Placebo Analgesia Does Not Generalize From Pain to Interoceptive Abilities: A Preregistered Exploratory Study

Placebo pills reliably reduce pain. Pain perception is tied to increased arousal and heart rate. Heart rate perception is, in turn, closely related to interoceptive signals processing, for example, pain and autonomic regulation. However, no studies so far have systematically examined the generalizing versus specific effects of placebo analgesia in transferring from pain to the interoception of cardiac signals. In this preregistered, exploratory study, we aim to investigate whether the placebo analgesia effect on pain may generalize to the perception of one's own heartbeat. We recruited 88 healthy participants (47 female, 41 male), of which half (23 female, 21 male) underwent a deceptive placebo analgesia induction. Using the Heartbeat Counting Task and the MAIA questionnaire, we derived three interoceptive dimensions: interoceptive accuracy, sensibility (at both task-related and trait levels), and awareness. Despite a robust placebo analgesia effect, no difference between the placebo and the control group was found in any of the interoceptive dimensions. These findings were supported by post hoc Bayesian analyses, which indicated moderate evidence for this absence of a group difference. Our findings thus do not indicate a generalization of the placebo analgesia effect from pain to cardiac interoceptive awareness. Studies such as the present one are important to better understand the perception of different bodily systems and their connection in humans.