Each generation thinks the next one is more self-centered. A recent study published in Personality and Individual Differences supports this perception: American society has steadily become more egocentric since the nation's beginnings. An overall rise in economic prosperity may play a role in this egotism, according to a different study: people who were young adults during hard times are less narcissistic than those who came of age during economic booms.

To measure trends in egocentrism, researchers at the University of Michigan analyzed the text of State of the Union Addresses from 1790 to 2012. They calculated an “egocentricity index” for each speech by comparing the number of words that indicated self-interest (such as “me,” “we” or “mother”) with the number of words that showed high levels of interest in others (such as “he,” “neighbor” or “friend”). Not only did they find a steady increase in the use of self-interest words in the annual speeches over time, their analysis also revealed that before 1900, the speeches almost always used more other-interest words. After 1920, nearly every speech used more self-interest words.

To see if a president's speeches reflect egotism in American society at large, the team compared its results to studies of egotism in other cultural products, such as 20th-century books and songs. The researchers found rising egotism across the board. “This result tells me it's bigger than just a president,” says Sara Konrath, a co-author of the paper and a professor at the Institute for Social Research at Michigan.

In a related but independent study published in July in Psychological Science, Emily Bianchi, a professor at Emory University's Goizueta Business School, looked at how the state of the nation's economy affected individual levels of narcissism. Bianchi used two types of personality tests to measure the narcissism of 32,632 participants aged 18 to 83. She found that people who were between 18 and 25 years old during hard economic times, as measured by unemployment rates, were less narcissistic later in life than those who came of age during economic booms. The same was not true for other age groups. Bianchi reasons that the difference exists because early adulthood is formative. Inexperienced employees are the most vulnerable during a recession; how much one struggles to establish a professional identity has a lasting impact.

In the final part of her study, Bianchi looked at CEO compensation relative to other executives. “It's a well-validated indicator of narcissism,” Bianchi explains. “A CEO has control over how much the second most senior person gets paid.” Using data from 2,095 CEOs, she found that those who were emerging adults during economic booms had a compensation that was 2.3 times higher than their second top executive, versus a difference of 1.7 for those who came of age in less prosperous times. As such, she believes the recent recession of 2008 and 2009 and its lasting effects on the job market will probably temper narcissistic tendencies in today's young adults—a dip in an overall rising trend.