I've been reading Franz De Waal's Primates and Philosophers. De Waal is clear that the answer is an emphatic "yes" from the evidence he has gathered from is extensive studies of primates. Besides this direct evidence, the indirect evolutionary evidence he presents is quite convincing to me. De Waal is a wonderful writer. Highly recommended, with discussions by Robert Wright, Christine Korsgaard, Philip Kitcher, and Peter Singer as a bonus.