Cooperation in evolutionary context
‘Cui bono’ for selfishness
2020-04-26 — 2025-07-16
Wherein the evolution of cooperation is surveyed in a didactic mood, and the role of altruistic punishment as a costly mechanism for enforcing group norms is described and situated among kin and group selection.
In the pyramid of life’s organizational complexity, cooperation happens when parts at one level help each other out for the apparent benefit of another level. Whenever that happens, we argue about who benefits. How do we develop the moral wetware to support interpersonal institutions with non-myopic benefits?
The evolution of cooperation in organisms across varying degrees of complexity. Group selection, kin selection, eusociality, miscellaneous other mechanisms, and multi-level selection. Does it happen, and if so, how much?
1 What is selected?
W. M. Muir and Craig (1998) puts the “coop” in “cooperation”. Brian McGill’s parable of the hens is a plain explanation:
High productivity egg-laying is associated with aggression — indeed the highest egg layers are basically the ones that beat up the other hens in the coop with them and capture the most resources. […]
Then in the 1980s people got the idea to use group selection. Instead of picking individuals that were most productive, they selected entire hen houses that were most productive to produce the next generation
So that’s an existence proof of group selection, albeit under some contrived circumstances. See also (Hester et al. 1996; William M. Muir, Cheng, and Croney 2014).
For a complementary, glass-half-empty perspective, see Kevin Simler, The Leaning Tower of Morality:
The only way to get group selection to work out, mathematically, is under very specific conditions. (1) Groups have to be fairly isolated from each other, enough that sociopaths can’t jump freely from group to group. And (2) they need enough time in isolation to allow group-level advantages to produce demographic gains. However, (3) the groups also need to come together periodically to remix their members. This all hinges on Simpson’s paradox, and you can read more about it here: Fletcher and Zwick (2007) and Powers, Heys, and Watson (2012).
2 Parochial altruism
Choi and Bowles (2007):
Altruism—benefiting fellow group members at a cost to oneself—and parochialism—hostility toward individuals not of one’s own ethnic, racial, or other group—are common human behaviours. The intersection of the two—which we term “parochial altruism”—is puzzling from an evolutionary perspective because altruistic or parochial behaviour reduces one’s payoffs by comparison to what one would gain by eschewing these behaviours. But parochial altruism could have evolved if parochialism promoted intergroup hostilities and the combination of altruism and parochialism contributed to success in these conflicts. Our game-theoretic analysis and agent-based simulations show that under conditions likely to have been experienced by late Pleistocene and early Holocene humans, neither parochialism nor altruism would have been viable singly, but by promoting group conflict, they could have evolved jointly.
3 Altruistic punishment
Famously, humans are altruistic in the technical sense: they make systematic choices that impose great costs on themselves to benefit others. But those choices aren’t always nice! People tend, that is to say, to be altruistic punishers. We have a high appetite for enforcing rules and wreaking vengeance on those who break them, even if it does us personally no good (Bernhard, Fischbacher, and Fehr 2006; Bowles and Gintis 2004; Boyd and Richerson 1992; Hetzer and Sornette 2013a, 2013b, 2009). Much has been made of this; the evolutionary explanations are rather interesting.
4 How noisy can evolutionary selfishness mechanisms be and still be useful?
Decision theory in evolution
TBD: how much does evolution need to know about whom it is helping?
5 Mistake theory of cooperation
How much can evolution know about whom it is helping? This is a noisy regression problem. How likely is this action to actually propagate my genes/memes/whatever?
6 Incoming
Derek Thompson, The Most Efficient Way to Save a Life
As Sam Kean explained in The Atlantic article “The Man Who Couldn’t Stop Giving,” the mainstream theory of altruism’s roots is known as “kin selection”. Since the engine of evolution is procreation, any gene pool should be rewarded for the instinct to help relatives (including distant relatives) survive and pass along their genes—even when that assistance requires great sacrifice. Altruism, in this interpretation, is natural rather than super-human.
The Constant: A History of Getting Things Wrong episode The Greater Good covers W. D. Hamilton and George R. Price (Price 1972)
Other fun versions of this story:
- Dylan Matthews, biologist George Price’s life and death
- Michael Regnier, How Discovering an Equation for Altruism Cost George Price Everything
What collective moralities are possible? I think about them as moral orbits and writing about them is on my to-do list.