Happy Tech Lab researchers Kostadin Kushlev and Kibum Moon, who share first authorship, have published a five-wave panel study of 1,966 US adults in Nature Human Behaviour. Moon led the statistical work, fitting Bayesian and frequentist random-intercept cross-lagged panel models that separate a person's own change over time from stable differences between people. Across ten common social technologies reported every three months, the models found little credible evidence that earlier use predicted later life satisfaction. In the reverse direction, increases in life satisfaction predicted only modest increases in (video) calling among select demographic groups. Comparing different people, texting frequency was associated with higher life satisfaction, whereas YouTube and TikTok use were associated with lower life satisfaction. The paper is co-authored with Matt Motyl and Nathanael J. Fast of the University of Southern California and Juliana Schroeder of the University of California, Berkeley. Read the full paper here.