In an article for the Journal of Theoretical Biology, Herbert Gintis provides a model that shows that:

“if an internal norm is fitness
enhancing, then for plausible patterns of socialization, the allele for
the internalization of norms is evolutionarily stable.”

Further he posits that this view can be used to model Herbert Simon’s 1990 explanation of altruism.  Simon’s idea is that altruistic norms “Hitchhike” on the backs of the general tendencies of internal norms to be “personally fitness enhancing”.

OK, cool, so what is an “internal norm”?  It’s a pattern of behavior that is regulated by internal controls or “sanctions”.  We’d think of these like shame or guilt, the little guy sitting on your shoulder with the white outfit arguing against the little guy on the other shoulder in the red outfit.

Gintis makes the point that our very capacity to internalize norms like guilt and shame means that humans have what he calls “socially programmable” objective functions.  An objective function is an economics idea.  The point is that humans have these functions that they try to optimize (or maximize) subject to particular constraints.

So, human behavior is dependent not only on the beliefs they hold about their objective functions (if I choose to take action A, then the outcome is result R), but also on their “values”.  The values are the goals, or the reasons for why they would take a particular action in the first place.

He goes on:

“Suppose there is one genetic locus that controls the capacity to internalize norms.  I develop models of gene-cultural coevolution to show that if an internal norm is fitness enhancing, then the allele for internalization of norms is evolutionarily stable.  Moreover, if the fitness payoff to the internalized norm is sufficiently large, or if there is a sufficiently high rate of phenotypic level assortative mating, the allele for internalization is globally stable.”

It’s important to discuss what he means by “evolutionarily stable”.   The idea was developed by John Maynard Smith.  In his book, “Evolution and the Theory of Games", he describes it as such:

“A ’strategy’ is a behavioral phenotype; i.e., it is a specification of what an individual will do in any situation in which it may find itself.  An ESS (Evolutionarily Stable Strategy) is a strategy such that, if all the members of a population adopt it, then no mutant strategy could invade the population under the influence of natural selection.”

Gintis has been spearheading a move for the past 20 or 30 years to make evolutionary game theory (and the use of the ESS) the standard in Social Science research modeling, as opposed to classical game theory.  But, that’s another topic.

He is attempting to make a case, in this article, that people value behavior that can be described as altruistic (bravery, fairness, empathy, etc) for its own sake.  This is in contrast to the notion that people are altruistic because in the long term it is in their best interest.  This means that:

“A person who has internalized the value of ’speaking truthfully’ will do so even in cases where the net payoff to speaking truthfully would otherwise be negative.”

Further, he argues that a norm will be more prevalent in a population if it is internalized by a the individuals in that population than if it is only followed when those individuals think it is in their best interest.

He uses his model to elucidate the way in which altruistic internal norms can drive out norms that are harmful both socially and to the individual.  He finds that altruistic cooperation and punishment (in his model) don’t depend on “repeated interaction, reputation effects, or multi-level selection”.  Even though an individual who carries the gene for altruistic behavior and the altruistic norm can suffer a personal cost (as per the definition of altruism), it doesn’t negatively affect the group.  That is, there is no in-group net negative effect.  It is in fact because of this pro-social effect that the strategy of the altruistic norm can be an ESS.

Basically, Gintis provides a model that shows that it is possible to fix an altruistic gene in a population for particular types of behavior that are good for the group as a whole, even through they hurt the  individual.


  • Gintis, Herbert.  2003.  “The Hitchhiker’s Guide to Altruism: Gene-culture Coevolution, and the Internalization of Norms.”  Journal of Theoretical Biology. 220, 407-418.

  • Smith, John Maynard.  1982.  Evolution and the Theory of Games. Cambridge University Press.