Ownership and cognitive connectedness with placebo objects predict pain-related behavoiral responses - evidence from two randomized controlled studies

Placebo analgesia has traditionally been understood to require the active administration of treatment. This study investigated whether cognitive connectedness with an owned placebo analgesic could enhance analgesia even without active application. Two pre-registered randomized controlled experiments were conducted. In Study 1 (N=121), healthy participants were randomized to one of four conditions under explicit verbal suggestions: (1) possessing a placebo cream with induced self-object connection (EXP1), (2) possessing a placebo cream with induced self-object disconnection (EXP2), (3) possessing a pain-irrelevant cream (CO1), or (4) possessing no cream (CO2). Pain responses were assessed using a Cold Pressor Test (CPT). Participants in the self-object connection condition (EXP1) exhibited significantly higher pain threshold, longer pain tolerance, and greater likelihood of maintaining hand submersion compared to all other conditions (EXP2, CO1, CO2) (ps<.05). In Study 2 (N=66), participants were randomized to either a placebo-possession or no-possession condition, completed an Implicit Association Test (IAT) to measure implicit self-association with a placebo analgesic cream, and then underwent the CPT. Participants in the placebo-possession condition demonstrated stronger implicit self-association with the placebo cream, which significantly predicted enhanced analgesic responses (ps<.05). Across both studies, cognitive connectedness to a placebo analgesic consistently amplified pain-related behavioral outcomes. These findings demonstrate that placebo responses can be elicited through psychological connectedness with a placebo object, independent of active treatment administration. The results offer a preliminary cognitive account of how possession may shape pain-related responding, providing an initial framework for future studies exploring cognitive pathways and developing low-cost, psychologically grounded interventions.