Decades of research demonstrate the importance of social relationships on well-being in later life. Most of these studies have focused on the impact of close ties on physical and emotional health. This brief, from PRC faculty research associate Karen Fingerman and colleagues, reports on a study that breaks new ground by measuring the association of both close social ties and weak social ties on physical activity and mood. They find that older adults who interact with more weak social ties engage in more physical activity while encounters with close ties improve mood more.