Straight from the Wikipedia article: Pinker identifies five "historical forces" that have favored "our peaceable motives" and "have driven the multiple decline

Straight from the Wikipedia article: Pinker identifies five "historical forces" that have favored "our peaceable motives" and "have driven the multiple declines in violence." They are: The Leviathan – the rise of the modern nation-state and judiciary "with a monopoly on the legitimate use of force," which "can defuse the [individual] temptation of exploitative attack, inhibit the impulse for revenge, and circumvent ... self-serving biases." Commerce – the rise of "technological progress [allowing] the exchange of goods and services over longer distances and larger groups of trading partners," so that "other people become more valuable alive than dead" and "are less likely to become targets of demonization and dehumanization." Feminization – increasing respect for "the interests and values of women." Cosmopolitanism – the rise of forces such as literacy, mobility, and mass media, which "can prompt people to take the perspectives of people unlike themselves and to expand their circle of sympathy to embrace them." The Escalator of Reason – an "intensifying application of knowledge and rationality to human affairs," which "can force people to recognize the futility of cycles of violence, to ramp down the privileging of their own interests over others', and to reframe violence as a problem to be solved rather than a contest to be won."