How many dual-process theories do we need? One, two, or many?

Abstract Dual-process theories of cognition are to be found everywhere in psychology. This chapter addresses whether there is a need to have this great multiplicity of theories, or whether there is one grand unifying dual-process theory that can incorporate them all. It argues that such theories fall into two distinct groups from the viewpoint of the cognitive architecture they imply. There is also a third notion (cognitive styles) that can all too readily be confused with such two-process accounts. A minimal definition of the difference is that type 1 processes are fast, automatic, low effort, and have a high processing capacity; and that type 2 processes are slow, controlled, high effort, and have a high processing capacity.