The idea of two distinct types of thinking has been highly influential within psychology and beyond. De Neys refers to these types of thinking as intuiting and deliberating and identifies core aspects of the interaction between both. In doing so, he provides a valuable contribution to the literature.

It remains unclear, however, how the distinction between intuiting and deliberating itself should be conceptualized. There are at least three levels of analysis at which the distinction can be made: (1) at the descriptive level in terms of subjective experience (i.e., the experience of intuiting and deliberating); (2) at the functional level in terms of the environmental conditions under which thinking occurs (e.g., whether it requires time or the absence of other tasks); and (3) at the mental level in terms of mental mechanisms and the mental representations on which they operate (e.g., associative or propositional representations).

Like others before him (e.g., Kahneman, Reference Kahneman2011), De Neys draws the distinction in terms of speed and effort: Though intuiting is used to refer to fast and effortless thinking, deliberating refers to slow and effortful thinking. It is not entirely clear whether speed and effort are conceptualized at the descriptive level (i.e., a subjective experience) or at the functional level (e.g., actual time required; interference by other tasks) but De Neys does not seem to situate the distinction at the mental level. For instance, he argues that “both single- and dual-process theories focus on the interaction between intuition and deliberation” and that his “criticism and recommendations equally apply to single- and dual-process models” (target article, Introduction, para. 5). Assuming that the distinction between single- and dual-process models is situated at the mental level, these arguments suggest that the distinction between intuiting and deliberating needs to be made at another level than the mental one.

We definitely agree that there are many benefits of separating to-be-explained phenomena (such as intuiting and deliberating) from explanatory mental mechanisms (e.g., spreading of activation; propositional reasoning; see Hempel, Reference Hempel1970; Hughes, De Houwer, & Perugini, Reference Hughes, De Houwer and Perugini2016). However, in his target article, De Neys does so in a manner that is not entirely coherent. Most importantly, he allows for the concept of low effort deliberation. If deliberation is by definition effortful (either descriptively or functionally), then how can it be effortless? In our opinion, the idea of low effort deliberation makes sense only if deliberation is situated at the mental level, for instance, when postulating a single-process theory in which all deliberating involves the manipulation of propositional representations (i.e., propositional reasoning). Hence, by allowing for the idea of low effort deliberation, De Neys seems to implicitly conceptualize deliberation at the mental level. We encourage him to be more explicit about how exactly he draws the distinction between intuiting and deliberating, most importantly, with regard to the level of analysis at which this distinction is situated.

In the remainder of this commentary, we discuss two ideas for clarifying the nature of intuiting and deliberating that, in our opinion, have not yet been given sufficient consideration in the literature. First, when delineating intuiting and deliberating, we see merit in taking seriously the descriptive level. In recent years, important progress has been made in studying a variety of subjective experiences such as the experience of confidence (e.g., Desender, Boldt, & Yeung, Reference Desender, Boldt and Yeung2018), sense of agency (Marcel, Reference Marcel, Roessler and Eilan2003), conflict (e.g., Desender, Van Opstal, & Van den Bussche, Reference Desender, Van Opstal and Van den Bussche2014), making an effort (e.g., Naccache et al., Reference Naccache, Dehaene, Cohen, Habert, Guichart-Gomez, Galanaud and Willer2005), and the urge to err (e.g. Questienne, van Dijck, & Gevers, Reference Questienne, van Dijck and Gevers2018). We believe it would be interesting and feasible to study also the experience of intuiting and deliberating. This approach would draw attention away from the ontological and most likely unproductive debates about what is the “true” nature of intuiting and deliberating. It would also allow researchers to document the conditions under which people report intuiting and deliberating, as well as the possible differences in decisions produced under these conditions (i.e., to conduct functional research on intuiting and deliberating as descriptive phenomena). Finally, knowledge about these conditions and differences would help constrain theories about the mental mechanisms that produce the subjective experience of intuiting and deliberating.

Second, clarifying the nature of intuiting and deliberating not only requires specifying how they differ but also what they have in common. Both are typically thought of as instances of thinking but what is thinking? Here we see merit in conceptualizing thinking as a type of behavior (De Houwer, Reference De Houwer2022; De Houwer, Barnes-Holmes, & Barnes-Holmes, Reference De Houwer, Barnes-Holmes, Barnes-Holmes, Hayes and Hofmann2018). Functional psychologists have successfully explored the benefits of this approach with regard to a variety of cognitive activities such as perceiving (e.g., Skinner, Reference Skinner1963), memorizing (e.g., Guinther & Dougher, Reference Guinther and Dougher2014), and learning (De Houwer & Hughes, Reference De Houwer and Hughes2020). Conceiving of intuiting and deliberating as behavioral phenomena allows one to distinguish them at the descriptive level (i.e., as different subjective experiences; see De Houwer, 2022) or at the functional level (e.g., as relational responding in a slow or fast manner; see De Houwer et al., Reference De Houwer, Barnes-Holmes, Barnes-Holmes, Hayes and Hofmann2018; Hughes, Barnes-Holmes, & Vahey, Reference Hughes, Barnes-Holmes and Vahey2012) without making a priori assumptions at the mental level (i.e., about the mental mechanisms that allow for thinking as behavior). From this behavioral perspective, the primary aim of research is to understand the environmental conditions that moderate these phenomena. For this research, inspiration can be found in the extensive literature on known moderators of behavior in general (e.g., Catania, Reference Catania2013; Fisher, Piazza, & Roane, Reference Fisher, Piazza and Roane2011). For instance, it is likely that switching between the behavior of intuiting and the behavior of deliberating is heavily dependent on antecedents (i.e., discriminative stimuli) and consequences (i.e., reinforcers and punishers). In line with the functional–cognitive framework for research on psychology (De Houwer, Reference De Houwer2011; Hughes et al., Reference Hughes, De Houwer and Perugini2016), knowledge about the moderators of intuiting and deliberating not only has merit as such (i.e., it allows for prediction and control) but also facilitates the development of theories about the mental mechanisms that mediate these phenomena. In this way, combining descriptive and functional definitions with a behavioral perspective can provide a new impetus for both functional and cognitive research on intuiting and deliberating.