Source–message–channel–receiver model of communication

The source–message–channel–receiver model is a linear transmission model of communication. It is also referred to as the sender–message–channel–receiver model, the SMCR model, and Berlo's model. It was first published by David Berlo in his 1960 book The Process of Communication. It contains a detailed discussion of the four main components of communication: source, message, channel, and receiver. Source and receiver are usually distinct persons but can also be groups and, in some cases, the same entity acts both as source and receiver. Berlo discusses both verbal and non-verbal communication and sees all forms of communication as attempts by the source to influence the behavior of the receiver. The source tries to achieve this by formulating a communicative intention and encoding it in the form of a message. The message is sent to the receiver using a channel and has to be decoded so they can understand it and react to it. The efficiency or fidelity of communication is defined by the degree to which the reaction of the receiver matches the purpose motivating the source.

Each of the four main components has several key attributes. Source and receiver share the same four attributes: communication skills, attitudes, knowledge, and social-cultural system. Communication skills determine how good the communicators are at encoding and decoding messages. Attitudes affect whether they like or dislike the topic and each other. Knowledge includes how well they understand the topic. The social-cultural system encompasses their social and cultural background.

The attributes of the message are code, content, and treatment as well as elements and structure. A code is a sign system like a language. The content is the information expressed in the message. The treatment consists of the source's choices on the level of code and content when formulating the message. Each of these attributes can be analyzed based on the elements it uses and based on how they are combined to form a structure.

The remaining main component is the channel. It is the medium and process of how the message is transmitted. Berlo discusses it primarily in terms of the five senses used to decode messages: seeing, hearing, touching, smelling, and tasting. Depending on the message, some channels are more useful than others. It is often advantageous to use several channels simultaneously.

The SMCR model has been applied to various fields, such as mass communication, communication at the workplace, and psychology. It also influenced many subsequent communication theorists. It has been criticized for oversimplifying communication. For example, as a linear transmission model, it does not include the discussion of feedback loops found in many later models. Another common objection is that the SMCR model fails to take noise and other barriers to communication seriously and simply assumes that communication attempts are successful.