Green Beards, Altruism and Kinship – Halfway through Behave by Robert Sapolsky

Kin selection is the theory that we behave more altruistic towards people who share our genes—-given we believe in the darwinian paradigm that the overarching aim for an organism is to further its genes, of course.

Or as John Haldane humorously concluded while working on the mathematics of kin selection:

“I would lay down my life for two brothers or eight cousins.”

The idea being that brothers and sisters share genes by 50% and cousins 12,5%. The math being something like this:

1 person = 8 cousins (12.5×8=100)

1 person = 4 nephews (4×25=100)

1 person = 2 siblings (2×50=100)

The Green Beard Effect started as a thought experiment that would explain why we exhibit altruistic behaviors towards people who share a genetic trait with us, i.e a green bearded person favors another green bearded person over someone else. It’s is a poor mans version of kin selection.

The behavior has been confirmed studies on fire ants in 1998.

… and a Review of Behave by Robert Sapolsky is coming soon!


Thoughts on: “The Third Chimpanzee” by Jared Diamond

There is a 1.2 percent difference in DNA between humans and chimpanzees. But what is it that makes humans able to fly into space and create weapons so powerful that they can annihilate the earth as a whole? When did we separate into our own species and what triggered our evolutionary leap forward to become the rulers of he world?


This is another book I picked out from Charlie Mungers list of book recommendations. And that list is a gift that keeps giving. This book is amazing. It covers a wide range from fields like anthropology, history and linguistics to evolutionary biology but it still feels like a coherent.


The book is split up into 5 parts. The relationship between man and chimp, “sexual selection”, “world conquest” and “environmental impacts and extinction”. Here are some outtakes from my notes:


“An alien zoologist from outer space. would easily guess that humans are a mildly polygamists species. It turns out that harem size corresponds to female vs male body size ratio. ”


“From a study made on people growing up in a kibbutz; we learn not to have sex with people we are intimately associated with up to a age of six. ”


“There is no correlation between linguistic and social complexity. Primitive societies have as complex languages as advanced ones.”


There is a lot fascinating things to learn from this book, like, why human men have medium sized balls compared to chimps and gorillas. 😀 But is gets a darker tone towards its conclusion when we have to face the facts that we have some really huge obstacle ahead of us if we want the human species to continue to thrive in the future given the limited resources of the earth. J.D sees that the continuos homogenization of societies as the chief hope in our survival as a species. Creating the conditions to globally solve environmental issues together.

Loss of cultural diversity might be the price we have to pay for survival.



Check out my reading lists for more great books!