you can test it yourself without any words being needed. go with a couple of mates into a waiting room somewhere. wait until theyre settled. all three of your stand up randomly for no reason and stay there. watch the other person look around strangely and stand up with you. same thing goes with a bunch of people looking randomly at the same place, youll find other people will join in. ask them 'woah can you see that?' see how many people answer 'omg yeah!'