Interoceptive Accuracy and Panic
Lori Zoellner and Michelle Craske’s 1999 analogue experiment: infrequent panickers vs nonanxious controls on the Schandry mental-tracking task, with a caffeine arousal induction and a safety-information manipulation layered on top. It is the wiki’s first first-hand replication of the founding group difference — Ehlers & Breuer (1992) — and the only source here that set out to manipulate arousal within an anxious sample and measure what it did to the count.
Why it matters to the wiki
Two things. First, it corroborates, from an independent American lab and in a non-patient sample, the result the whole panic-interoception literature rests on: people prone to panic count their heartbeats more accurately. Everything the wiki has on that finding until now traces to Ehlers’s own Marburg programme (read first-hand in ehlers-1993-interoception-panic) or to the reanalysis she co-authored. Zoellner & Craske are outside that lineage and get the same group difference.
Second, and more usefully, it runs the two experiments the wiki’s open debates most wanted run — does raising arousal raise the score? and does anxiety raise the score? — and the answers land squarely on the validity question, though not the way the authors intended.
The replication, and how clean it is
Infrequent panickers were more accurate at baseline (44.7% vs 61.7% error) and across all nine trials (35.6% vs 53.0%), and the group difference survived covarying self-rated certainty, perceived heartbeat speed, and perceived pounding. That last point is worth holding: the difference is not explained by panickers merely feeling more confident or more cardically aroused during the task. It is a difference in the count itself.
The authors also did the validity housekeeping Ehlers pioneered and found the same things: near-universal undercounting (≈89% in both groups), and no correlation of error with either general heart-rate knowledge (r=−.14) or time-estimation ability (r=.18), which rules out the two obvious non-perceptual strategies. So on the pro-validity side’s own terms this is a solid replication.
The caffeine experiment is a near-miss, and the miss is instructive
Zoellner & Craske’s stated aim was to test whether physiological arousal drives accuracy — the hypothesis the wiki’s cardiodynamic confound answers yes to (a louder heart is an easier signal). They induced arousal with 600 mg of caffeine, confirmed it raised a composite autonomic index across trials, and found accuracy flat. They conclude “no direct relationship between interoceptive accuracy and arousal level.”
But the composite rose through skin conductance, EMG, expired CO₂ and skin temperature — not heart rate, which showed no trial effect at all (their footnote 1). And the cardiodynamic account is not about arousal in general; it is about the amplitude of the cardiac signal specifically. A manipulation that raises electrodermal and muscular arousal while leaving the heart unchanged is orthogonal to it. Their null is real and worth having — accuracy does not ride on general sympathetic/metabolic arousal — but it is not evidence against the cardiodynamic confound, and read carefully it points mildly the other way: the one channel that did not move (cardiac) is the one accuracy is supposed to track, and accuracy did not move either. The decisive experiment (raise the cardiac signal, watch the score follow) is Antony et al.’s (1995) exercise result, where heart rate really did rise and accuracy really did follow it. This study is that experiment attempted on the wrong variable.
The safety-information manipulation reinforces the same point from a second angle: no-safety information raised autonomic arousal (skin conductance especially) but changed neither felt anxiety nor accuracy. Cognitive manipulation of the body left the score alone.
The state-anxiety effect is the study’s sharpest datum, and it is double-edged
Within each participant, error fell as state anxiety rose — greatest at their lowest-anxiety trials (54.7%), least at their highest (45.8%) — with no sign of the hypothesized breakdown at extreme anxiety. Zoellner & Craske read this as state anxiety magnifying attention to bodily cues, and connect it to the attentional-bias tradition: anxiety sharpens the deployment of attention to the body, so the anxious perceive their hearts better. On that reading the study is a within-subject demonstration of Ehlers’s “habit of attending to bodily cues” turned into a state manipulation, and a proposed resolution of why some studies find the panic group difference and some do not (uncontrolled state anxiety as a moderator).
The wiki has to record the competing reading, because the study cannot exclude it. Error here is unsigned (|actual − perceived|/actual), and in a task where nearly everyone undercounts, any process that makes a participant count more moves them toward the true value and lowers their error without improving perception. The Van der Does artefact is exactly such a process: an anxious person who expects a racing heart counts faster and scores as more accurate. Zoellner & Craske’s finding — higher anxiety, lower error — is precisely what that artefact predicts, and they never report whether the anxious trials’ counts shifted up (which would betray the artefact) or whether perception genuinely sharpened. Their attention account and the artefact account make the same prediction and the data do not separate them. See is-the-heartbeat-counting-task-valid.
That the same effect reads as “attention sharpens perception” or “anxiety inflates the count toward truth” is not a flaw the authors could have designed away without a signed-error analysis — it is the counting task’s structural ambiguity showing through a clean within-subject manipulation. It is one of the better illustrations in the wiki of why the validity debate is not a caveat but a rival measurement model.
Where it sits
Not a duplicate: no prior Zoellner or Craske page exists, and this is a distinct study from Ehlers (1993) (different lab, different sample, an original experiment rather than a review) though it replicates Ehlers & Breuer (1992). Not a hard contradiction of anything here — it corroborates the pro-validity group difference and its novel results (the non-cardiac arousal null, the within-subject anxiety effect) enrich the open validity and dose debates without overturning existing content. Its lasting value is the pair of near-experiments: the arousal manipulation that missed the cardiac channel, and the anxiety manipulation that improved the score in a way the wiki’s two camps read in exactly opposite directions.