Measuring Interoception: The Phase Adjustment Task

Background: Interoception, the perception of one’s internal bodily state, has been repeatedly linked to mental health, and atypical interoception proposed as a transdiagnostic risk factor. Despite the clinical importance of interoception, existing measures are suboptimal as they are susceptible to physiological and psychological confounds. Furthermore, existing measures are lab-based, limiting both scalability and accessibility. Methods: Here we describe a novel measure, the Phase Adjustment Task (PAT), administered via smartphone. During the task tones are presented at the participant’s heartrate (recorded via smartphone camera), but out of phase with heartbeats. Participants are required to adjust the phase relationship between tones and heartbeats until they are synchronous. Results: Data from 124 participants indicates both variance in performance across participants and that performance is not affected by physiological or strategic variables. Furthermore, results are consistent with previous data on the temporal characteristics of cardiac interoception. Conclusions: Given its validity, accessibility and scalability, the PAT task is suitable for large-scale clinical interoception research.