But perhaps people have always been self-absorbed during and young adulthood, that glorious time when adult responsibilities have not yet begun.

I heard this argument a lot when one of my studies found that narcissism is markedly higher among college students in the 2000s compared to those in the 1980s. (The latest analyses can be found here; the original is here). But age can't explain the results of these studies, because they compare people of the same age (18 to 22), but at different points in time. Maybe 18 to 22-year-olds have always been , but 18 to 22-year-olds are now more narcissistic than 18 to 22-year-olds used to be.

Irrelevant as it is to this research, the argument that greater narcissism is universal to youth keeps popping up, and in some high-profile places. In an article in Perspectives in Psychological Science, Brent Roberts and his colleagues concluded that narcissism was a product of youth rather than of generation. Then today, the New York Times asked if every generation was self-absorbed on a blog related to a story covering his article.

Why is this argument more persistent than the animatronic rodent in a game of Wack-A-Mole, when it so obviously doesn't fit the data? (How can you say something is due to age when age doesn't vary?)

Two reasons. First, some researchers mistakenly concluded there was no generational change because they failed to control for a really big confounding variable. Do that, and the increase in narcissism is even stronger than what we originally found.

Roberts then did his own, one-time study, comparing narcissism scores among college students, their parents, and their grandparents. The college students had the highest scores, followed by their parents and then their grandparents. Voila! Narcissism must decrease as people get older; it's Developmental Me, not Generation Me, they concluded.

Except those parents and grandparents were a different generation than the college students -- they were born and grew up at a different time as well as being a different age. So the changes could be due to either age or generation. Thus his study could be seen as further confirmation that narcissism is higher among Generation Me (those now in college).

Admittedly, it sounds very plausible that people should get less narcissistic as they get older. More than likely, Jersey Shore's Mike "The Situation" won't flash his abs quite as much once he hits 60.

But no study has yet shown that narcissism decreases with age -- for that, you'd need a longitudinal study following people as they age, preferably from adolescence to middle age, completing the Inventory at every point. But that hasn't been done. The closest is a study following women from college to middle age using another measure of narcissism. So did women's narcissistic traits decrease as they aged? No --instead, as the women got older, their narcissism scores increased. This study was headed by Roberts (yes, the same one), who concluded that the cultural changes of the time period -- here, from the early 1960s to the late 1980s -- reflected the increasingly individualistic culture of the times. No argument from me there.

Here's the more interesting question -- how has the experience of adolescence and young adulthood changed over the generations? My co-author W. Keith Campbell puts it this way: "Of course people have always said young people are self-absorbed. They are. The difference is that cultures used to have rites to transform young people into adults, like male circumcision or walkabouts. Today if you're 28 years old and living in your Mom's basement eating Ho Hos and playing Xbox you will be called an 'emerging adult.'"

Although it's tough to wax nostalgic for ritual male circumcision at adolescence (ow), he's got a point: Our current culture does not require young men and women to "grow out" of their self-absorption for a very long time. That has some advantages, as they can explore their identities and take more time to find their way. But there are downsides, and greater narcissism is likely one of them.

Will Generation Me grow up, and grow out, of some of their self-absorption? Probably -- life is a good cure for narcissism. But they're starting at a higher level, and reaching adulthood at a time when narcissism is celebrated. Just ask Mike "The Situation." He's 28.