What is Redundancy in Information Theory?

A communication or message will generally contain one or more redundancies in order to avoid misinterpretation. Redundancy involves repeating or giving context to a communication to avoid miscommunication or misinterpretation. The Wikipedia defines redundancy as “the use of words or data that could be omitted without loss of meaning or function; repetition or superfluity of information”. Redundant information however shouldn’t be viewed as undesirable. Redundancy when used correctly, is a powerful and necessary tool for all communication including advertising and marketing.

Redundancy in Action

Military and police radio communication utilizes this by saying letters as words like fox for f, f being the message and ox being the redundancy. This is done because just stating a letter would make the communication more likely to be misinterpreted. T could sound like V or P. Saying Tango instead of T conveys a T to the person on the other end of the transmission much more efficiently and with less opportunity for error. The same principle of message redundancy can be used in other areas of communication.

Now a less obvious but just as prevalent example of redundancy in a message would be including an image in a blog post. One could argue that the image isn’t there for aesthetics but to make the transmission of the blogs title and message clearer. An extreme example would be a blog titled “How to find and Apple” if one just glances at the title they might be confused as to whether the blog was about a computer or a fruit.
If there is a picture to go along with the title that shows someone in a apple orchard then message would be clearer. The picture and title are redundant and make the message transmission more effective.

Another example of common redundancy is when a video contains spoken audio that is unclear and captions are added. The viewer seeing the written transcript now along with the audio hears the words for exactly what they are. The written word thus becomes a redundancy for the spoken word.

Redundancy in Evolution

Human beings have evolved over the millennium to be better communicators. They have also evolved to utilize redundancy in communication. People use redundancy unconsciously. Performing hand gestures while speaking seem to be hard “hard wired” into the human brain. Therefore it might be safe conclude that hand gestures are an examples of evolved redundancy. One might make assumption that the ability to communicate by hand gesture evolved before spoken word. Potentially Making the ability to speak originally a redundancy of hand communication.

Though redundancy is often routine and unconscious it is helpful to be aware of redundancy in all communications. Effective use of redundancy will make communication more efficient and effective.