The NY Times reports. Human evolution relied heavily upon cooperative efforts in the development of agriculture. For example, you will never see two chimpanzees lifting a log together. Furthermore, studies show the idea of fairness may be deeply ingrained our psyche.
"In a recent analysis of five hunter-gatherer populations, Eric Aiden Smith of the University of Washington and his colleagues found the average degree of income equality to be roughly half that seen in the United States, and close to the wealth distribution of Denmark."
So the 23% increase in top executives' pay in the U.S., despite worsening financial situations for most regular workers, might mean that Americans are actually de-evolving.