Monday, March 21, 2016

Copying complex adaptations

This is the followup post that I promised to write when I did my review of The Secret of Our Success.  Sorry it took so long.

Well, something that occurred to me when I was reading that book was that the rate at which mutations crop up governs how fast you can change.  There's no way to develop a tolerance for lactose unless that mutation happens to occur in someone.  But the rate of mutation must also govern how complex an organism or simple society can get.  There's only so much selective pressure out there and each new mutation that isn't doing you any good requires, on average, on excess death to remove it from the gene pool.  And since each gene is an opportunity for something to go wrong in reproduction a higher rate of mutations must mean a smaller genome if your typical organism has the same number of offspring.

The same with cultural knowledge.  If you're living in a band without economic specialization and people discover things by trial and error then the sophistication of the skills people develop is going to be governed by how accurately they can copy each other.  And as The Secret of Our Success did a good job of demonstrating humans are really good at copying each other compared to monkeys, unlike common monkey stereotypes.  The knowledge around manioc consumption I discuss in the review isn't anything a single individual will be able to discover in their lifetime but it's something that groups of humans can learn over time.  Essentially nobody in a culture has any idea why they're soaking the manioc so long but they do it that way because that's how it's been handed down to them.

In the modern world we've managed to assemble a large amount of cultural information but we've got two advantages.  The first is specialization.  Well, really pretty much every culture has had some level of specialization in terms of gender roles and many had more than that but the modern world has a bewildering array of butchers, bakers, candle stick makers, etc.  The second is that we're lucky enough that a lot of the reasons we do things are known to us.  You can show a chess  board to an expert in the game and they'll probably be able to remember the positions of the pieces accurately but if you do the same with someone who doesn't know the rules of chess then they won't.  That's because the piece positions stem from an underlying order that is simpler than what's on the board and which the expert can recognize.  Western civilization is probably lucky that the steps required to turn wheat into flour have obvious purposes in a way the preparation of manioc doesn't.

Sometimes this can go wrong.  Here is an excellent blog post on how western civilization forgot how to prevent scurvy for various reasons but mostly because they thought then understood the why of the cure but they really didn't.  I had no idea before I read that that preparing limes in copper vessels might make the juice ineffective as a scurvy cure but apparently it does.  And so we come back to the need to copy inventions closely and only make changes when we can test to see if they work.

The modern world we live in is an awesome but also very fragile thing.  Even the creation of a pencil requires more knowledge than any single person has.  We're all embedded in this economic system that allows specialization but despite what you might think that system isn't natural but is also the product of long evolution.  If you ever read Debt: The First 5000 Years you'll see that even arbitrary barter isn't something that people just come up with.  Most societies don't really have trade and most which do only trade particular items for other particular items.  It requires a lot of social and legal evolution before you can have something like money which you can trade for meat, bread, candlestick, or pencils.  The author of Debt thinks that we ought to go back to past systems but I'm not willing to give up my pencils.

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