We have concluded that posting selfies is correlated with narcissism, but how strong is the correlation?
Reference: Correlation between selfie and Narcissism
Table 1 of Fox and Rooney (2015) report this correlation between selfies posted on social networks and narcissim to be r = .19 in a sample of 800 U.S. men, (mean age = 29, SD = 6.5). I.e., the observed correlation was small in a general sense. But in the broader domain of personality-behaviour correlations, .19 is fairly moderate.
Participants’ selfie posting behavior was assessed with one item inquiring how many pictures they had taken of themselves and posted on SNSs in the past week (M = 0.56, SD = 2.33; min = 0, max = 30).
Fox, J., & Rooney, M. C. (2015). The Dark Triad and trait self-objectification as predictors of men’s use and self-presentation behaviors on social networking sites. Personality & Individual Differences, 76, 161-165. doi: 10.1016/j.paid.2014.12.017