Slapout,
The author's first book was on emotional intelligence (in fact that was the name) - I have not read that one, but he spends some time going over it where needed. This idea of a contagion is based on how mirror neurons work. The author also breaks down how the senses tie in "low road" and "high road" emotive cognition. Empathy it seems has several definitions.

Consider how panic works. It is primarily a base or low road response with little rationalizing behind it. It seems our brains have evolved to pick up on warnings and other emotions - we are somewhat wired for survival. The author also points to experimentation which points to us being wired for social activity. Combining the two means that strong emotions may trigger instincts - the whole "flight or fight" pitch. The emotion of the situation dampens rational thought - particularly when the object at risk might be yours or your family's life. Further, he suggests that ay rationalizing (high road functions) that occurs is subject to mutation by the "low road".

Part of this is the type of chemical reactions that occur. Remember the info that somebody was recently experimenting with fear inhibitors for military use. Anyway this is not a technology pitch

I agree there has to be something to the idea. Something happens when you have cult murders, infanticide, tribal genocide, riots, and indiscriminate killing like that of Baghdad last year.

So how does understanding help? The causal relationship does not disappear quickly. You can't frontal lobotomize populations. What it might help us do though is anticipate reactions to events or guage how crowd behavior goes South. This might be applicable to population control type tasks or operations, or deconstructing where things went bad. It might also be useful be useful in looking at constructing ROE measure that keep someting from going critical.

Is Marc T around - I hate to always reach for Marc to provide us info on social sciences, but we're still looking for some other scientists to fill the roles of us knuckle draggers and Serpicos