Laymen learn to read photographs the way they do headlines, skipping over them quickly to get the gist of what is being said. Photographers, on the o… - Howard S. Becker

Even in the simplest societies, no two people learn quite the same cultural material; the chance encounters of daily life provide sufficient variation to ensure that. No set of cultural understandings, then, provides a perfectly applicable solution to any problem people have to solve in the course of their day, and they therefore must remake those solutions, adapt their understandings to the new situation in the light of what is different about it.

Photographers learn to interpret photographs in that technical way because they want to understand and use that ‘language’ themselves (just as musicians learn a more technical musical language than the layman needs). Social scientists who want to work with visual materials will have to learn to approach them in this more studious and time-consuming way

Imagine you are doing a woodworking project, perhaps making a table. Fortunately, you needn't make all the parts yourself. Some are standard sizes and shapes - lengths of two by four, for instance - available at any lumberyard. Some have already been designed and made by other people - drawer pulls and turned legs. All you have to do is fit them into the places you left for them, knowing they were available. You want to make an argument instead of a table. You have created some of the argument yourself, perhaps on the basis of new data or information you have collected. But you needn't invent the whole thing. Other people have worked on your problems or problems related to it, and have made some of the pieces you need. You just have to fit them in where they belong. Like the woodworker, you leave space, when you make your portion of the argument, for the other parts you know you can get. You do that, that is, if you know that they are there to use. And that's one good reason to know the literature: so that you will know the pieces are available and not waste time doing what has already been done.