Taking another person’s perspective is widely presumed to increase interpersonal understanding. Very few experiments, however, have actually tested whether perspective taking increases accuracy when predicting another person’s thoughts, feelings, attitudes, or other mental states. Those that do yield inconsistent results, or they confound accuracy with egocentrism. Here we report 25 experiments testing whether being instructed to adopt another person’s perspective increases interpersonal insight. These experiments include a wide range of accuracy tests that disentangle egocentrism and accuracy, such as predicting another person’s emotions from facial expressions and body postures, predicting fake versus genuine smiles, predicting when a person is lying or telling the truth, and predicting a spouse’s activity preferences and consumer attitudes. Although a large majority of pretest participants believed that perspective taking would systematically increase accuracy on these tasks, we failed to find any consistent evidence that it actually did so. If anything, perspective taking decreased accuracy overall while occasionally increasing confidence in judgment. Perspective taking reduced egocentric biases, but the information used in its place was not systematically more accurate. A final experiment confirmed that getting another person’s perspective directly, through conversation, increased accuracy but that perspective taking did not. Increasing interpersonal accuracy seems to require gaining new information rather than utilizing existing knowledge about another person. Understanding the mind of another person is therefore enabled by getting perspective, not simply taking perspective.