With warnings of the coming tide came the promise that she and the other believers would be rescued by the Guardians before the flood came, on December 17. One of her most ardent supporters was Charles Laughead, a staff doctor at Michigan State in East Lansing, Michigan, who was asked to resign his position for teaching his beliefs and upsetting students. (In a Chicago Tribune article from the time, he maintained that he was fired.)

But a few of the other believers who would end up singing carols with Martin on Christmas Eve weren’t actually believers at all. They were scientists.

A team of researchers from the University of Minnesota studying social movements had learned of Martin earlier that year, and considered her and her followers a perfect field study. They began spending time with Martin in October, eventually earning her confidence, and watched how she and her followers dealt with disappointment over the next several months as their predictions repeatedly failed to pan out.

Three of the Minnesota researchers, Leon Festinger, Henry Riecken, and Stanley Schachter, recounted the believers’ story in detail in their book When Prophecy Fails, published nearly 60 years ago on January 1, 1956. The experiences of Martin and the other believers were influential on Festinger’s theory of cognitive dissonance.

According to the book, the spacemen’s arrival was originally scheduled for 4 o’clock on December 17. The believers removed all the metal from their bodies, “an act considered essential before one might safely board a saucer,” the authors write, and went out into Martin’s backyard, scanning the skies. Ten minutes went by, and then Martin, who is given the pseudonym Marian Keech in the book, “abruptly … returned to the living room.” Others trickled away, and the last believers went back inside by 5:30.

In the house, they discussed what went wrong, eventually landing on the explanation that it must have just been a practice session. “The saucers would indeed land when the time was ripe, but everyone had to be well trained, ‘well-drilled actors,’ so that when the real time arrived, things would go smoothly,” the book reads. “The spacemen were not testing their faithfulness, but were simply unwilling to leave any possibility that their human allies would make a mistake.”

Faced with evidence that directly contradicted their beliefs, the group experienced cognitive dissonance—two thoughts that are inconsistent. This is uncomfortable, and the natural instinct is to try to make it go away. People can do that in a few different ways: by trying to forget about the dissonant things, by changing their minds, or by looking for new information that gets rid of the contradiction.

Sometimes this can mean, as the alien-less Christmas demonstrated, people can react to evidence against their beliefs by leaning in to those beliefs even more. At midnight, when the 17th became the 18th, Martin claimed to receive a message that the flying saucer was coming right then and everybody had to get on board or be left behind. For her followers, this new message served as confirmation that they had been right to believe. They scrambled outside, being sure to remove any remaining metal from their persons.