most interested in human communication, and in fact the remainder of these tutorials are devoted to exactly that. But for a moment, take time to consider the wider implication - that communication is the glue that holds everything together. Here are a few examples. 9013

1. A school of fish swims lazily through the water beneath the sea. Suddenly, the entire school turns as one and flits off in a new direction.

Surely it is some form of communication that permits the school to move with such precision. But which? Visual - each fish watching the one in front? Through a sense of sound? Or of smell? Jeremy Campbell comments on the biological role of communication 9023 9024 9025

...communication is not confined to radios, telephones, and television channels. It occurs in nature, wherever life exists. The genes are a system for sending chemical messages to the protein factories of the cell, instructing them to make a living organism. The human being is the most complex communications network on earth. - Campbell 1982, 67

Thus, communication is not merely speech among humans. It includes the many different kinds of messages that connect organisms of all kinds. And more than that, communication plays a role in the chemical and electrical systems that constitute the organisms.

2. Electrons orbit the nuclei of three atoms, one an oxygen atom and two of hydrogen. The result is a molecule of "water."

This might be a situation in chemistry, perhaps, or physics, but what could it have to do with communication? In response let us offer the words of Nobel Prize-winning Chemist Ilya Prigogine as he discusses the behavior of certain chemical "clocks" that change color with astounding regularity.

Such a degree of order stemming from the activity of billions of molecules seems incredible, and indeed, if chemical clocks had not been observed, no one would believe that such a process is possible. To change color all at once, molecules must have a way to "communicate." The system has to act as a whole. We will return repeatedly to this key word, communicate, which is of obvious importance in so many fields, from chemistry to neurophysiology. - Prigogine and Strengers 1984, 148

Communication, then, is not merely a characteristic of humans, or indeed of living organisms. It is present at the deepest levels of our material universe.

3. A couple purchases a car and pays for it by writing a check.

The notion of "money" covers much more than the bills and coins that we might have in our pockets. It includes checks, credit cards, stocks, and the many other devices that we use to record our relative wealth. Furthermore, the value of objects - the car in this example - is not fixed. Value is established in part by negotiation between the buyer and the seller. In fact, "money" seems to be very much a communication process.

4. Finally, consider a situation in which a home computer wakes itself at midnight (the hour at which the rates go down), dials the telephone number of an on-line data service, transmits the proper access codes for the service, downloads a particular data file, signs off, hangs up, saves the file to its disk, and turns itself off.

This kind of machine-to-machine communication has become increasingly common since the late-1950s (when computers began to be manufactured and sold in large numbers). Over the same time period, computers have become smaller and smaller, until today some machines - automobiles, for example - contain many computers that "talk" to one another continually to control and manage the machine.

Perhaps one of the most useful of these is the telephone system itself. Each telephone is a computer terminal, and when we dial a number, we send a program to the central phone computer asking it to locate and "ring" a terminal somewhere in the system.

Interestingly, it was the study of telephone transmissions that led to the development of one of the most widely used models of communication. That model is described in the next section. 9019

THE SHANNON/WEAVER MODEL OF COMMUNICATION

As was said earlier, communication might be thought of as the glue that holds a system together. Communication occurs when one part of the system becomes a transmitter and creates or produces a relationship, called the signal, that travels through space and time to make contact with a second part part of the system, the receiver. These terms are taken from the model of communication that was first introduced by Claude Shannon and Warren Weaver in the late 1940s. The next diagram shows a simple version of the model.

When communication is considered from this point-of-view, any of the various parts of the model may become the focus of study.

• A focus on the the transmitter, for example, might produce questions such as: where do messages come from? And how are they prepared for transmission?

• A focus on the the signal might suggest questions such as: what is a signal, exactly? How do signals move from place to place?

• Or, a focus on the receiver might suggest questions such as: does the receiver receive precisely the same signal that the transmitter transmitted? How does the reception of a message affect the receiver? Must the receiver be affected at all?

These and other questions lead to additional insights into the nature of the communication process.

Clearly, the signal is generated by the transmitter and "noticed" by the receiver, therefore, it must be something physical. Further thought suggests that the signal represents a pattern, or a disturbance, in some substance that forms part of the environment of both transmitter and receiver. The transmitter and receiver are immersed in this substance, which is usually called the medium of communication. The transmitter creates a signal by shaping, changing or disturbing the medium, and the receiver notices the signal by recognizing these changes.

For example

• In human speech the medium is the air. Signals are patterns or "waves" formed in the air by the vocal cords of the transmitter and noticed by the ear of the receiver.

• In dolphin communication the medium is water. The signals are patterns or "waves" formed in the water by one dolphin and noticed by another.

• In computer communication the medium is an electric current. Signals are patterns in a flow of electrons that are produced within the transmitting computer and detected by the receiving computer.

• In skywriting the medium is smoke. The signals are patterns of smoke drawn by a moving airplane and noticed by those on the ground.

When communication is observed, it is often the case that the signal captured by the receiver is not identical to the signal generated by the transmitter. Sometimes, and somehow, the signal changes as it travels from one to the other. This behavior is explained by noticing that there are ways that the signal might be interfered with as it travels through the medium. The Shannon/Weaver Model illustrates this by adding a term called noise.

And, in order to emphasize path of the signal, this more complex version of the model also specifies that a certain part of the medium, called the channel, directly connects the transmitter and receiver. In a perfect communication process, the signal would travel along the channel with no interference at all, even though other signals might be moving through the same medium outside of the channel. In the real world, however, most signals are subject to varying amounts of noise.

Here are some examples of how signals flow from transmitter to receiver via well-defined channels, and of how noise sometimes gets into the flow.

• A telephone cable package consists of bundles of single, insulated wires wrapped together and coated with plastic or similar substances. Each wire in the bundle is a channel, capable of carrying one signal. The bundles of wire group these channels together so that many signals may travel in the same direction. The cable is insulated to prevent noise, however, you may be talking to someone one day when a lightening flash from a nearby thunderstorm generates an electrical charge that interferes with the signal and adds static, or noise, to your phone call. 9014

• In a lecture hall you might notice that only the professor speaks. The fact that all but one person are quiet, creates a "silent" channel that allows the sound of the professor's voice to flow unimpeded to the ears of the students. However, in the midst of a particularly uninteresting lecture, some students might begin to whisper among themselves. As these sounds creep into the channel and combine with the professor's sound waves, the lecture becomes garbled and "noisy" to students in the back of the room.

• In a print medium, such as this book, the signals are patterns of ink pressed to a white piece of paper. A channel is formed by forcing the print to take on certain forms such as sentences, paragraphs, pages and chapters. Furthermore, only certain patterns of ink are acceptable. This channel, known as "spelling," may be enforced by a computer program that checks each word to make sure that it is acceptable. Nonetheless, noise creeps in. In fact, noise of this kind has affected this document. The descovery and description of this noise is left as an exercise for the reader. 9009 9010 9011 9022

• THE COMMUNICATION PROCESS
  Communication is a fundamental, universal process that serves to connect senders and receivers of messages through space and time.

• HUMAN AND NON-HUMAN COMMUNICATION
  Communication connects many kinds of senders and receivers, including ones that are not human, and even ones that are not alive.

• CONTENT AND CODE
  Although even very simple messages can convey meaning, many communication systems make use of organized, complex patterns of messages.

  

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