What is the trigger of shame? The information threat theory holds that shame is an evolved adaptation that is designed to limit the likelihood and costs of others forming negative beliefs about the self. By contrast, attributional theories posit that concerns over others' evaluations are irrelevant to shame. Instead, shame is triggered when a person attributes a negative outcome to their self, rather than to a particular act or circumstance. We conduct a strong test of the information threat hypothesis. In Study 1, participants imagined taking an action that, though morally unimpeachable, could be interpreted unfavorably by others. As predicted by the information threat theory, shame increased with the publicity of this act. In Study 2, participants played a public good game and then learned that the other participants either chose to keep interacting with them (inclusion) or not (exclusion)—ostensibly because of their contributions, but in fact randomly determined by the experimenter. Exclusion increased shame. Under-contribution did not. In fact, even the highest contributors tended to feel shame when excluded. These findings strongly suggest that the true trigger of shame is the prospect or actuality of being devalued by others.