If you look at national economies today, for example, the American economy, the European economy, the Indians, the Chinese, we're all tied together. If one of them sinks, the rest are going to sink with them and if one floats, the rest are lifted up. I find that very interesting.

If one bird foraging in a flock on the ground suddenly takes off, all other birds will take off immediately after, before they even know what's going on. The one who stays behind may be prey.

If there is any form of contagion that is adaptive, it is the immediate response to the fear of others. If others are fearful, there may be good reason for you to be fearful too.

Frans de Waal Quotes