The role of a UX researcher in product design is to understand user needs through qualitative and quantitative research methods. They gather insights through techniques like interviews, surveys, and usability testing to identify user pain points and preferences. This information helps inform the design process, ensuring that products are intuitive and meet user expectations. By collaborating with designers and developers, UX researchers bridge the gap between user behavior and product functionality, ultimately enhancing user experience and satisfaction. Their findings contribute to creating products that resonate with the target audience, driving overall success.