Advanced robot interfaces are unnecessary for effective psychological health interventions

Depression is prevalent among young adults, many of whom encounter obstacles to accessing traditional interventions. This study investigated whether the modality of robotic delivery influences outcomes when administering identical psychological health intervention content. We compared three modalities, a text-based chatbot, an audio bot, and a video telepresence robot, each delivering the same imagery-enhanced interpretation bias modification (eiIBM) intervention. Forty-nine young adults with depressive symptoms ( M _age = 22.71, SD = 3.30) were randomly assigned to one of the three robot conditions and completed six eiIBM sessions over two weeks. An additional control group ( n = 18) received no intervention. User experience was assessed using the I-PEFiC framework, and measures of depression severity and interpretation biases were collected. All three robot modalities yielded comparable outcomes, with substantial reductions in depression symptoms (Hedges' g = 1.11–1.33) and approximately 40 % decreases in negative interpretation biases. Bayesian analyses focusing on the modality provided substantial evidence for the absence of differences between modalities regarding intervention outcomes (BF_incl < 0.026). Notably, user experience emerged as a significant predictor of intervention efficacy: participants who reported positive user experiences exhibited markedly greater reductions in interpretation bias (Cohen's d > 3.0) regardless of the robot modality. These findings suggest that, when intervention content is standardized, increasing the sensory richness of the delivery modality does not enhance intervention outcomes. For structured cognitive interventions such as eiIBM, the fidelity of content delivery and the quality of user experience are more critical determinants of effectiveness than the sensory richness.