Wednesday 1 October 2014

The most common misunderstanding of cultural evolution

A diagram has emerged in the coverage of the S.F.I. workshop that Daniel Dennett organized earlier this year. I think it neatly illustrates one of the most common misunderstandings about cultural evolution. First, here is the diagram:

The main problems here are not with the "cultural evolution" column. It appears that people understand cultural evolution! The problems are all in the "biological evolution" column. Every entry is wrong:

  • It is not true that - aside from culture - traits are only inherited from parents. Alice might have gotten her flea bites from her daughter, her warts from her grandmother and her chlamydia from her second cousin.
  • It is not true that transmission which is not down host generations happens in cultural realm and not in the organic realm. DNA-based traits can be inherited from offspring, as happened with Alice in the last example.
  • The speed of cultural evolution with respect to the organic realm is much exaggerated. If you look at areas where the generation time is comparable - such as medicine vs bacteria and viruses, the ideas simply aren't outstripping the pathogens in terms of the speed of their evolution. When people argue that cultural evolution is fast, they are mostly impressed by its short generation time and the large number of ideas. However, bacteria and viruses can reproduce quickly too. Plus they are far more numerous than ideas (and so they can perform many more experiments). Perhaps one day cultural evolution will unambiguously go faster.
  • Traits acquired during a human lifetime can be transmitted genetically. Fleas can be acquired during a human lifetime and are propagated genetically; AIDS can be acquired during a human lifetime and is propagated genetically - and so on.
  • People can choose which genetic traits they inherit. If you choose to never have sex, you won't inherit any syphilis genes, or any chlamydia genes. It's not true that you don't have a choice.
  • DNA is not the only medium of inheritance - aside from culture. Organisms inherit resource boluses from their parents. They inherit accommodation - as seen with rabbit warrens, beaver dams and dental carries. They inherit their location. The idea that DNA is the only medium of inheritance is wrong.
  • Lastly, even the column headings in this table are wrong. Culture is part of biology. Contrasting "cultural evolution" and "biological evolution" makes no sense.

If contrasting "cultural evolution" with "biological evolution" [sic] it is important not to use an out-dated characature of biological evolution that predates our understanding of the significance of symbiosis. If you mistkenly do that, you'll get the relationship between them all wrong.

I don't know who created this table. Anyway, they have helped to highlight a common misconception - so thanks are due.

Update 2014-10-15: I also saw this table on the "bioninja" web site. I suspect that is the original source.

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