The article discusses how altruism in animals can be explained by group selection, where behaviors that benefit the group can evolve. Researchers showed that group selection can influence evolution, especially when Hamilton's rule applies. They also found that group selection drove major evolutionary transitions. By extending Hamilton's rule, they replaced genealogical relatedness with a new concept to explain altruistic behaviors. Overall, cooperation and altruism can evolve through various selection processes, including kin selection and selection for the common good.