1. Universal Darwinism? We know that biological evolution requires replication with variation, plus natural selection for useful traits But Dawkins suggests that evolution will ALWAYS happen when these preconditions are met This evolution might not be biological!

2. Breeding ideas? It may seem silly to think of an idea, or a form of behaviour, breeding… –BUT breeding = creating a new copy –Whenever an idea is spread to another mind, a new copy of the information in that idea is created … so we can say that whenever someone hears a new idea or learns a new behaviour, that idea has successfully reproduced

3. How do ideas reproduce? Imitation –Animals very bad at this –Humans very good at this We readily imitate the behaviours of others –Linguistic behaviours –Fashions, hobbies, crazes

4. The evolution of culture So ideas reproduce (with variation) … –Are ideas selected? –Yes! What ideas will get selected? –i.e. What ideas will tend to spread? –Ideas which are good at spreading themselves!

5. Enter the meme Dawkins in The Selfish Gene: –“meme” as the unit of imitation –(just as “gene” is the unit of biological inheritance) –suggested that memes can evolve –groups of memes making up “idea animals” Theory elaborated by Blackmore (1999) and others (e.g. the philosopher Dennett) Key point: memes are selected for their usefulness to themselves, not to us! Memes as parasites?

6. What is co-evolution? As we have seen, species evolve by natural selection to fit their environment… … but part of that environment may be other organisms! Organisms can evolve to become dependent on one another (symbiosis)

7. Co-evolution in nature Intestinal bacteria Insects pollinating flowers The eukaryotic cell … and many other examples

8. Co-evolution can also occur in situations where one organism is parasitic on another bacteria specialize to invade other species, which in turn evolve defenses consider case of malaria, which may account for the persistence of the sickle-cell gene in some human populations

9. We might also consider co-evolution of different genes, at separate loci, within a single species For example, consider the stick insect, where genes that lead to the development of a body appearance that resembles a twig co-evolve with genes that lead to behavior that reinforces the camouflage

10. Language as co-evolution Deacon and Blackmore In this case we will consider co-evolution between genes and memes within a single species, rather than co- evolution between two species

11. What has this got to do with language? If we put these two ideas together… … we can see language as a bundle of behaviours, an “idea animal” –Its habitat is the human brain –It has evolved to fit that habitat Can we explain the origin and / or acquisition of language in these terms?

12. Blackmore (1999) Blackmore on the Big Brain: it evolved to allow us to store and spread memes better Blackmore on the origin of language: –What is language for? – she concludes it is for spreading memes Co-evolution: –language (made of memes) is evolving… –But our genes are evolving to fit our memes (inc. language) too

13. Deacon (1997) Deacon: key to language is symbol use –Control of social/sexual relationships Language evolves to fit its environment –Its environment is the brain of the child Language has therefore evolved to become easy for a child to learn –Deacon: this explains language acquisition Our brains have also evolved to accommodate language (co-evolution)

14. Summary Two theories based on language evolving to inhabit us, rather than us evolving to use language –Blackmore: meme theory –Deacon: language evolving to fit child’s brain Both theories involve co-evolution –Language and brain/body have evolved together, becoming co-dependent/symbiotic

15. Word of warning Both Deacon and Blackmore’s theories are relatively new… –… and fairly controversial They are only favoured by a minority of linguists e.g. the Chomskyans oppose this view