There is also a sixth part which is noise. Noise is interference in the channel, and causes a signal to be received that was not intended by the source.
The advantages of Shannon and Weaver's model are that it is in a simple, easily understood form; and that it is a general model that can be applied to most types of communication. The five main parts are self-explanatory; the only part that needs some description is the 'noise'. However, the model oversimplifies the process of communication and a number of important considerations have been excluded. In looking at the shortfalls of the transmission model I shall consider interpersonal communication, where source and destination are replaced by sender - message - receiver.
One of the problems with transmission models is that the source is the decision maker and that the destination is passive. The sender chooses a message to send, and the receiver simply receives that message rather than actively participates in the communication process. But communication is a two-way process, a complex system of signals passing back and forth between the participants. People talk to each other, there is never a 'one-sided' conversation, even if the other person is silent their body language and facial expressions may speak volumes! Transmission models also suggest that communication is always intended, that the sender always sets out to send a message to the receiver, but communication can be unintentional. As I have pointed out we communicate by body language and by facial expression, often revealing far more about our thoughts than by what we say. We do not always say what we mean (we may give conflicting signals), or mean what we say - "I'll kill you" is seldom meant literally! The message may reach the wrong destination by our failure to send it through the 'proper channel', so that it is communicated to someone other than the intended recipient.
Transmission models are linear, suggesting that we simply receive a message as it is sent, but we interpret the messages we receive bringing our own understanding to them. We do not just absorb information, we analyse what we see and hear in order to make sense of it.
There is no exact meaning in any given message, what is meant by the sender may not be the same as what is understood by the receiver. We create meaning according to our personal experiences and our own understanding. So the same message may mean different things to different people. Often there are several ways to interpret a message, and we decide which is appropriate according to the situation at the time. For example, if the receiver is in a bad mood they are more likely to interpret what is communicated in a negative way, looking for meanings that could be construed as confrontational.
Another problem with the fact that the transmission model is linear is that it does not allow for feedback. We rely on the response to a message in order to monitor how successfully we are communicating, and to make necessary adjustments. If the signals that we get from our listener suggest that they have misinterpreted our message or have simply not heard it then we can alter the way in which we communicate in order to meet their needs. Our response to feedback also makes th For instance, a parent may impart excellent advice to their child but if the child would rather be out playing with their friends they are unlikely to pay attention to what is being said and the communication will not be successful. Words often fall on 'deaf' ears! However, if the child asks the parent for advice and the parent is happy to oblige then there is a shared purpose and the parent's message is likely to be successfully communicated.
Time is a factor in communication: people change in their attitude and in their relationship with each other even within a conversation. We often say that we have 'brought someone round to our way of thinking' as their attitude changes when we successfully get our message across to them. And people can sometimes adopt a superior air when it becomes apparent that they know more about a particular subject than the other person. And over a period of time there are definite changes within a relationship and purposes are redefined; for example, the way a child and parent communicate alters to reflect their changing needs as the child grows and develops. You would not talk to an adolescent in the same way as you would talk to a small child, nor would you get the same responses.
Another of the ways in which the basic transmission model fails to represent communication is that it does not allow for context. We need a contextual frame in which to make sense of things, whether it be social, historical, cultural, political or other. Communications can break down because of a lack of cultural understanding, that which is implicit within one culture may not be so in another. We make sense of what is said according to the context in which it is said, and we have shared cultural understandings which literally 'go without saying'. Problems arise when we try to communicate with others from different cultures without allowing for the fact that they may not share our cultural understanding. Contextual frames also help us to communicate in an appropriate manner, for example it would not be considered socially acceptable to laugh and joke when told of someone's death.
The relationship between people is also important, the way in which we communicate is influenced by the status of the person we are communicating with. For example, a worker is not likely to discuss the conditions of his workplace in the same manner with his boss as he is with his co-worker. And we are more likely to listen carefully (and absorb) something that is said by a person whom we consider to be 'in authority', or is an expert in a particular field. We also differentiate in the way we communicate with people of the same or opposite sex, when communicating with the opposite sex we tend to adopt a different approach (which varies according to purpose!) to the relaxed, comfortable manner that we assume when communicating with others of the same sex. We communicate differently with children than we do with other adults - we use simpler language and adopt a position of power, so we are aware that an age gap makes a difference to the way we communicate with one another.
The transmission model does not consider the medium that is used. But the medium is not neutral: it plays an important role in communication. The medium that we choose tells the receiver something of our intention when sending the message, and there are many social conventions that tell us which medium is appropriate. For example, it would not be considered acceptable to fax a lover to tell them that the relationship was over - convention dictates that it should be done face-to-face. And people have definite preferences as to the medium used: many people prefer personal letters to be hand-written as this indicates that the sender has made a special effort to communicate in this way, and many people feel that when someone writes by hand they give something of themselves by the very act of forming the characters on the page. The same convention dictates that it is preferable to type/word process business letters, as it is considered to be more formal and obviously less personal that your own hand. Careful choice of the medium can dramatically enhance or negate the effect of the message. Some media are chosen for practical reasons, some are more suited to the purpose than others - for instance, when writing a report or essay it is more practical to use a word-processor rather than a pen as corrections are much easier (as is the life of the reader!), simply because of the technological differences between the two.
In conclusion, the transmission model is not an accurate reflection of the complex nature of communication. It fails to allow for the construction of meaning which is so vital to our success in communicating with one another. The model does not allow for the context of the communication, nor for the purpose; it does not consider the relationship between the parties, and it does not allow for the influence of the chosen medium. Communication is a complex, inter-active process which relies on the active participation of both sender and receiver, and cannot be accurately represented by a linear system.