Lecture: the biological basis of human culture

1. How does Darwinian evolution work? Opposite of Lamarkian evolution; it requires an advantageous mutation. This implies a timescale for adaptation to new environment (ecological niche): on the order of a million years.

2. What is the structure of the overall relation of living organisms? The phylogenetic tree. Opposite of the unilineal evolution proposed by sociobiologists such as Arthur Jensen. ex: octopus is a mollusc, like the clam or snail, but has encephalization higher than some vertebrates (like lizards). Jensen's model goes back to Plato, who first discussed biological determinism as a useful myth for elitists.

3. Some niches require high degree of encephalization (brain to body ratio) -- how is this created? Manipulatory feedback (interactive manipulation with the environment). Humans have two types: hand and language. Together these are capable of creating culture: learned and shared behavior.

4. Culture is based on Lamarkian evolution (learned information can be passed on to next generation), unlike biology's Darwinian evolution. This implies a very different timescale for adaptation to new environments: on the order of a thousand years.

5. Modern humans originated in Africa around 100,000 years ago. How did they spread over so many different environments in such a short amount of time? The shorter time scale of Lamarkian adaptation. For this reason, we are -- unlike any other species -- 99.99% genetically identical.

6. If we are so genetically identical, then why do people in different countries act so differently? These are cultural differences, not genetic differences. ex. higher student math scores in Japan than U.S. is due to U.S. mythology of biological determinism ("don't worry, you just inherited my bad math skills) versus work ethic in Asia ("don't worry, you just need to study more").

7. What is the structure of the overall relation of cultures? Just as unilineal ranking was incorrect for biological evolution, it is also incorrect for cultural evolution. There is an astounding diversity of cultural adaptations. ex: Political organization varies from band societies (no leader) to tribal societies (low-hierarchy leader) to state societies (high-hierarchy). But we tend to see nuclear families in both state and band societies. ex: Most people in the U.S. use bilateral descent (related to both mother and father). But majority of societies in the world are unilateral. Matrilineal societies (related to mother's line only) passes wealth from father to mother's son, in direct contradiction to predictions of sociobiologists and other biological determinists.