The "world-will-end-on-june-7" group got together on june 7 to pray as the world ended. the next day, the world had not ended. the leader of the group said, "our prayers saved the world." what process was responsible for the attitude change

The process was cognitive dissonance

This is the process where people have inconsistent thoughts and behave weirdly in their decision making. In this case, they correlated the prevention of the destruction of earth with their prayer, even though it had nothing to do with it. This is opposite of their previous statement which said that the world would end on that date.