viz.

By John Jones

The two main theories of semiotics that have influenced the study of visual texts are those of linguists Ferdinand de Saussure—later elaborated on by Roland Barthes—and Charles Sanders Peirce. Saussure/Barthes's theory suggests that there is no direct relationship between a word and the thing which that word is meant to represent. Rather, the connection between the two is culturally negotiated and liable to change if cultural conditions suggest it. Barthes built on Saussure's theories, dividing the sign into two parts: the signifier and the signified. According to Barthes, the signifier is the word or sound that is associated with the thing or phenomenon in the world that is being referred to, while the signified is the meaning that is associated with that signifier. According to this theory, the way in which signs make meaning can be explained through the identification of the signifier and the signified.

Peirce's theory approaches the subject of signs differently. While, like Saussure, he recognizes the difference between the word and its meaning, he also categorized the different kinds of relationships signs could have with the objects in the world that they were associated with. He defined three different way these relationships could be explained: iconic, indexical, and symbolic. While Peirce's description of a symbol is similar to that of Suassure in that it is a relationship to something in the world, but a relationship that only exists insofar as it is created through the workings of an established code like language, he also adds to this system the iconic and indexical relationship. Iconic relationships are ones where the object in question is depicted. An iconic sign of a horse would be an image that is recognizable as a horse. The indexical relationship is one where the object in question is indicated through some effect produced by that object.

For example, while the word "car" is a symbolic representation of a car, made through the operation of the English language, a picture of a car would be an iconic representation, and a set of tire tracks in mud would be an indexical sign of the car, indicating that a car made them.

These terms can be a helpful tool for discussing the effects of visuals on an audience or explaining how an image depends on outside infromation to be interpreted. Take the case of the indexical sign as an exmaple. To interpret the image of tire tracks as indicating the presence of a car, an audience must have some previous knowledge of cars and their physical makeup. Further, while it might be generally accepted that tire tracks are the result of a car having been in a certain place at a certain time, this is not necessarily the case.