Reflections on reflection: the nature and function of type 2 processes in dual-process theories of reasoning

I present a critical discussion of dual-process theories of reasoning and decision making with particular attention to the nature and role of Type 2 processes. The original theory proposed that A: Type 2 processes serve to rationalise and support intuitive choices. For most of its history, however, such accounts have emphasised instead B: Type 2 processes reason to conclusions or decisions. B is part of the "received theory" of dual processing, often inaccurately linked to the idea that Type 2 reasoning is necessary for correct solutions. While not mutually exclusive, the evidence for each proposition is assessed. I then present a default-interventionist model which incorporates both propositions A and B. This is consistent with evidence that reasoning to support the default intuition is the norm, although intervention may also occur. Other issues discussed include (1) whether we should treat Type 2 as well as Type 1 processing as originating from multiple systems, (2) whether we need to separate postulate "Type 3" processes to explain underlying cognitive control and attention switching, and (3) whether recent experimental observations of "logical intuitions" undermine the default-interventionist approach. I point to some new directions in which research on dual processes may proceed.