In this chapter, we discuss work that compares cognition and behavior in humans to other species. We explore how these comparisons can generate insights into selection pressures that have shaped cognitive systems across diverse social and ecological contexts, as well as aspects of cognition that are unique to humans versus shared with other species. We first review two kinds of methodological approaches for human-animal comparisons: down-linkage and up-linkage studies. We highlight the utility of these different approaches by using research on inequity aversion as an illustrative example of both. In the next section, we explore top-down and bottom-up motivations driving human-animal comparisons. Here we focus on studies of punishment in humans and animals as a case study of a topic that has fruitfully compared humans to other species in both directions. We end by summarizing the insights that these kinds of comparisons can generate and make suggestions for future work.