Some people seem amazing when you first meet them. They are confident, funny, and well dressed. Psychologists found that people with a strong focus on themselves are often popular at first.

But this does not last. In one study, small groups of students met once a week. At first, these people seemed nice. After seven meetings, others saw them as arrogant. So don't judge people too quickly.

In a new class, some people stand out right away because they seem confident and charming. Research suggests that many of them score high in narcissism, a personality trait involving a strong desire for attention and admiration. In a German study, 73 new university students introduced themselves to the group and rated each other. People higher in narcissism were more popular at first because of their stylish clothes, confident gestures, and humorous way of speaking.

However, a Canadian psychologist found that this popularity fades. Students met in small groups once a week for seven weeks. People who tended to present themselves too positively were seen as pleasant at the first meeting but as arrogant and hostile by the seventh.

People who make a dazzling first impression are not always the ones we end up liking most. Research on narcissism, a personality trait found to varying degrees in everyone rather than a clinical diagnosis, helps explain why. In a German study, 73 first-year students introduced themselves to the group, and those higher in narcissism were rated as more popular. Their flashy clothing, charming facial expressions, self-assured body language and humorous remarks did much of the work.

Even entitlement and exploitativeness, tendencies that are harmful in the long run, looked attractive at first sight. That early glow did not last. In a Canadian study, students met weekly in small groups for seven sessions. Those with a strong tendency to self-enhance were viewed favorably after the first meeting, but by the last they were seen as arrogant and hostile.

A later German study, again limited to university students, video-recorded about 300 of them in weekly group interactions for three weeks. It separated two sides of narcissism. Admiration seeking produced confident behavior and initial appeal, while rivalry led to aggressive, arrogant conduct. Week by week, the benefits of admiration seeking faded and the costs of rivalry grew.