Research in cultural evolution has focused on the spread of intuitive or minimally counterintuitive beliefs. However, some very counterintuitive beliefs can also spread successfully, at least in some communities-scientific theories being the most prominent example. We suggest that argumentation could be an important factor in the spread of some very counterintuitive beliefs. A first experiment demonstrates that argumentation enables the spread of the counterintuitive answer to a reasoning problem in large discussion groups, whereas this spread is limited or absent when participants can show their answers to each other but cannot discuss. A series of experiments using the technique of repeated transmission show that, in the case of the counterintuitive belief studied: (a) arguments can help spread this belief without loss; (b) conformist bias does not help spread this belief; and (c) authority or prestige bias play a minimal role in helping spread this belief. Thus, argumentation seems to be necessary and sufficient for the spread of some counterintuitive beliefs.