The role of a UX researcher in product design is to gather insights about user behaviors, needs, and motivations through various methods such as interviews, surveys, and usability testing. By understanding the target audience, UX researchers provide valuable data that informs design decisions to enhance user experience. Their findings help identify pain points and opportunities for improvement, ensuring the product aligns with user expectations. Additionally, UX researchers collaborate closely with designers and developers to create user-centric solutions and validate design concepts through iterative testing.