Social Psychology, Vol 55(6), 2024, 306-315; doi:10.1027/1864-9335/a000568
Cooperation is critical for successfully functioning close relationships, workplaces, local communities, and civil society. In this research, we examined whether people’s cooperativeness is fostered by their acting nicely in everyday social interactions. In cross-sectional correlational Study 1 involving an online sample (N = 463), we found that the propensity for niceness was positively correlated with cooperativeness, and this relationship was partially explained by social connectedness. Next, in a field multilevel experiment involving students working in teams (N = 164), we confirmed the causal positive effect of acting nicely toward teammates on teamwork satisfaction and attitudes toward cooperation through a sense of connectedness. Our findings could be used across various domains of life to enhance cooperation by promoting and training niceness. (PsycInfo Database Record (c) 2025 APA, all rights reserved)