I love this topic! This is something really important to consider as user interviews fall into the category of self-report data. Knowing the common biases, such as social desirability, and also the own experimenter’s biases as you mentioned, the confirmation bias, should certainly be taken into consideration. So I completely agree with you, the field of psychology is very relevant for UX researchers. I’d even add quantitative methods as well. Surveys, for example, can quantify some user interview data, and even though they’re more difficult to be accurate to gather qualitative data, they do have the potential “anonymity” factor.