This seems to make sense intuitively, but as the authors - Brad Bushman of Ohio State University and Eddie Brummelman, a post-doctoral researcher at Holland's University of Amsterdam and Utrecht University - point out, this was not the prevailing explanation all along. Psychoanalytic theory suggested that narcissists were the result of parents who showed them too little warmth.
So Bushman and Brummelman pitted social learning theory - the idea that you learn through modeled behavior - against the psychoanalytic argument and found that, indeed, children learn their narcissism from parents who teach them that they are more than special.
The authors also wanted to determine what differentiated narcissists - who tend to be more aggressive and even violent than other people, and are at higher risk for depression, anxiety and drug addiction - from people with strong self-esteem. As mentioned above, parents who show their kids warmth and appreciation without promoting the idea that they are superior tend to raise children with solid self-esteem.
Previous studies have looked at narcissistic adults, but in 2008, Brummelman said in an interview, reliable testing instruments became available for young children. By the age of 7 or 8, he said, children develop the ability to describe whether they are happy with themselves and are very likely to compare themselves with others.
"It's an age when they maybe especially sensitive to parental influence," he added.
The researchers did note that they couldn't quite come out and show cause and effect.
"Of course, parental overvaluation is not the sole origin of narcissism," they wrote.
"... Like other personality traits, narcissism is moderately heritable and partly rooted in early-emerging temperamental traits. Some children, due to their temperamental traits, might be more likely than others to become narcissistic when exposed to parental overvaluation."
Aside from having to deal with someone like this, why should any of us care? Well, narcissism has been on the rise among Western youth in recent decades. Bushman wasn't available for an interview, but he put his concerns nicely when my colleague Rachel Feltman interviewed him for another study last summer:
"I've been studying aggression for about 30 years," he said, "and I've seen that the most harmful belief that a person can have is that they're superior to others. 'Men are better than women, my race is better than your race, my religion is superior to your religion.' When people believe they're better than other people, they act accordingly."
He and Brummelman wrote in this paper: "Narcissistic individuals feel superior to others, fantasise about personal successes, and believe they deserve special treatment. When they feel humiliated, they often lash out aggressively or even violently."
So can anything be done to halt this process? Brummelman said yes, both during the ages of 7-12, when the sentiment develops, and later. "Perhaps we can develop a way to help parents convey affection and appreciation for a child without necessarily putting a child on a pedestal, without telling the child he is better than others," he said.