UX design is the process of enhancing customer satisfaction and loyalty by improving the usability, ease of use, and pleasure provided in the interaction between the customer and the product. Yes, this process is carried out by UX researchers. The most experimental team. They are the one who can give dozens of solutions to your problem. They experiment if something works, if it works they again experiment and find out why it worked.
They are the one who copy your behavior and can be like you. As explained by Wikipedia: “User research focuses on understanding user behaviors, needs, and motivations through observation techniques, task analysis, and other feedback methodologies.” Being you, they create different scenarios and experiment. They find what makes you easy and what makes you happy. They help you get the job done with minimal effort. They are the one to suggest better path towards your vision. They research on your experience so they are called User Experience (UX) researchers.
Knowing who the target customers are, and how to make their experience with your product the most rewarding or ‘delightful’ it can be, is the responsibility of the UX design team.
In a team if someone does not hesitate to ask you questions and irritate you will silly yet genuine questionnaire they are UX Researchers.