It is not necessary to have a PhD to be a UX researcher, but having a advanced degree in a relevant field such as psychology, human-computer interaction, or cognitive science can be helpful. UX research typically involves using a variety of methodologies to understand how people use and interact with technology, and a background in these areas can provide valuable knowledge and skills. Ultimately, the most important qualities for a UX researcher are an understanding of the principles of good design and the ability to conduct thorough and rigorous research.