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andrewducker ([personal profile] andrewducker) wrote2012-03-06 11:00 am
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Interesting Links for 06-03-2012

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[identity profile] gwern branwen (from livejournal.com) 2012-03-07 08:12 pm (UTC)(link)
> 7) "Free efficiency gains in intelligence is never a bad thing" In evolutionary terms neither are they a good thing unless they are needed in the environment. You seem to have a weird idea that evolution increases "efficiency". This is simply untrue... evolution increases only the fitness to replicate genes. This is not the same as increasing fitness. Why on earth would evolution tinker around making us better at digesting things or more muscular unless a really significant proportion of people were starving or dying because they were insufficiently muscular?

Because muscles are *metabolically expensive*. Because digestion is *metabolically expensive*. See the footnotes on the chimpanzees, muscles, and guts!

(For god's sake, I'm not putting in all those references, links, and footnotes because they look pretty.)

[identity profile] steer.livejournal.com 2012-03-08 10:53 am (UTC)(link)
This whole "metabolically expensive" part highlights how you're thinking of the problem incorrectly. You are absolutely correct that they metabolically expensive are but if they were not, evolution would not go "wahey, free muscles, let's bulk up". If muscles were metabolically free and carried no penalty whatsoever humans would not aquire more unless there were an evolutionary reason to have them... unless they somehow increased our ability to propagate our genes. In the developed world almost nobody is in the situation where more muscle will do this. In the developing world possibly arguably this currently happens (remember we're not talking about situations where someone's life is better or easier because they're strong, we're talking about situations where a significant proportion live to propogate genes because they are).

I think this highlights your confusion between "fitness" in a weird role-playing game sense "Wow, that thing is smarter and stronger, it's obviously better" and "fitness" in the evolution sense "that thing sure can propogate its genes". This is why you automatically believe that a change in intelligence if it has no other costs will change evolutionary fitness.

[identity profile] gwern branwen (from livejournal.com) 2012-03-09 04:43 am (UTC)(link)
> If muscles were metabolically free and carried no penalty whatsoever humans would not aquire more unless there were an evolutionary reason to have them... unless they somehow increased our ability to propagate our genes. In the developed world almost nobody is in the situation where more muscle will do this.

Fitness gradients don't have to be big. Even in the developed worlds, pressure could come from various things: from slightly decreased homicide, from the ability to resort to manual labor to earn one's bread, to slight reduction in injury rates.

As people in finance say, a free option is never a bad thing. If using it would not be better than your existing options, well, you just let it expire unused. Muscles are a lot like an option: if you don't need them, you can just digest them and use the protein or calories for something else. See my previous point about additional efficiency in brain construction being useful even if no additional intelligence would be useful.

[identity profile] steer.livejournal.com 2012-03-09 09:11 am (UTC)(link)
Well I guess I will never convince you that evolution is not what you think it is.
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