By Dr. Ken Broda-Bahm:
In voir dire, sometimes you want to choose a strategic and indirect way of asking, and sometimes you just want to come straight out and ask the question directly. In an interesting illustration of the difference between the two, Jeremy Dean's Psyblog recently shared the story of what must have been a "slap-my-head" moment for the social scientists involved. You see, there has been a long-running interest in the psychology of narcissism, defined as self-centeredness combined with feelings of high entitlement and low empathy for others. But here is the funny part: For almost four decades, the standard way to measure individual narcissism was through a psychometric scale known as the "Narcissistic Personality Inventory," (Raskin & Hall, 1979). This scale is comprehensive, detailed, composed of seven factors (authority, superiority, exhibitionism, entitlement, vanity, exploitativeness, and self-sufficiency), and includes forty questions in total. More recently, however, a research team (Konrath, Meier, & Bushman, 2014) discovered that most of the value of that scale could be captured in a single question. And that question boils down to, "Are you a narcissist?"
This perspicuous shift is captured in what the researchers, with probably a little bit of vanity, call the "Single Item Narcissism Scale," SINS for short. The single item is, "To what extent do you agree with this statement: 'I am a narcissist' (Note: The word 'narcissist' means egotistical, self-focused, and vain)." Participants answered on a seven-point scale ranging from "not very true of me" to "very true of me." In a total of 11 studies involving 2,250 research participants, the researchers found that the single item measure has a level of agreement ("convergent validity" to the wonks) that is at least as good as other measures of narcissism and carries similar correlation sizes. One implication for lawyers and trial consultants in voir dire is a reassuring one: You don't always need the fancy scale, and can sometimes rely on a single-pointed question. But for me, the most interesting point is why the direct question works so well in this case, because that also points out the reasons why it does not work so well in other contexts. So in this post, I'll directly look at the direct question: when and why it works and when and why it doesn't.