Want to know how motivated somebody is to act, and what's that person's most likely course of action? As good as any way of predicting imminent behavior -- and certainly better than words alone -- is a tool that's my specialty, facial coding, the scientific reading of people's emotional state through the analysis of their facial muscle activity. That's because every emotion felt has its own meaning or significance, and drives a person's behavior accordingly. 

The tool was originated by Charles Darwin, refined by Dr. Paul Ekman, the inspiration for the "Lie to Me" series on Fox, and is universal in nature. Indeed, as Darwin first discoverd and has been verified in half a dozen studies since then, even people born blind reveals their emotions through the same muscle movement patterns that you and I do because facial expressions aren't learned or socialized; they're innate and intuitive.

Speaking of universality, let's use facial coding to turn our attention to international affairs and, specifically, current and recent events in the Middle East. In this case, in contemplating why one (former) leader, Egypt's Mubarak, readily lost power and why another one, Libya's Qaddafi, is at least to this point still hanging on, facial coding reveals not only the likely short-term behavior patterns but also, over time, the character or personality traits of an individual.

On first blush, it's Egypt's former leader, Mubarak, who should still be in power instead of Libya's Qaddafi. After all, the armed forces under Mubarak's command dwarfed anything Qaddafi can put together. But aside from other socio-economic factors, there's another set of key reasons why Qaddafi still rules and Mubarak doesn't -- and that set of three reasons have to do with the emotional dynamics of leadership amid turmoil, of which Qaddafi is a comparative genius.

For starters, let's consider the matter of vitality. Across the Arab world, what's the specter? It's of aged, long-tenured rulers trying to hold on against a sea of young people. Given that backdrop, displaying vitality - the literal emotional energy required to offset the natural energy of youth - is a prerequisite. Qaddafi shows it; his face is alive with emotion, emotion that reveals his resiliency, his determination to hold onto power. He's animated, combative, the antithesis of a dead man walking.

In contrast, Mubarak came across as stunned into emotive silence by the sudden turn of events. There he stood, talking on national television as if he were comatose. Showing vitality is crucial because people wish to ally themselves with those who are full of energy, or at least the promise of continued spoils. Mubarek came across as a tired, defeated man, lacking the resiliency required to continue to wield power.

Second, not only does Qaddafi work hard to shower vitality, he conveys the threat of revenge. In Mubarak's case, how did he come across in addressing his people? Why, the anger Mubarak showed was of the concerned, annoyed, even scolding variety. As to merely, and inadvertently, reinforce the age gap between him and the young protesters, Mubarak came across as the scolding parent. And a feeble one at that. Yes, his eyebrows lowered in a sign of concern -- but that's the lowest grade version of anger.

Not so with Qaddafi, whose facial expressions of anger aren't merely the slight pursing of the lips (annoyance) or of eyebrows lowered in a display of concern. In Qaddafi's case, almost from the start, and certainly with gathering strength, Qaddafi's way of expressing negativity - and hostility to the protesters, and rebels - has been in the way his eyes narrow in anger, and his upper lip curls in disgust. 

Now that move of narrowing the eyes, I call the "snake eyes" look. And that fits. Because a snake coils before it strikes, and that's the key to the signals Qaddafi is intuitively sending to Libya's citizens. Emotionally, he's saying in effect: I'll exact terrible revenge on any who oppose me. Just you watch and wait. And for anybody who's hesitating to join the rebellion, or stay active in it, that's an ominous message that I believe helped turn the tide of momentum in Qaddafi's favor at least until the recent military intervention by the American, Frence and British armed forces, notably their air forces.

I say so because the exact dynamic Qaddafi sought was to use displays to anger to instill fear, a paralyzing emotion, among the wavering, loyalty-uncertain members of Libyan society. Snake-eye displays of anger combined with menacing words has been Qaddafi's way of communicating his lethal power, the venom, that he can unleash on those who oppose him.

Finally, third, Qaddafi has a sense of drama about himself that serves him well in a way Mubarak seemed clueless about. Think of how Mubarak handled himself, after all. There he stood behind the podium, generally with nobody else around him - isolated - as if he were in a sensory deprivation chamber. He hardly seemed to be a national leader; you must have followers to be a leader.

Qaddafi's different. In Qaddafi's case, he's out in public. He's on a rooftop, raging by bullhorn to supporters below him. Or he's in a tent, talking to the people gathered in front of him and around him. He's not isolated. And he's not wearing a Western businessman's suit, which Murbarak did, only reinforcing the impression that he was a man cut off from his own country and its traditions. 

Instead, Qaddafi is careful to be on display fairly spontaneously talking to people, interacting with them, and in part it's that spontaneity that also matters because the mostly methodical Murbarak was, frankly, an easier opponent to strategize against because you can more easily anticipated what he'll do next.

Now I'm hardly endorsing Qaddafi. That's not my point. It's that should you wonder how Qaddafi could still be hanging on, while Mubarak's already been swept down the river of history, I've tried to lay out part of the reason why Qaddafi remains a force that France, Great Britain, the U.S. and others will still have to tangle with in the days ahead. One leader, when he says he'll fight to the death, we believe. The other already looked emotionally and politically deceased. 

As other leaders in Arab countries like Yemen, Bahrain, Jordan and Syria try to contain the rebellions in their own countries, they would do well to heed the signals Qaddafi showed and, for their own sake, avoid the emotional clues Murbarak unwittingly gave his fellow citizens.

Dan Hill is a facial coding expert. He is president of Sensory Logic.