Refinements of the phase adjustment task (PAT 2.0)

In 2021 a new measure for the assessment of cardiac interoceptive accuracy-the Phase Adjustment Task (PAT)-was developed that overcomes several limitations of existing methods and can be administered using a smartphone application. In this report, we describe several refinements to the PAT. These include: (1) triggering tones from the detection of the heartbeat via the smartphone camera, rather than using an algorithm for predicting the occurrence of the next heartbeat; (2) technical amendments to enable implementation on iPhones with multiple cameras; (3) changes to instructions and (4) changes to the collection of confidence ratings to improve participant understanding and the utility of confidence ratings for interpretation of results; (5) the introduction of new practice trials to improve clarity; (6) changes to the analysis approach to identify cardiac phase-based heartbeat perceivers; (7) a review of the use of continuous scores; (8) a reanalysis of data comparing PAT performance in supervised laboratory settings and unsupervised remote settings using the new analysis method, and (9) the implementation of additional measures to discourage participants from checking their pulse. In this paper we outline our justification for these changes and provide details of where researchers can access the materials required for implementing the PAT and analyzing data. Finally, we provide further recommendations for implementation.