The time horizon that is practically relevant to humans has been stretched to incredible lengths

From The delusion of political violence by Lionel Page.  The subheading is Our fantasies about violence are an evolutionary mismatch.  

One of the key differences between our ancestral past and our present is the length of our time horizon when making decisions. It is much, much longer now. Think about our ancestors, who for eons lived in small communities, hunting and gathering food. For sure, they understood that life lasted decades. However, the time horizon practically relevant for them was relatively short.

In such an environment, for most practical decisions, time horizons were anchored in seasonal and annual cycles. The human brain, designed to navigate successfully this type of decision situation, has been thrown into a very foreign world: the setting of modern large-scale urban societies. In this world, the time horizon that is practically relevant to humans has been stretched to incredible lengths. One mechanical reason is that our life expectancy has increased substantially. It is now around 80 in most Western countries.

[snip]

 As the time horizon gets longer, people are more and more able to approximate full cooperation.