Twenge, J. M., Konrath, S., Foster, J. D., Keith Campbell, W., &Bushman, B. J. (2008). Egos inflating over time: A cross‐temporal meta‐analysis of the Narcissistic Personality Inventory.
ABSTRACT A cross‐temporal meta‐analysis found that narcissism levels have risen over the generations in 85 samples of American college students who completed the 40‐item forced‐choice Narcissistic Personality Inventory (NPI) between 1979 and 2006 (total n=16,475). Mean narcissism scores were significantly correlated with year of data collection when weighted by sample size (β=.53, p<.001). Since 1982, NPI scores have increased 0.33 standard deviation. Thus, almost two‐thirds ...