1.   Although single virtual actors can help train individuals, some organizations are using virtual humans in groups to try to model crowd psychology.

2.   As a result, Leung said, Hong Kong is a place where crowd psychology is particularly apparent.

3.   Financial bubbles, those dangerous combinations of crowd psychology and alluring, wispy investment offers, have a long and painful past.

4.   He said it seemed to be more a function of crowd psychology.