Persistent inhumanity persuades us human problems are genetic, an inheritance from cavemen forefathers. We see forces like nationalism as intrinsic in the nature of the beast, beyond our power to control.
We do not see collective behavior as "psychological", but if perceptions create behavior, new perceptions bring different behavior. Changing the collective image to something more positive means breaking with the collective past (history) to become a species that behaves differently.Collective image psychology sees our perception of "human nature" as self fulfilling. To make our prophecy true, we become the species we think we are.
"Collective perceptions", ideas we hold with others, are favored belief systems. We are reassured when we believe what others believe, but the number who believe has nothing to do with the validity of the belief. Most of what we believe is unverifiable no matter how many believe it. My individual belief Collective Image Psychology describes how collective behavior works is as "true" as your collective belief it does not.