We are not in the savanna anymore

The savanna theory of happiness posits that the human brain is designed for and adapted to the conditions of the ancestral environment, not necessarily the current environment, and is therefore predisposed to perceive and respond to the current environment as if it were the ancestral environment. We may have difficulty comprehending and dealing with entities and situations that did not exist in the ancestral environment, roughly the African savanna during the Pleistocene Epoch.

The Savanna Principle is a term coined by Satoshi Kanazawa in 2004. It can explain why, for example, nearly half the players of one-shot Prisoner’s Dilemma games make the theoretically irrational choice to cooperate with their partner. The game models a situation that did not exist in the ancestral environment, and the human brain has difficulty comprehending completely anonymous social exchange and absolutely no possibility of knowing future interactions.

Recent theoretical developments suggest that general intelligence, far from being domain-general, might have evolved as a psychological adaptation to solve evolutionarily novel problems. This suggests that the evolutionary constraints on the human brain proposed by the Savanna Principle may be stronger among less intelligent individuals. More intelligent individuals are more likely to make the theoretically rational choice to defect in one-shot Prisoner’s Dilemma games, because they would be better able to comprehend the evolutionarily novel situations of complete anonymity and absolutely no possibility of knowing future interactions and make the rational decision to defect. In contrast, less intelligent individuals may have greater difficulty comprehending such novel situations and, as a result, make the theoretically irrational (albeit evolutionarily rational) decision to cooperate.

In a paper published last year(1), Norman P. Li and Satoshi Kanazawa focus on two factors that characterise basic differences in the social landscape of ancestral versus modern environments and thus might affect life satisfaction: population density and friendships. The two following charts are self-explanatory:

Interaction effect between county population density and intelligence on life satisfaction.
Interaction effect between frequency of socialization with friends and intelligence on life satisfaction.

In particular, the effect of friendships on life satisfaction may be particularly stronger among less intelligent individuals, who are likely less able to adapt to evolutionarily novel circumstances such as a dearth of close friends.


(1) Li, Norman P., and Satoshi Kanazawa. 2016. ‘Country Roads, Take Me Home… to My Friends: How Intelligence, Population Density, and Friendship Affect Modern Happiness’. British Journal of Psychology (London, England: 1953) 107 (4): 675–97. https://doi.org/10.1111/bjop.12181.

Featured Image: Savana painting — African SPEED painting


    • Thank you very much Marc for your comment and the clarification. I am not qualified to discuss where our ancestors lived, so I assume you are right (I will read your reference). However, I think the authors of the paper quoted here are using the term savanna simply as a metaphor and I did the same with the title paraphrasing Wizard of Oz’s “we are not in Kansas anymore”. Satoshi is an evolutionary psychologist, and I do not think the savanna or the waterside are key for his argument.

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