De Neys W. On
Perspectives on Psychological Science.
Popular dual-process models of thinking have long conceived intuition and deliberation as two qualitatively different processes. Single-process-model proponents claim that the difference is a matter of degree and not of kind. Psychologists have been debating the dual-process/single-process question for at least 30 years. In the present article, I argue that it is time to leave the debate behind. I present a critical evaluation of the key arguments and critiques and show that—contra both dual- and single-model proponents—there is currently no good evidence that allows one to decide the debate. Moreover, I clarify that even if the debate were to be solved, it would be irrelevant for psychologists because it does not advance the understanding of the processing mechanisms underlying human thinking.
Time to Move On
The dual vs single process model debate has not been resolved, it can be questioned whether the debate
can be resolved, and even if it were to be resolved, it will not inform our theory development about the critical processing mechanism underlying human thinking. This implies that the debate is irrelevant for the empirical study of thinking. In a sense the choice between a single and dual process model boils—quite literally—down to a choice between two different religions. Scholars can (and may) have different personal beliefs and preferences as to which model serves their conceptualizing and communicative goals best. However, what they cannot do is claim there are good empirical or theoretical scientific arguments to favor one over the other.
I do not contest that the single vs dual process model debate might have been useful in the past. For example, the relentless critique of single process proponents helped to discard the erroneous perfect feature alignment view. Likewise, the work of Evans and Stanovich in trying to pinpoint defining features was helpful to start sketching the descriptive building blocks of the mental simulation and cognitive decoupling process. Hence, I do believe that the debate has had some positive by-products.