Not answering questions isn’t limited, then, to interpersonal situations. In psychological research, investigators may not gather all the information they need because participants find the questions too personal and anxiety -provoking. Such questions may involve requests for sexual history, mental health symptoms, employment status, and opinions on controversial topics. It’s also possible that participants just become bored and don’t feel like completing the study. In any case, as the authors note, “Attrition is rarely innocuous” (p. 147).