Semiotic object relations theory (SORT) as the basic CAT theory?

Abstract The chapter explores the concept of semiotic object relations theory (SORT), which was originally formulated by Anthony Ryle in 2002. To develop this theory, it was necessary to present two conceptual modifications to the original procedural sequence model (PSM). The chapter presents the concept of object-directed activity and a revised concept of the sign as the building blocks of the SORT. It goes on to discuss the relationship between this conception and standard CAT theory. It is suggested that the SORT operates as a metatheory, providing a broad explanatory frame without necessitating radical changes in the current concepts or clinical practices.