Have you ever wondered whether someone you know—perhaps a friend, a colleague, or even a close family member—is a narcissist? How would you find out? You could try to get the person of interest evaluated by a licensed clinical psychologist, probably for a steep fee. Alternatively, you might try to administer the most widely used measure of narcissism in research yourself: the 40-item Inventory (NPI).

Yet I have a feeling that neither of these options seem plausible to most people.

At Indiana University, Sara Konrath and her colleagues recently sought to address some of the challenges associated with administering such long questionnaires, and in response, developed the so-called Single-Item Narcissism Scale (SINS).

At first, my colleague Seth Rosenthal (Yale) and I were skeptical about the idea that one simple question—Are you a "narcissist"?—could accurately identify narcissists, given that narcissism is such a complex and multidimensional personality trait. (See my post, "Everything You've Always Wanted to Know about Narcissism.")

Given our initial skepticism, paired with a dedication to replication science in social-personality research, we decided to see if we could replicate these initial positive findings with a sample of over 2,000 American adults.

The results of our new study were recently published in the journal Personality and Individual Differences. In a nutshell, we were able to replicate most of the authors' initial findings and we reached two main conclusions:

The single-question measure does indeed correlate positively with the more complex 40-item NPI questionnaire (i.e., they both seem to measure narcissism). Importantly, while the NPI-based measure seems to conflate narcissism with normal, or healthy (due to questions that ask people about more normative traits like " " and " "), the single-item measure did not correlate with self-esteem at all! In other words, the measure does not appear to capture people who might have some milder "lower-order" traits—which implies that the question actually singles out the "hard-line" narcissists pretty well.

By now, I am sure you are to know what the magic question actually is. It is probably much simpler than you imagine. If you want to find out whether someone is a narcissist, simply ask them:

Are you a "narcissist"?

This may seem counterintuitive at first, and it certainly doesn't always work to ask people directly about their personality traits, but the case of narcissism is unique. True narcissists do not appear to view their narcissism as a bad thing. In fact, they are likely to be proud of it! Indeed, a number of recent studies have shown that narcissists often admit that they behave in explicitly narcissistic ways, that they happily describe themselves as arrogant, braggy, etc., and even strive to be more narcissistic! Narcissists also appear aware that other people view them less positively than they view themselves, yet simply don't care.

My co-author, Seth Rosenthal, suggests that there are several interesting factors about the scale itself that may play an important role in its validity:

The scale asks respondents to identify with the trait as a noun “I am a narcissist,” rather than the adjective “I am narcissistic.” That gives narcissists the opportunity to stake their claim to a special that they know most people would reject—i.e., providing an affirmative response to the question gives them the opportunity to boost their ego. The one-item survey comes with a definition of narcissism: "Are you a 'narcissist'? The word ‘narcissist’ means egotistical, self-focused, and vain." If a more severe set of descriptive traits had been chosen (like entitled, exploitative, arrogant, not ), it might have been too difficult for people to endorse the item.

Of course, self-reports aren't perfect. People may say one thing, and the truth may be another. In addition, a single-question like that doesn't tell us much about the "type" of narcissism we're dealing with or whether particular narcissistic traits (e. ., grandiosity) are more pronounced than others (e.g., lack of empathy), which is important because we know different aspects of narcissism can influence behavior in different ways.

In conclusion, while a single-question narcissism assessment might not give us a detailed personality profile, it seems to measure the bottom line pretty well.

In other words, if you want to find out whether someone you know is a narcissist, it might be worth simply asking them.

Copyright (2016). Sander van der Linden, Ph.D.