A particularly good example of the processes involved in using background knowledge was provided by Sanford and Garrod (1981), who presented readers with a short text, one sentence at a time. Their text begins with the following two sentences.

Most people who are asked to read these sentences report that they think John is probably a schoolboy. Since this piece of information is not directly stated in the text, it must be an inference. Other inferences, for different readers, are that John is walking or that he is on a bus. These inferences are clearly derived from our conventional knowledge, in our culture, about “going to school,” and no reader has ever suggested that John is swimming or on a boat, though both are physically possible, if unlikely, interpretations.

 An interesting aspect of the reported inferences is that they are treated as likely or possible interpretations that readers will quickly abandon if they do not fit in with some subsequent information. Here is the next sentence in the text.

On encountering this sentence, most readers decide that John is, in fact, a teacher and that he is not very happy. Many report that he is probably driving a car to school. Then the next sentence is presented.

Suddenly, John reverts to his schoolboy status, and the inference that he is a teacher is quickly abandoned. The final sentence of the text contains a surprise.

This type of text and manner of presentation, one sentence at a time, is rather artificial, of course. Yet the exercise involved does provide us with some insight into the ways in which we “build” interpretations of what we read by using a lot more information than is presented in the words on the page. That is, we actually create what the text is about, based on our expectations of what normally happens. In attempting to describe this phenomenon, researchers often use the concept of a “schema” or a “script.”