Final answer:
The attitude change in the World-Will-End-on-June-7 group is explained by cognitive dissonance, which occurs when people alter their beliefs to reduce discomfort from holding contradictory cognitions.
Step-by-step explanation:
The attitude change described in the scenario where members of the World-Will-End-on-June-7 group believe that their prayers saved the world, after the world did not end as they predicted, is best explained by cognitive dissonance.
Cognitive dissonance is a psychological phenomenon that occurs when a person holds contradictory beliefs, attitudes, or thoughts (known as cognitions). In the face of undeniable evidence that the world did not end, the group members experience dissonance because their prediction was incorrect. To resolve this dissonance, they adjust their beliefs, crediting their prayers for the world's continuation. This allows them to maintain their previously held belief in the power of their actions without admitting they were wrong about the prediction.
Other processes such as operant conditioning, classical conditioning, and positive reinforcement do not adequately describe the change in attitude in this context. These involve the strengthening or weakening of a behaviour by its consequences, whereas cognitive dissonance involves a change in belief to reduce psychological discomfort.