Norms of assertion in the United States, Germany, and Japan

The recent controversy about misinformation has moved a question into the focus of the public eye that has occupied philosophers for decades: Under what conditions is it appropriate to assert a certain claim? When asserting a claim that x, must one know that x? Must x be true? Might it be normatively acceptable to assert whatever one believes? In the largest cross-cultural study to date (total n = 1,091) on the topic, findings from the United States, Germany, and Japan suggest that, in order to claim that x, x need not be known, and it can be false. However, the data show, we do expect considerable epistemic responsibility on the speaker's behalf: In order to appropriately assert a claim, the speaker must have good reasons to believe it.