Why care for humanity?

Some of the most pressing challenges facing our planet-such as climate change, biodiversity loss, warfare and extreme poverty-require social cohesion and prosocial action on a global scale. How can this be achieved? Previous research suggests that identity fusion-a strong form of group cohesion motivating prosocial action-results from perceptions of shared personally transformative experiences or of common biological essence. Here, we present results from two studies with United States samples exploring each pathway to identity fusion on a global scale. Study 1 focused on globally shared motherhood experiences and found that US mothers were more fused with women around the world if they shared motherhood experiences with them, which was also reflected in money allocation behaviour. Study 2 showed that exposure to a talk about globally shared biology increased fusion with humanity at large, Americans and the extended family suggesting that fusion with humanity does not need to weaken fusion with nation or extended family. We discuss implications of our results for future research on bonding with humanity at large and for addressing collective action problems on a global scale.