One of the precursors in both settings that enabled the social psychological behavior of Hitler and the Khmer Rouge to take hold was the complexity and intricacy to suffering in their respective societies. Both forms of social psychology sought to reduce the complexity of suffering to concepts that scapegoated a particular group for the problems that existed in their societies. In both social psychological experiments, complexity, intricacy, and a sense of the unclear were put aside for simplistic binary opposition that paved the way for atrocities
For the Khmer Rouge in Cambodia, the economic and political challenges that the Vietnam War triggered was reduced to a simplistic blaming of Lon Nol as the cause of all that was wrong. The Khmer Rouge did not take an introspective approach to the problems Cambodia faced. They simply blamed the current system as the reason why all was wrong. As they preached to farmers that urban intellectuals were at the cause of all that ailed Cambodia, the social psychological element of simplicity in the face of intricacy was employed. The Khmer Rouge understood that in making things simple, identifying a cause and an agent of blame, a narrative can be presented which can be easily digested. This enabled the Khmer Rouge to be depicted as agents of liberation and hope and the Status Quo as agents of destruction and brutality.
Hitler embraced this same social psychological approach. The economic and political challenges of Weimar were complex as so much of the world found themselves in the same condition. Hitler was able to appeal to the German public in blaming outsiders and Jewish people as the cause for the challenging condition. In their desperation and sense of suffering, the German people embraced the simplicity that Hitler offered. In both settings, the social psychological condition in which individuals craved unity and symmetry in any form, even a destructive one, was opted over a vision of nuanced complexity. This becomes part of the condition that enabled both the Khmer Rouge and the Nazis to take power.
The results were mass scale deaths. The social psychological element of simplicity is accepted over every objection. Forces that were deemed as contrary to this spirit of simplistic harmony were eliminated with ease. The social psychological condition of a desire for power, inclusion, and simplicity enabled the worst of atrocities to occur. Hitler was able to perpetrate the Holocaust because Germans and others were able to easily digest the vision offered. The Khmer Rouge were able to kill millions because of the same acceptance. In his work, The Book of Laughter and Forgetting, Milan Kundera describes this social psychological element that seeks simplicity and eventually embraces mass murder:
People have always aspired to an idyll, a garden where nightingales sing, a realm of harmony where the world does not rise up as a stranger against man, nor man against other men, where the world and all its people are molded from a single stock and the fire lighting up the heavens is the fire burning in the hearts of men, where every man is a note in a magnificent Bach fugue and anyone who refuses his note is a mere black dot, useless and meaningless, easily caught and squashed between the fingers like an insect.
It is this condition of a desire to aspire to a "garden where nightingales sing" that serves as the pretext of treating human beings like "an insect."