The Effecpiness and Happiness Growth During Middle and High School Students on Grit and Sleep Quality

Abstract

This study examines the development of happiness (initial level) and happiness growth (rate of change) over time during the middle and high school years (from 7th grade to 10th grade) and investigates the effects of happiness (initial level) and happiness growth (rate of change) on grit (consistency of interest, persistence of effort) and sleep quality. Using data from the "Korean Children and Youth Panel Survey 2018," unconditional and conditional second-order latent growth models were tested via structural equation modeling. The findings are as follows. First, the average initial level of happiness was significant at the starting point (7th grade), and the average trajectory of happiness growth (rate of change) showed a decline over time. Second, the variances of both the initial level of happiness and happiness growth were significant. Third, greater initial levels of happiness and steeper growth trajectories of happiness from 7th to 10th grade were significantly associated with higher levels of consistency of interest and persistence of effort in 10th grade. Fourth, higher initial happiness levels and greater growth in happiness over this period were significantly linked to better sleep quality in 10th grade. These findings indicate that while the average happiness trajectory of middle and high school students tends to decrease, individual trajectories vary. Given the positive influence of initial happiness and happiness growth on psychological resources (grit) and physical resources (sleep quality), these results suggest the need for educational support to foster happiness and happiness growth in middle and high school students.