Rainer Schandry

The most-cited researcher in this wiki without, until now, a page — which is why this one exists. “Schandry (1981)” and “Schandry et al. (1993)” appear on heartbeat-detection-task, interoceptive-sensitivity, dunn-2010-listening-to-your-heart and oldroyd-2019-attachment-interoception as load-bearing citations, and neither paper is in raw/. He arrives properly with Pollatos, Kirsch & Schandry (2005), where he is third author.

The instrument

Schandry (1981) is the origin of the heartbeat-counting task: count your heartbeats silently over timed intervals without taking your pulse; score by comparing counted to recorded beats. Nearly every empirical claim about “interoceptive accuracy” in this wiki traces to it — seth-2013-interoceptive-inference, oldroyd-2019-attachment-interoception, dunn-2010-listening-to-your-heart, pollatos-2005-interoceptive-awareness-erp all use it or its variants, and the interoceptive-taxonomy’s “accuracy” construct is defined largely by it.

The same paper reported the founding finding: heartbeat perception relates to emotional experience. That claim, and the measure that produced it, are the twin inheritances.

The finding that undercuts his own task

Worth stating plainly, because it is unusual and it matters more than the task’s other criticisms.

Schandry, Bestler & Montoya (1993) found that stroke volume predicts heartbeat-detection performance: the more blood the heart moves per beat, the better people count their own beats. The signal to be detected varies in strength between people and within a person across states.

This is the cardiodynamic confound, and it is corrosive to the construct his 1981 task was built to measure. If a “good perceiver” is partly someone with a louder heart, then heartbeat-counting scores are not a clean index of perceptual skill, and any group difference where the groups plausibly differ in autonomic tone — which is most clinical, stress, and anxiety comparisons — is confounded at the root. Anything that raises sympathetic outflow makes the task easier by making the heartbeat louder rather than the perceiver better. Chronically increased sympathetic outflow has since been proposed as a route to high measured accuracy (Paulus & Stein 2010).

That the confound comes from the task’s own author is worth recording. It is a good scientific habit and a badly under-propagated result: the confound is cited far less than the task, and his own 2005 paper — on which he is an author — does not raise it, despite being a between-groups comparison of high and low scorers with no bodily measurement at all to rule it out. See heartbeat-detection-task.

The confound is now a manipulation, not a correlation

Added with the Van der Does et al. (2000) ingest, and it is the strongest thing that has ever happened to this section.

Schandry et al. (1993) is correlational: people with more forceful hearts count better. Antony et al. (1995), reanalysed in the 2000 pool, is experimental. Exercise participants, then re-run the task over seven trials while heart rate decays from ~130 to ~92 bpm. Measured accuracy rises while the heart is loud and returns to baseline by ~95 bpm. Twenty-five of 60 participants show the transient gain; exactly one becomes durably accurate. Panic patients, social phobics and controls behave identically and do not differ in actual HR at any trial.

Raise the amplitude of the signal and accurate perceivers appear. Let it fall and they dissolve. Nobody learned anything. That is the cardiodynamic account demonstrated rather than inferred, and it is the wiki’s single best piece of evidence that Schandry’s task scores signal strength rather than perceptual skill.

The inversion: his finding is used as evidence of validity

The thing worth knowing about the stroke-volume result is that its most prominent use in the literature is the opposite of this wiki’s.

Ehlers cites Schandry et al. (1993) as support for the task’s validity: if counting performance correlates with cardiodynamics, participants must be responding to real cardiac events, so the task measures cardiac perception (Van der Does et al. 2000 §1). This wiki, following Oldroyd et al. and Paulus & Stein (2010), carries the identical finding as the confound that undermines the task.

Both readings are coherent, and the disagreement is not about the data:

• Ehlers: the score tracks the heart → the task is about the heart → valid.
• This wiki: the score tracks the heart’s loudness → the task is about the signal, not the perceiver → the construct is wrong even though the measurement is real.

The exercise result adjudicates, and it splits the difference in a way that favours the wiki: Ehlers’s inference survives (real cardiac signal genuinely reaches perception, at sufficient amplitude), but the construct does not (a score you can raise with a treadmill is not measuring an ability). Recorded on is-the-heartbeat-counting-task-valid, where the dispute now has a page.

The irony is worth stating: the same 1993 correlation is the field’s evidence for the task and this wiki’s evidence against it, and Schandry has never adjudicated it. He devised the instrument, discovered the finding both sides use, and drew the sceptical conclusion from neither.

Position in the wiki’s argument

Schandry founds the tradition that Dunn audits. The 1981 finding (interoception relates to emotional experience) is the consensus; Pollatos et al. (2005) is an instance of it read first-hand; Dunn et al. (2010) fails to reproduce its main effect and reinterprets the whole relationship as a moderation. And the 1993 stroke-volume result is the single sharpest objection to the evidence on both sides of that dispute, since a louder heart is both easier to count and a bigger signal for Dunn’s interaction to work on.

Neither 1981 nor 1993 has been read first-hand here. Both are cited across four pages. Recorded as the wiki’s most consequential unread sources — see heartbeat-detection-task.