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You're talking with a group of people when, with no apparent warning, everyone stops talking. Most people just consider it an awkward silence or a pregnant pause. But a few people refer to this inexplicable quiet time as the silence of "20 minutes after the hour." They believe that the hush falling over a crowd -- even a large crowd, such as one gathered for a sporting event -- occurs exactly 20 minutes after the hour.

What causes a hush in a crowded room? Learn whether science backs up the idea that there's a reason for a hush falling over a crowded room at certain times.

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