Two Kinds of Process or Two Kinds of Processing? Disambiguating Dual-Process Theories

Dual-Process Theories (D-PTs) claim there are two qualitatively different types of processes in the human brain-mind. Despite forming the basis for several areas of cognitive science, they are still shrouded in ambiguity: critics erroneously attack D-PTs as a whole (e.g., Evans and Stanovich Perspectives on Psychological Science , 8(3), 2013), the qualitative/quantitative distinction is not clear enough (De Neys Perspectives on Psychological Science 16 (6): 1412–1427, 2021; Dewey 2022) and, given this criterion, deciding between qualitative or quantitative differences may even be scientifically irrelevant (De Neys 2021). As a way of disambiguating the discussion and clarifying what exactly means to claim the existence of a second type of process, I define two possible categories of D-PT: The substantial and the instrumental. In the substantial case, Type 2 processes are subpersonal level ones. In the instrumental case, Type 2 processing is a personal level phenomenon that does not necessarily imply subpersonal level Type 2 processes. Discussing the different implications of each of the categories, I use as a main example to illustrate the ambiguity – and the exercise of disambiguation – the model proposed by Evans and Stanovich (2013), making clear its substantial character, and contrast it with Frankish’ (2009) – a clear case of instrumental D-PT. Finally, I discuss the contributions this distinction can make. By making the discussion clearer, it can provide a relatively unanimous framework for dual- and single-process theorists (the instrumental version) and clearer desiderata for those wishing to defend the substantive one.