That readers understand more of a text when they know something of the content schema is now well established. Bransford & Johnson (1972) found that knowledge of the subject matter of a text was of fundamental importance in understanding the text; Steffensen, Joag-Dev & Anderson (1979) found that texts based on known cultural background knowledge were easier to understand than similar texts based on different cultures; Carrell (1987) found similar results in investigating the effects of both cultural and formal schemata.
A distinction is sometimes made between formal and content schemata (Carrell, 1987) but we can deal with formal schemata under rhetorical organisation. Apart from the distinction between content (background knowledge) and cultural schemata, other distinctions have been made; Context/ concreteness-abstractness, Bransford & Johnson, (1972); context/ transparency, Carrell (1983); familiarity, Anderson, Reynolds, Schallert & Goetz (1977), Carrell (1983), but it is unclear whether these distinctions have any basis in reality and for present purposes we can conflate these categories.
Carrell (1983) found that non-native readers did not utilise background knowledge to make appropriate predictions about the meaning of a text - a surprising finding.
However, Lee (1986) found that asking non-native readers to recall the text in their L1 revealed that they had utilised background knowledge.
Nowadays most researchers would agree that background knowledge of all kinds is of fundamental importance in text comprehension.
"Reading experts generally agree that "more information is contributed by the reader than by the print on the page. That is, readers understand what they read because they are able to take the stimulus beyond its graphic representation and assign it membership to an appropriate group of concepts already stored in their memories….. The reader brings to the task a formidable amount of information and ideas, attitudes and beliefs. This knowledge, coupled with the ability to make linguistic predictions, determines the expectations the reader will develop as he reads. Skill in reading depends on the efficient interaction between linguistic knowledge and knowledge of the world." (Clark and Silberstein 1977: 136-137, cited in Carrell & Eisterhold, 1988:75,76)
It is easy to lose sight of the importance of background knowledge and its effect on readability. Although it is often assumed that writers have particular readers in mind, they may not appreciate the difficulties readers face when there is a lack of shared background knowledge. Writers in specialist fields often assume more background knowledge in their readers than is warranted. What is obvious to specialists may not be so for others:
"If readers lack prior content knowledge in the domain, ideas presented in the text may seem disconnected even though connections among the ideas seem "obvious" to domain experts". (Goldman 1997:367)
Although mainly concerned with textual characteristics of readability, we cannot dismiss schemata as a contributory factor in the readability of a text. First of all a text is more or less readable according to how far the reader is able to activate the necessary schemata required for comprehension, so the reader's background knowledge has to be taken into account.
Secondly readability can only be assessed by adopting some measure of how the text has been comprehended by a reader or group of readers and comprehension must involve schemata: integrating new textual information with background knowledge.
"Whether we are aware of it or not, it is this interaction of new information with old knowledge that we mean when we use the term comprehension" (Anderson & Pearson, 1988:37)
Since content is so important it is not surprising that it influences the way the text is organised - for example that introducing topic early in a paragraph facilitates reading (Kieras, 1978,1980), a feature which is mirrored at sentence level in the normal organisation of given/new, topic comment.
Although for the purposes of this section we have conflated cultural and content schemata, cultural factors may influence reading in other ways. Aebersold & Field provide a useful summary of these difficulties:
"…cultural differences are pervasive, and they constitute the largest category of factors that influence L2/FL reading. Generally speaking, the areas of L2/FL reading most influenced by cultural organisation fall into six groups. 1) Cultural orientation and attitudes towards text and purpose for reading, 2) Cultural orientation and the types of reading skills and strategies used in the L1, 3) Cultural orientation and the types of reading skills and strategies appropriate in the L2/FL, 4) Cultural orientation and beliefs about the reading process, 5) Cultural orientation and knowledge of text types in the L1 (formal schemata), 6) Cultural orientation and background knowledge (content schemata)." (Aebersold & Field 1997:28-33 (adapted))