Does a hush really pass over a crowded room 20 minutes after the hour?

group waiting by clock
This group looks pretty quiet and it's not 20 minutes after the hour. Does a hush really pass over a crowded room 20 minutes after the hour?
Š nycshooter

It happens all the time: You're talking with a group of people when, with no apparent warning, everyone stops talking. The hush that follows is known, depending on the nature of the conversation, as an awkward silence, dead air 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.

There are many explanations given for this effect, ranging from the completely superstitious to the vaguely scientific. Let's start with the superstitious. One superstition says that any sudden silence at 20 minutes after the hour occurs because angels are singing and all mortal beings, either consciously or unconsciously, stop to listen to the heavenly chorus. Another superstition asserts that crowds fall silent at 20 minutes after the hour as some sort of residual recognition of Abraham Lincoln's death, which occurred at 7:20 on April 15, 1865. There is no proof to support these superstitions, and, if anything, they raise a number of questions. Why do angels sing at exactly 20 minutes after the hour, or, if they are singing all the time, why do we stop to listen once an hour? Why don't we listen all the time? Similarly, why would a silence today be linked to Lincoln's final labored breath? Did the crowd gathered around Lincoln's deathbed fall silent that long-ago spring morning? If so, why would crowds fall silent at 20 minutes after every hour? Why not at exactly 7:20? And why not at 7:20 on April 15?


Others take a more scientific tack to the silence of "20 minutes after the hour." Members of this group offer up the protection postulate, which says that humans lapse into silence so that they can listen for danger in the manner of their prehistoric ancestors. As soon as we're satisfied danger isn't lurking nearby, we resume talking. It's certainly a reasonable notion, bringing to mind Carl Jung's idea of all humanity sharing an unconscious mind that is the product of ancestral experience.

There is no hard evidence to support Jung's collective unconscious, either, but science has revealed some other interesting clues why silence among members of a group just might be golden.


Communication Within Groups

clock showing 7:20
One superstition asserts that crowds fall silent at 20 minutes after the hour as some sort of residual recognition of Abraham Lincoln's death, which occurred at 7:20 on April 15, 1865.
Š danieljphillips

There's a whole field of social science dedicated to the study of group dynamics and collective behavior. Within this field, researchers investigate various aspects of a group. For example, some researchers study cohesiveness, which refers to all of the forces that cause individuals to remain in groups. Others study participation, which looks at differences not only in the amount of participation among group members, but also the manner, style or tone in which they participate. And, of course, many collective behaviorists study communication within groups. They want to know who does the talking, for how long and how often.

Although this research has revealed much about how crowds behave, it has not shed any light, at least not directly, on the topic of the silence of "20 minutes after the hour." It has provided some indirect evidence that sudden silences in crowds might be little more than superstition. For example, there is a commonly held myth that all crowds are unanimous. Unanimity manifests itself when everyone in a crowd acts in unison. Clark McPhail, author of "The Myth of the Madding Crowd," suggests that such unanimity in crowds rarely happens. According to McPhail's landmark book, people remain stubbornly individual, even when they are surrounded by others. If this is the case, it would seem sudden silences, which would require a crowd to be unanimously silent, would be rare.


But let's accept, just for a moment, that crowds do fall silent on occasion. Let's also put aside the question of whether or not the silences occur at exactly 20 minutes after the hour. Are there physiological or psychological reasons why silence in a group might be necessary? Does silence help the group as a whole or the individuals within the group? Science is able to provide some clues to these questions.

Let's start first with a physiological explanation. Over the years, scientists have tried to understand the physiological mechanisms in rats exposed to a high degree of stress. In one experiment, researchers exposed rats to a buzzer sounding for six out of 30 seconds, seven hours a day for 35 days. The animals in this group suffered from high blood pressure and paced their cages nervously. Animals in the control group, which lived in quiet cages, had markedly lower blood pressure and did not pace nervously.

Now let's consider a 2005 study from the University of London that aimed to understand the psychological impact noise might have. In this experiment, researchers studied 2,800 children in 89 schools. Some of the schools were located next to airports, while others were not. Children exposed to high levels of aircraft noise had much poorer reading skills than children in quieter neighborhoods. Researchers used the term "cognitive fatigue" to describe why reading skills might suffer in children living in noisy environments. In such conditions, their long-term memory is interrupted, and they simply stop paying attention.

What do these studies suggest about sudden silences? Perhaps silence in a crowd is a protective mechanism. It keeps the blood pressure of individuals low and reduces cognitive fatigue. This maintains the health of each member of the group, which, ultimately, maintains the health of the group itself.


Lots More Information

Related HowStuffWorks Articles

  • Childs, Craig. "Perfect Quiet." Miller-McCune. June 25, 2009. (July 20, 2009)
  • Martinez, Al. "No grace, no civility, just anger." Los Angeles Times. July 9, 2004. (July 20, 2009)
  • PsyBlog. "7 Myths of Crowd Psychology." (July 20, 2009)
  • "Sudden Silences." (July 20, 2009)