An ELT Glossary : Schemata

Definition : A schema (usual plural : schemata) is a mental representation of a situation, topic, text etc which creates expectations and aids (or may aid) interpretation of similar contexts. Different writers divide schemata in different ways and use different terms, but some of the most common categories, and  most relevant to language teaching include Social Schemata, Content Schemata, Formal Schemata, Linguistic Schemata, and Ideological Schemata. 
  • Social schemata - your knowledge of what happens in specific situations or events: for example,  my "exam schema" includes candidates sitting at individual tables in silence completing a written test, a clock on the wall, an invigilator present etc . However, this is  culturally determined and reflects my experience with British style exams. An Italian's "exam schema" might be of an oral interview by a panel of teachers, watched by other students waiting to be examined themselves.
  • Content schemata - your background knowledge of a topic. I'm interested in astronomy and read quite a lot of popular science magazines like "New Scientist" and "American Scientific" for articles on the subject. I can usually follow them, but if I were reading a paper in a scientific journal, I'd be unlikely to understand it. My background knowledge  of the specific topic would be insufficient to allow me to follow and interpret the argument. 
  • Formal schemata - your knowledge of the rhetorical organisation and conventions of a text. For example, if I'm reading an expository text, I'll expect it to be organised into paragraphs, each dealing with a specific topic or subtopic, with topic sentences used to specify what each paragraph deals with and connectives used to highlight the relationship between ideas. If on the other hand I'm reading a narrative text. I'll expect a chronological ordering and relation of past events. For specific genres of narrative text, it won't surprise me if other features are included. Eg I'd expect the use of direct speech in both press reports and novels; and in novels possibly the use of "flashback" technique" - the relation of a later event which the reader doesn't fully understand first, in order to make them want to read on.   
  • Linguistic schemata - your knowledge of and ability to decode the linguistic features of a text - ie your ability to decode the letters or phonemes, understand their combination into words, the meaning of those words, the combination of those words into syntactic units etc. Linguistic schemata are therefore a matter of bottom up processing. Eg when you see the letters "p" "i" and "n" while reading, if they are preceded and followed by a space you recognise that they form the word "pin", whereas if they are preceded by "s" or followed by "e" you decode two completely different words. Similarly, if faced with a word like steradian you will probably lack the full linguistic schemata needed to understand it, and what you do have may lead you astray. What do your linguistic schemata tell you about the form. Is it a verb? Noun? Adjective? Adverb? Decide, then google it to check!.
  • Ideological schemata - expectations of attitudes to various social, political etc issues. The danger of raising issues which may create ideological dissension in the classroom has led to the so-called "PARSNIPS policy" in EFL publishing - the avoidance in textbooks of the topics politics, alcohol, religion, sex, narcotics, isms (eg terrorism or feminism), and pork. See Thornbury (2010) for a critique of this policy. 

Cultural factors affecting schemata : As the above examples show, your various schema regarding a subject affect your top-down processing of what is said. For example, my schema for "weddings" includes church /white dress / rice etc. Therefore if I hear "There were loads of pigeons in the churchyard pecking up the rice", I will assume a wedding has taken place. If for eg cultural reasons, or because you lack technical knowledge, your schema for the topic is different from the speaker's/writer's, then comprehension problems may arise.

In the classroom,  relevant schemata can be activated prior to a reading or listening activity by eg asking learners to predict from the title or a brief description of the context what it will be about, what will happen, what people will do/say etc. This can :

a) aid bottom up processing: discussing a topic, roleplaying a situation etc  means that learners will have the relevant language (lexis, functional exponents etc) at the forefront of their minds when listening to or dealing with the text. Expecting the words   will facilitate decoding, and therefore overall comprehension, when/if they occur in the text.

b) aid top-down processing, or bring out any differences in cultural expectations which are liable to impede comprehension, allowing the teacher to deal with them.

References and Further Reading   

Constantinides, M. Advance Organizers - How they Connect the Reading Experience

Cook, G.  Schemas  ELTJ - Key Concepts in EFL
Thornbury, S. (2010) T is for Taboo

And for more depth...

Brown G and Yule G, Discourse Analysis, Cambridge - see Chap. 7