Globalization and Violence

Stephen Pinker shows that violence has declined over time. 
What are the three reasons he gives?  How does each one relate to globalization?  

• "About 15% of people in prestate eras died violently, compared with about 3% of the citizens of the earliest states."  Only about 1.28% of the world died due to violent acts in 2002 which is less than the amount of self-inflicted violence (suicide) which killed 1.53%. 

Also, here is an optional clip of Stephen Pinker @ FP magazine:

the quantitative study of history provides some pleasant surprises. Abominable customs such as human sacrifice, chattel slavery, and torture-executions for victimless crimes have been abolished. Homicide rates have plunged since the Middle Ages, and rates of battle death in armed conflict are at an all-time low. ...many destructive wars have been fought over nebulous claims to national preeminence, including World War I. At the other end of the scale, the single largest motive for homicide on police blotters are "altercation of relatively trivial origin; insult, curse, jostling, etc."

...Perhaps the most extraordinary popular delusion about violence of the past quarter-century is that it is caused by low self-esteem. Self-esteem can be measured, and surveys show that it is the psychopaths, street toughs, bullies, abusive husbands, serial rapists, and hate-crime perpetrators who [have extremely high self-esteem. ...violent people are narcissistic: They think well of themselves ...out of a congenital sense of entitlement. When reality intrudes... they treat the bad news as a personal affront, and its bearer, who is endangering their fragile reputation, as a malicious slanderer.

Violence-prone personality traits are even more consequential when they infect political rulers, because their hang-ups can affect hundreds of millions of people rather than just the unlucky few... Unimaginable amounts of suffering have been caused by [narcissistic] tyrants... The ...American Psychiatric Association defines narcissistic personality disorder as "a pervasive pattern of grandiosity, need for admiration, and a lack of empathy." The trio of symptoms at narcissism's core... fits tyrants to a T. It is most obvious in their vainglorious monuments, hagiographic iconography, and obsequious mass rallies. And... narcissistic rulers leave their mark in more than statuary; they... authorize vast outlays of... rapacious conquest, pharaonic construction projects, or utopian master plans.

Among the pacifying features of democracies is that their leadership-selection procedure penalizes an utter lack of empathy, and their checks and balances limit the damage that a grandiose leader can do.