One of the most baffling things about the adherents of some beliefs is proof that they are wrong only confirms members of the group in their belief that they are right.

The Jehovah’s Witnesses predicted the day of God’s wrath would come in 1918. This unfulfilled prophecy was followed by a belief in the resurrection of figures from the Bible in 1925. The patriarchs did not reappear. The Witnesses believed the world would end in 1975. Plainly, it did not. The fact they were completely and repeatedly wrong wrong did not lead to the end of their movement.

More recently, Harold Camping of the evangelical broadcasting organisation Family Radio predicted the end of the world on September 6th 1994, then September 29th, then October 2nd. Being wrong did not dissuade him from his views, he changed the date to 21st May 2011, then 21st October 2011. After so many failures, after Camping’s death, the organisation disowned Camping’s teaching, moving instead to the equally entrenched fundamentalist doctrine of creationism.

Social psychologist Leon Festinger developed the idea of cognitive dissonance to describe the stress felt by those whose beliefs, ideas and values are not consistent with their external experience. Festinger believed that some people would resolve the dissonance by blindly believing what they wanted to believe.

In his book When Prophecy Fails, Festinger tells of a group led by Dorothy Martin in Chicago in 1954. Dorothy Martin claimed to receive messages from aliens through automatic writing and told her followers that a UFO would save then from a flood that would destroy the world at dawn on 21st December that year. Festinger describes the hours before the expected end:

December 20. The group expects a visitor from outer space to call upon them at midnight and to escort them to a waiting spacecraft. As instructed, the group goes to great lengths to remove all metallic items from their persons. As midnight approaches, zippers, bra straps, and other objects are discarded. The group waits.

12:05 am, December 21. No visitor. Someone in the group notices that another clock in the room shows 11:55. The group agrees that it is not yet midnight.

12:10 am. The second clock strikes midnight. Still no visitor. The group sits in stunned silence. The cataclysm itself is no more than seven hours away.

4:00 am. The group has been sitting in stunned silence. A few attempts at finding explanations have failed. Martin begins to cry.

4:45 am. Another message by automatic writing is sent to Martin. It states, in effect, that the God of Earth has decided to spare the planet from destruction. The cataclysm has been called off: “The little group, sitting all night long, had spread so much light that God had saved the world from destruction.”

Afternoon, December 21. Newspapers are called; interviews are sought

Extraordinary as it seems, the failure of the prophecy had strengthened the belief of the group members.

Festinger’s findings seem a way of understanding the paradox of the persistence of many groups, not just religious ones.