What is savanna principle in Psychology?

This refers to the hypothesis that the human brain is adapted primarily to the conditions in which human ancestors survived once upon a time rather than to the modern age. The term was coined by American evolutionary psychologist Satoshi Kanazawa in an academic article published in 2004 to state that the human brain may be adapted to the time when human ancestors lived in the African savannas. The Savanna principle has been used to explain why a lot of human behaviour in the modern age seems irrational. Since the modern age is relatively recent in evolutionary terms, the human brain may not have evolved sufficiently to deal with the modern environment.

Source: The Hindu, 29/11/2018