Scientists have developed and validated a new method to identify which people are narcissistic: just ask them.
In a series of 11 experiments involving more than 2,200 people of all ages, the researchers found they could reliably identify narcissistic people by asking them this exact question (including the note):
To what extent do you agree with this statement: "I am a narcissist." (Note: The word "narcissist" means egotistical, self-focused, and vain.)
Participants rated themselves on a scale of 1 (not very true of me) to 7 (very true of me).
(How narcissistic are you? Take the test here.)
Results showed that people's answer to this question lined up very closely with several other validated measures of narcissism, including the widely used Narcissistic Personality Inventory.
The difference is that this new survey – which the researchers call the Single Item Narcissism Scale (SINS) – has one question, while the NPI has 40 questions to answer.
"People who are willing to admit they are more narcissistic than others probably actually are more narcissistic," said Brad Bushman, co-author of the study and a professor of communication and psychology at The Ohio State University.
"People who are narcissists are almost proud of the fact. You can ask them directly because they don't see narcissism as a negative quality – they believe they are superior to other people and are fine with saying that publicly."
Bushman conducted the study with Sara Konrath of the Indiana University Lilly Family School of Philanthropy (formerly of the University of Michigan) and Brian Meier of Gettysburg College. Their results appear in the journal PLOS ONE.
Understanding narcissism has many implications for society that extend beyond the impact on the individual narcissist's life, Konrath said.
"For example, narcissistic people have low empathy, and empathy is one key motivator of philanthropic behavior such as donating money or time to organizations."
"Overall, narcissism is problematic for both individuals and society. Those who think they are already great don't try to improve themselves," Bushman said.
"And narcissism is bad for society because people who are only thinking of themselves and their own interests are less helpful to others."
Bushman emphasized that SINS shouldn't be seen a replacement for the longer narcissism questionnaires. The NPI and other instruments can provide more information to researchers, such as which form of narcissism someone has.
"But our single-item scale can be useful for long surveys in which researchers are concerned about people getting fatigued or distracted while answering questions and possibly even dropping out before they are done," Bushman said.
He noted that if it takes a person 20 seconds to answer the single question in the SINS measure, it would take him or her 13.3 minutes to answer the 40-question NPI.
"That is a big difference if you're doing a study in which participants have to complete several different survey instruments and answer a long list of other questions," he said.
The 11 different experiments took a number of different approaches to determine the validity of SINS. Some used undergraduate college students, while others involved online panels of American adults.
One experiment found that SINS was positively related to each of the seven subscales of the NPI which measure various components of narcissism (vanity, exhibitionism, exploitativeness, authority, superiority, self-sufficiency, and entitlement).
Another study found that that participants tended to have similar scores on SINS when tested 11 days apart. One experiment replicated past work that showed people scoring high in narcissism were more likely to engage in risky sexual behaviors and had difficulty maintaining long-term committed romantic relationships.
People who scored higher on narcissism on the SINS had both positive and negative outcomes, Bushman said. They reported more positive feelings, more extraversion, and marginally less depression.
But they also reported less agreeableness, and more anger, shame, guilt, and fear. In addition, people scoring high on SINS showed negative interpersonal outcomes, such as having poor relationships with others and less prosocial behavior when their ego was threatened.
The advantage of SINS compared to other measures, Bushman said, is that it allows researchers to identify narcissists very easily.
"We don't think SINS is a replacement for other narcissism inventories in all situations, but it has a time and place," he said.
Explore further: Can narcissists be moved to show empathy?