The heartbeat counting task largely involves non-interoceptive processes: Evidence from both the original and an adapted counting task.

The heartbeat counting task (HCT) is among the most frequently used measures of interoceptive accuracy (i.e., IAcc). Growing concerns, however, have been raised regarding the validity of this task, as well as the validity of the IAcc scores that are derived from it. In the present study, healthy participants (N = 123) performed both the original task and an adapted version of it that stressed the importance of reporting only their perceptually felt heartbeats. In the original task, we found that participants report relying on three different strategies (i.e., detection of heartbeats in a specific body location, detection of heartbeats in a diffuse way and heart rate estimation) to complete the task. In the adapted task, we found that IAcc scores are drastically reduced (about 50%) when asking participants to avoid relying on non-interoceptive signals and to only report the heartbeats they perceive. These findings confirm that the HCT task is largely contaminated by the influence of non-interoceptive processes. Implications of these findings for research on interoception are discussed.