ok the grossest oversimplification ever put forward on the ideas known as Semiotics:
Semiotics the study of signs and signifiers: A literary and philosophical study/science of the representative (and misrepresenative) nature of language and linguistics. The roots of this study lead from the early 20th century theories of Ferdinand de Sasseur (Course in General Linguistics, 1916). Semiotics and related linguistic theory/study often implicate the frame of reference of the audience of the work as the chief determinant of the signified image or work. The theory exploits the abstract nature of language; language and art can never really represent the plasticity of reality and thus is always in conflict with nature/reality. This thought is highly exploited in Rene Magritte's painting Ceci n’est pas une pipe.
In addition to this mediative effect, messages (art,news,media, etc) of course can be twisted by the mediating influences of the author and the culture at large. By filtering the work through the dominant paradigms of the author/culture, a work can be fetishisized into a belief system emergent only from these a prioris. This cultural assumption thus reinforces the paradigm further removing objective reference.
Again another gross oversimplification of the facts and story but consider this: a fascinating convergence happened in theories of cosmology in the same decades that semiotic theory was being hatched. A young physics uspstart named Albert Einstein was thrusting upon the world the theory that the study of our universe was dependent observers frame of reference. His theories show how the observer can effect the observered natural phenomena. Again the Viewer biases the Viewed. Put that in your Ceci n’est pas une pipe and smoke it!
more reading if you are truly masochistic: