Monday, 15 October 2018

For memes, minds are like islands

Islands are natural evolutionary experiments. The history of evolutionary theory prominently features researchers who visited islands. Most famous of these was Darwin himself. Darwin's trip to the remote Galapagos islands was famously documented in The Voyage of the Beagle. This took place before Darwin had really got interested in evolutionary theory - and it was clearly a catalytic event.

Islands feature restricted gene flow. They also feature rapid evolution due to the environment being different from the ancestral one, and due to small population sizes and genetc drift. The size of the island and how isolated it is are important factors to the resulting evolutionary dynamics.

It has subsequently become understood that islands are a special case of restricted flow of heritable information. That means that the great lakes are like watery islands for fish. It means that deserts are like islands for cacti. It means that that mountains are like islands for their plants and animals. It also means that many hosts are like islands for their parasites.

Dogs are like islands for their fleas. Zits are like islands to their bacteria - and minds are like islands for their memes. Evolutionists got the most mileage out of archipelagos far from the mainland. The memetic equivalent would be lost or isolated tribes. Sure enough, anthropologists have long been fascinated by these types of group. Remote monasteries another possible object of study - and of course groups of humans can themselves become isolated on real islands.

Islands are natural experiments in group selection. Theory has long suggested that if the number of migrants per generation between groups falls to around 1, then groups of sexual organisms can start to behave rather like individuals which develop their own, distinct traits. They start to develop persistent differences between one another - instead of simply being part of the same gene pool. One migrant per generation is not very many and so conventional wisdom has argued that group selection is not very important. However, one place where isolation levels can be high is on islands. If an island is sufficiently remote, it is not very challenging to get into the ballpark of 1 migrant per generation.

Reproduction within islands is subject to one set of selection pressures, while reproduction between islands is often subject to a quite different set of selection pressures. Strawberry plants illustrate how such selection can pull organisms in two different directions. Strawberries have runners for local, asexual reproduction and seeds for sexual reproduction over large distances. Strawberries must allocate resources depending on their local conditions. If they are cramped, and under seige from parasites, then seeds start looking like an attractive option. This type of resource allocation dilemma is a common one for organisms on islands. Memes too must allocate their resources between fighting off competition within their existing mind and spreading to new minds. As with strawberry plants, they are often pulled by selection in two conflicting directions.

Islands are widely considered to be incubators of evolutionary innovation. On the mainland experiments often don't get very far before reality catches up with them and calls them to account. On islands, experients can last for longer before their day of reckoning comes. Often, rats come to the island, and destroy its native ecosystem - and that is the end of that. However, once is a while something amazing happens, and the island evolution produces something valuable that would never have evolved without the isolation. In the USA, many small start-ups attempt to reproduce this innovation-on-islands effect. Most fail, but sometimes, something amazing happens.

The evolutionary dynamics of island ecosystems seems like fertile ground for cultural evolution and memetics. It is territory that has already been explored to some extent, but there is still much left to learn.

There's an interesting analogy between organisms colonising a new volcanic island and individual enculturation of human brains. In both cases, pioneer species come first and create the ecosystem for their successors.

One of my early essays was about evolution on islands. I wasn't thinking about cultural evolution much back then. It is interesting for me to look back on the essay, now I that know more about the relevance of island dynamics to memetic evolution.

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