{"ID":2860149,"CreatedAt":"2026-06-01T04:54:23.091178241Z","UpdatedAt":"2026-06-01T04:54:23.091178241Z","DeletedAt":null,"paper_url":"https://arxiv.org/abs/2510.05449","arxiv_id":"2510.05449","title":"Bloom: Designing for LLM-Augmented Behavior Change Interactions","abstract":"Large language models (LLMs) offer novel opportunities to support health behavior change, yet existing work has narrowly focused on text-only interactions. Building on decades of HCI research on effective behavior change interactions, we present Bloom, an application for physical activity promotion that integrates an LLM-based health coaching chatbot with existing design strategies and UI elements. As part of Bloom's development, we conducted a redteaming evaluation and contribute a safety benchmark dataset. In a four-week randomized field study (N=54) comparing Bloom to a no-LLM control, we observed important shifts in psychological outcomes: participants in the LLM condition reported stronger beliefs that activity was beneficial, greater enjoyment, and more self-compassion. Both conditions significantly increased physical activity levels, doubling the proportion of participants meeting recommended weekly guidelines, though descriptively, we observed no advantage for the LLM condition in short-term physical activity levels. Instead, our findings suggest that LLMs may be more effective at shifting mindsets that precede longer-term behavior change.","short_abstract":"Large language models (LLMs) offer novel opportunities to support health behavior change, yet existing work has narrowly focused on text-only interactions. Building on decades of HCI research on effective behavior change interactions, we present Bloom, an application for physical activity promotion that integrates an L...","url_abs":"https://arxiv.org/abs/2510.05449","url_pdf":"https://arxiv.org/pdf/2510.05449v2","authors":"[\"Matthew Jörke\",\"Defne Genç\",\"Valentin Teutschbein\",\"Shardul Sapkota\",\"Sarah Chung\",\"Paul Schmiedmayer\",\"Maria Ines Campero\",\"Abby C. King\",\"Emma Brunskill\",\"James A. Landay\"]","published":"2025-10-06T23:31:18Z","proceeding":"cs.HC","tasks":"[\"cs.HC\"]","methods":"[\"Large Language Model\",\"Language Model\"]","has_code":false}