The one sentence summary

Cultural transmission is now mainly broad, shallow and fast, and has little connection with traditional knowledge.


  • Cultural change is accelerating, as long-evolved traditions and knowledge are being replaced by vast and instantaneous internet phenomena.
  • Evolution is about three things:
  1. Variation: any departure from what has previously been done.
  2. Transmission: how this is conveyed to someone else.
  3. Sorting: categorising knowledge and how we do things.
  • Cultural transmission (the spreading of ideas, concepts, and beliefs) is every bit as powerful as genetic transmission. It has changed dramatically in recent times from thin and deep (traditional learning and knowledge) to broad and shallow (a widely-shared horizon).
  • The tempo of knowledge creation (horizons) has accelerated to the point where it has little connection with ancestral knowledge (traditions).
  • Most of society adopts a copying strategy. Only 5% of people are originators (producers). That’s enough to set direction, like one or two fish leading a school – the remaining 95% are social-learning scroungers.
  • Cultural recipes passed down through lines of descent only survive if they are capable of being replicated and transmitted, with some evolution known as guided variation. Cultural attractors are elements that get preferentially retained over generations – Little Red Riding Hood is over 2,000 years old, and has barely changed.


  • Phylogenetic trees are diagrams that show the evolution and branching off of physical and genetic characteristics. A clade is a group believed to constitute all the evolutionary descendants of a common ancestor.
  • There’s a difference between emulation (copying just the outcome or goal), and imitation, which means copying the method to get to the goal.
  • Extended phenotypes are inherited traits outside the body, such as hand axes and iphones.
  • An obsession with novelty is WEIRD: Western, educated, industrialised, rich, and in democratic societies. Eastern cultures are much happier with conformity.
  • In the wisdom of individuals, we make Bayesian guesses about tomorrow based on what happened today, constantly refining our worldview, and we are usually about right (named after statistician Thomas Bayes).
  • Homophily is the clustering of likeminded people.
  • Eight-person teams work best, and better than individuals, four-person teams, or even those with 16.
  • More complex societies and their religions tend to have more punishing moralistic gods, and their people are more generous (which came first?).
  • Slacktivism is the facile online support of a trendy cause, where typically over 99% make no monetary donation.
  • Algorithms build on algorithms in a process called supervised learning, where thousands of successive estimates are checked against the correct answer, making them more and more accurate.


  • This may be too academic for some, but it is well written in plain language and relatively short, so should suit most inquiring minds.