Kanazawa S. (2004) The Savannah Principle

Kanazawa, Satoshi (2004) “The Savanna Principle”, Managerial and Decision Economics, 25/1, 41-54.



Models designed and used by microeconomists commonly fail to predict actual human behaviours (p.41). The author proposes to use Evolutionary Psychology (EP) to overcome these shortfalls. Unlike Evolutionary Economics which deals mostly with the evolution of strategies and organizations, EP uses the substance of Darwinism, instead of merely mimicking its principles.

“EP seeks to discover universal human nature, which is a collection of domain-specific psychological mechanisms. A psychological mechanism is an information-processing procedure or decision rules that evolution by natural or sexual selection has equipped humans to possess in order to solve a particular adaptive problem. […] Psychological mechanisms mostly operate behind and beneath our conscious thinking [and] produce values and preferences which rational actors then pursue […] and they also engender emotions.”

Kanazawa stresses two important implications of EP: “human beings are just like other animal species” and “there is noting special about the brain as a human body part”, it was shaped by evolution. As the humans have not significantly evolved in the past 30,000 years, the human brain remains hardwired for those conditions found in the Savannah at the end of the Pleistocene (p.42). Hence the brain is not a tabula rasa but a tool adapted to this ancestral environment, in other words: biased (hence the Savannah Principle).

Overcoming this bias is possible through conscious effort but may be difficult. For instance, humans feel urges when confronted with high-calorie foods, but given contemporary conditions one ought to overcome the human bias towards sweets and fats. On the other hand some new situations may be difficult to comprehend and deal with. For example, the human brain may be tricked into engaging a friendship with a television character (mistaking the screen for real-life socializing, p.43).

Game theory

According to Game Theory (the so-called Prisoner’s Dilemma), when confronted with a choice between defection and cooperation, everything else remaining equal, defection is the rational choice (the well known Nash equilibrium). Moreover communication between the actors, if not supported by enforceable threats and promises will not affect the equilibrium. Yet in practice every other time the actors take an irrational decision and they also become significantly more likely to cooperate when they communicate.

For Kanazawa the reason for such an irrational outcome is that the complete anonymity between the subjects of the experiments is at odds with the reality of the savannah where one knew all the members of her 50-to-200-string band. One would interact with the same people all her life and thus there would be a strong evolutionary pressure to foster inherited cooperativeness (p.44). Anonymity and no future interaction were so foreign to the savannah way-of-life that cooperation has become somewhat the human brain’s default option.

Public choice

A public good is nonexcludable (any one can access it) and has jointness of supply (one’s consumption does not decrease the amount left for the others). As a result ownership is impossible and free ride is easy. Thus there is no incentive from a profit-maximizing point of view to contribute to the provision of public goods and thus they’ll never be produced. Nonetheless in practice common goods are routinely provided (this blog).

In theory large scale collective actions (strikes, protests, boycotts) should never take place due to the anonymity f individual choices and negligibility of each actor’s contribution (p.45). But in the savannah there were only small-scale collective actions (hunt, childcare) in which free ride was conspicuous. The brain is thus used to the individual contribution making a significant difference and to automatic enforcement and reacts in a crowd as if it only involved a few dozens of people.

Network Exchange Theory

If in an organisation, one has numerous exchange partners who themselves have few alternative, the one is likely to secure relatively more favourable outcome from the exchange (i.e. power). For instance in real-life corporations, those occupying these network nodes act as information brokers which allow them to accumulate social capital and they tend to be promoted faster (p.46). Indeed, very similar situations ought to have been found in the savannah early human populations (and indeed in numerous nonhuman primate societies), thus human brains are adapted to them. Hence there is no discrepancies between reality and theory.

Double auction markets

The competitive price theory has been very successfully applied in practice: several buyers and sellers successively close the difference between their asks and bids until a match is found (p.47). Demand, supply, value and cost are perfectly understood by primates and thus there is no reason for the human brain not to be adapted to an auction. Tellingly “oral double auctions […] were slightly more efficient than the computerized markets with same parameters”(p.48). In other words, humans are born traders.

Worth seeing

In a Prisonner’s Game, the players are more likely to cooperate if they can see each other even if they do not communicate which underline the importance of the face-to-face encounter as would have happened in the Savannah (on the other hand computerized messaging does not have such effect as the faceless screen is not recognized as a partner, p.49).


Kanazawa ends his article by addressing recommendations to business managers but they can also applied for scholars. Sex and age categories are genetically hardwired in the human brain and should be considered as such (and not merely as a cultural construct). It is not by chance that hyper-competitive young unmarried men are responsible for an overwhelming majority of innovations (p.51). The counterpart for this productivity is a tendency to take a lot of risk which may damage the whole group (p.52).

Kanazawa has a blog worth checking.

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