Intuitive decision making as a gradual process: Investigating semantic intuition-based and priming-based decisions with fMRI

Introduction: Intuition has been defined as the instantaneous, experience-based impression of coherence elicited by cues in the environment. In a context of discovery, intuitive decision-making processes can be conceptualized as occurring within two stages, the first of which comprises an implicit perception of coherence that is not (yet) verbalizable. Through a process of spreading activation, this initially non-conscious perception gradually crosses over a threshold of awareness and thereby becomes explicable. Because of its experiential basis, intuition shares conceptual similarities with implicit memory processes. Based on these, the study addresses two research questions: (1) Is the gradual nature of intuitive processes reflected on a neural level? (2) Do intuition-based decisions differ neurally from priming-based decisions? Methods: To answer these questions, we conducted an fMRI study using the triads task and presented participants with coherent word triads that converge on a common fourth concept, and incoherent word triads that do not converge on a common fourth concept. Participants had to perform semantic coherence judgments as well as to indicate whether they immediately knew the fourth concept. To enable investigating intuition-based and priming-based decisions within the same task and with the same participants, we implemented a conceptual priming procedure into the coherence judgment task. We realized this by priming participants with concepts associated with incoherent triads in separate priming blocks prior to the coherence judgments. Results: For intuition-based decisions, imaging results mainly revealed activity within the orbitofrontal cortex, within the inferior frontal gyrus and the middle temporal gyrus. Activity suppression in the right temporo-occipital complex was observed for priming-based decisions. Conclusions: With respect to research question 1, our data support a continuity model of intuition because the two intuitive stages show quantitatively distinct brain activation patterns. Regarding research question 2, we can draw the preliminary conclusion of a qualitative difference between intuition-based and priming-based decisions.