When the Body Counts Its Own Heartbeats: How We Measure Interoception Falls Apart Under Scrutiny

Interoception – the brain's reading of signals from inside the body – has become one of the busiest constructs in clinical psychology. Blunted or distorted interoception is now invoked to explain panic, depersonalization, eating disorders, alexithymia, and the affective flatness that mindfulness-based interventions aim to repair. Almost all of this work rests on a small set of cardiac tasks and on one electrophysiological index, the heartbeat-evoked potential. This study from the National Medical Research Center for Therapy and Preventive Medicine and the Higher School of Economics in Moscow did something the literature rarely affords: it ran three behavioral cardioception tasks and recorded the HEP in the same forty-eight volunteers, then asked whether these measures actually converge.

They largely do not. Heartbeat tapping and heartbeat counting agreed with each other across most scoring metrics, which is reassuring but also unsurprising, since both reward a participant who can estimate heart rate from general arousal rather than feel individual beats. Heartbeat discrimination – judging whether a tone falls in or out of sync with one's pulse – stood apart, correlating with neither. If these tasks indexed a single interoceptive ability, they should move together. Their divergence implies that what we casually call "interoceptive accuracy" is partly an artifact of which task was administered.

The more pointed result concerns the neural marker. Across the field, a larger HEP is read as stronger cortical representation of cardiac signals, and HEP differences are reported in anxiety, depression, and meditation studies as if the potential were a stable trait. Here the HEP refused to behave that way. It did not separate good from poor performers on any task, it was no larger when people actively attended to their heartbeats than when they rested, and it shifted with the specific task in play. A marker that varies with momentary task demands but not with measured ability is difficult to interpret as a fixed individual characteristic.

For clinicians, the caution is concrete. Interoception-based formulations and the body-awareness rationale behind contemplative interventions are scientifically plausible, but the instruments meant to operationalize them are noisier and less interchangeable than their routine use implies. A patient's score on one heartbeat task does not license claims about their interoception in general, and an HEP finding from one paradigm may not generalize to another. Body-awareness work remains worth doing; the measurement scaffolding underneath it needs to be read with appropriate skepticism.

Why the Heartbeat Became Psychology's Favorite Signal

The heart is convenient: it beats continuously, produces a clean electrical trace, and generates a cortical response that can be averaged from EEG. That convenience explains why cardiac interoception became the dominant operational definition of a far broader construct – yet the gut, lungs, and vasculature may carry interoceptive information that heartbeat tasks never touch.

What a Convergence Failure Means for Theory

When several measures of one supposed faculty fail to correlate, the cleaner conclusion is often that the faculty was never unitary. Interoception may be a family of partly independent processes – detection, attention, belief, metacognition – that no single heartbeat score can summarize.