Ever see someone (even yourself) walking the same as someone
  else, or picking up your fork at the same time and chewing the
  same, or finishing each others sentences? Yeah - it's this. It's
  also the basis of norms. The systems are self-organizing, once
  they get started.[1]socflows

References

  Visible links
  1. http://icopiedyou.com/wp-content/uploads/2015/07/socflows.gif