Found this nice snippet from the book When Prophecy Fails by Leon Festinger, Henry RIECKEN, Stanley Schachter

Festinger stated that five conditions must be present if someone is to become a more fervent believer after a failure or disconfirmation:

1. A belief must be held with deep conviction and it must have some relevance to action, that is, to what the believer does or how he or she behaves.

2. The person holding the belief must have committed himself to it; that is, for the sake of his belief, he must have taken some important action that is difficult to undo. In general, the more important such actions are, and the more difficult they are to undo, the greater is the individual’s commitment to the belief.

3. The belief must be sufficiently specific and sufficiently concerned with the real world so that events may unequivocally refute the belief.

4. Such undeniable disconfirmatory evidence must occur and must be recognized by the individual holding the belief.

5. The individual believer must have social support. It is unlikely that one isolated believer could withstand the kind of disconfirming evidence that has been specified. If, however, the believer is a member of a group of convinced persons who can support one another, the belief may be maintained and the believers may attempt to proselytize or persuade nonmembers that the belief is correct. (edited)