Aggressive behavior not only negatively affects an individual’s psycho-social adaptation but also undermines social harmony and stability. This study investigated the relationship between perceived crowdedness and aggression, examining the mediating role of relative deprivation and the moderating effects of upward social comparison and connectedness to nature based on the general strain theory and the I³ model. A cross-sectional design was employed, involving 848 participants (524 females, 61.8%) aged 20–75 (M = 33.15, SD = 6.83) in China. Structural equation modeling and bootstrapping procedures were used to test the hypothesized moderated mediation model. The results indicated that perceived crowdedness and upward social comparison positively predicted aggressive behavior, whereas connectedness to nature negatively predicted it. Relative deprivation mediated the relationship between perceived crowdedness and aggressive behavior. Only upward social comparison moderated the relationship between perceived crowdedness and relative deprivation, and connectedness to nature showed a marginally significant moderating effect on the relationship between perceived crowdedness and aggressive behavior. Unexpected trends are discussed, along with directions for future research.

As the aging population expands, the proportion of older adults facing physical health challenges is expected to increase substantially. A fundamental question arises as to whether healthy community environment can effectively enhance the physical health of the elderly. This study, based on the 2021 Chinese General Social Survey, included a total of 696 participants aged 65 and above. Our study aimed to investigate the impact of healthy environment, healthy service, and healthy neighborhood on physical health of the elderly, as well as the mediating effects of sleep quality in these relationships. The results are as follows: (1) There were significant positive correlations between healthy environment, healthy service, healthy neighborhood, and sleep quality in pairwise relationships. There was also a significant positive correlation between healthy environment and objective physical health. Similarly, healthy services and healthy neighborhood each had significant positive correlations with subjective physical health, and sleep quality exhibited significant positive correlations with both subjective and objective physical health. (2) After controlling for variables such as gender, age, and perceived socioeconomic status, sleep quality played a mediating role in the relationship between the healthy community geographical environment and physical health of the elderly. The research findings provide empirical evidence for enhancing the physical health of the elderly from the perspective of building a healthy community.