Neural correlates of phenomenological attitude toward perceptual experience
Phenomenology is one of the most promising approaches to study conscious experience. It holds that a rigorous study of conscious experience requires a transition in the subject from the "natural attitude" (NA) to the "phenomenological attitude" (PA). NA describes our ordinary stance, in which our attention is directed at external objects and events. PA is a distinctive, reflective stance in which our attention is directed at our conscious experience itself. Despite its theoretical importance in philosophy and science of consciousness, the neural mechanisms underlying PA remain unknown. To clarify this point, we developed a novel behavioral task in which participants alternate between NA and PA in relation to their stimulus-evoked subjective experiences. Participants are presented with two sentences and requested to identify the one that best captures their experience. These sentences are designed to induce either NA or PA. We found that participants had lower error rates but slower reaction times in the PA condition compared to the NA condition, suggesting a difference beyond task difficulty. Using fMRI, we also found that multivoxel activation patterns in the premotor cortex, posterior parietal cortex, supplementary motor area, and cerebellum successfully classified the task conditions. Furthermore, the activation strength in these regions was lower in the PA condition, indicating that PA depends on neural processes that suppress action-related information. These findings provide the first evidence for the neural signature of PA, contributing to a better understanding of phenomenological method and its underlying neural mechanisms. Significance statementPhenomenology is one of the most promising approaches to study conscious experience. A key step is a transition from the natural attitude (NA)--where our attention is directed at external objects and events--to the phenomenological attitude (PA)--where our attention is directed toward our conscious experience itself. However, the neural processes underlying PA remain unclear. This study aimed to clarify this point by analyzing fMRI signals measured during a cognitive task that forced participants to repeatedly alternate between NA and PA. We observed that multiple action-related brain regions exhibited different activation patterns between NA and PA. Our findings provide the first neuroscientific evidence that illuminates the core process of the phenomenological method.