Written texts are central to formal education. The reading (consumption) and writing (production) of texts constitutes a great deal of the activity of students and teachers, and usually forms the basis for assessment and sorting. For this reason, a whole range of fields have taken up the problem of "literacy" (or rather literacies) in formal schooling, not only applied linguistics, rhetoric, and education, but also sociology, semiotics, psychology, social psychology, socio-linguistics, linguistic anthropology, communication studies, and so on. Similarly, learning in workplace and civic contexts is also highly dependent on literacy, and the relations between formal schooling and other contexts for learning are also mediated by alphanumeric texts.