Abstract
Growing demand for freshwater turtles as pets has fueled illegal trade and accelerated wild population declines, underscoring the need for theory‐based demand‐reduction interventions. We conducted a three‐part randomized controlled trial with active turtle keepers ( n = 1800) in China to test conservation‐ and legality‐framed messages by comparing purchase intention before and after the intervention between treatment and control groups for two globally threatened species: Indochinese box turtle ( Cuora galbinifrons ) and the big‐headed turtle ( Platysternon megacephalum ). Drawing on an extended theory of planned behavior (TPB), we modeled frame‐specific claim agreement, attitudes, subjective norms, perceived behavioral control, and perceived self‐efficacy with structural equation models. Conservation and legality messages significantly reduced purchase intention relative to a no‐message control (mean declines of 0.37–0.84 points on a 5‐point scale across treatment arms) primarily through indirect psychological pathways. Conservation messages heightened harm‐based evaluations and moral concern, whereas legality messages strengthened illegality appraisals and deterrence‐related cognitions. Across models, claim agreement was a key proximal antecedent, subjective norms consistently predicted lower self‐efficacy, and self‐efficacy emerged as the most proximal positive predictor of intention. Perceived behavioral control showed no direct effect. Species‐specific differences in pathways, suggestive of reactance in the big‐headed turtle conservation model, reflected variation in legal signals and market narratives. Our findings highlight the importance of claim agreement, injunctive norms, and species context in shaping intervention outcomes. Demand‐reduction campaigns may be more effective when tailored to species‐specific legal and market conditions and when normative cues are paired with feasible alternatives and practical guidance that makes compliance achievable.