Steven Strogatz : The science of sync

Steven Strogatz at TED 2004
The science of sync  (transcript)
Summary
I thought that "Sync" is something that occurs by chance simultaneously but it's a good thing. For example, when I think that I want to go somewhere, my friends also think of the same place and we meet there, we don't call each other, though.
I like such situations somehow and I'm interested in thinking about unconscious human behavior.
However, now I understand that synchronizing, I thought for a good thing, is that there is a thought that, for example, I want to go somewhere or the speaker wants to urge audiences to clap in sync in the article.

In nature, a synchronizing behavior we can see will be to just watch out for predators but in a swarm. 

Just people gathered to cross the bridge, however, they have to protect themselves with skating style because of the waving of the bridge.
Bird and fish are scattering away randomly to protect themselves from predators but they have a rule that is being in a group to protect themselves.

However, the result becomes a big problem that the bridge is failing, we only see a swarm that our skating style walking on the bridge create more bridge wave, though.

In our societies, those must often occur.  When someone knows people's unconscious behaviors, they must be able to control many things. It's interesting but it's scary.

Words in this story
synchronization /noun/ synchrony /noun/ simultaneous action, development, or occurrence.
synchronize /verb/ cause to occur or operate at the same time or rate.
entropy /noun/ measure of level of disorder in a system. amount of unavailable energy in a system.
emergent /adj/ in the process of coming into being or becoming prominent. emerging, developing, rising
unintended /adj/ not planned or meant.