Pledges are promises to do good things. This study looked at how people decide to make pledges. In an experiment, researchers found that when people see others making pledges, they are more likely to make pledges too. This can encourage a lot of people to make pledges, which is good for society. The way pledges are asked for can also influence people's decisions. Overall, this study shows that when people know others are pledging to do good things, they are more likely to do the same.