"[Hu]man[s]... have imagined... [themselves] to be more unlike other mammals than [t]he[y] really... [are], so when human behavior has shown these same characteristics, various other explanations have been put forth which have obscured the significance of population pressure itself. In the twentieth century, with human numbers enlarged and resource draw­down becoming significant, [hu]man[kind] went to war. [T]he[y] rioted in the streets. [T]he[y] committed more... crimes of violence. [...] [Their] political atti­tudes polarized and [t]he[y] created totalitarian governments, some of which gave license to sadistic tendencies. A generation gap widened and deepened. In spite of earnest efforts by humane activists to inhibit racism and to rectify economic inequality, disparities between people remained and animosities became more virulent. Standards of de­cency in behavior toward others and expectations of considerate self-­restraint were eroded and degraded in many places."