Acult claimed to have received messages from a group of aliens. according to this cult, the world was going to be destroyed on dec 21. in preparation, group members sold their worldly belongings and quit their jobs. researcher leon festinger and stanley schachter were curious to see how group members would react when the world didn't end on doomsday. they thought the gap between what the group members had done and their belief would produce

cognitive dissonance                  

Explanation:

        In the world of psychology, a cognitive dissonance occurs when the person have two or more opposed or contradictory ideas, beliefs, or values, and he participates in the action which goes against his own contradictory beliefs and thoughts, and he experiences some psychological stress because of that.

        In the context, people of the planet earth prepared themselves for the doomsday by quiting their jobs and selling their worldly belongings. Now a group of researchers will study how the people will behave and react according to their cognitive dissonance when the earth would not end on the doomsday as people thought and their reactions to their steps that they have taken for the doomsday.

Hence the answer is -- cognitive dissonance      

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