It’d be a pointless point if there was a symmetry between fitness in the wild and fitness for our purpose. There isn’t—fitness in the wild is very seldom improved by loss-of-function mutations, whereas fitness for our purposes, starting from the species that have been evolving for fitness in the wild, very often is. Rapid success at breeding larger corn kernels is not going to generalize into rapid success at breeding ubermensch.
fitness in the wild is very seldom improved by loss-of-function mutations, whereas fitness for our purposes, starting from the species that have been evolving for fitness in the wild, very often is.
There’s no reason evolution would have already have optimized for all the intelligence-related alleles; if it had, they would have reached fixation.
Rapid success at breeding larger corn kernels is not going to generalize into rapid success at breeding ubermensch.
I think it is. All the genetic data seems to point to: much of intelligence is genetic, highly polygenic, not fixated, and additive. All of that translates to breedability: we have a lot of easily identified variants present in only parts of the population; hence, breedable.
There’s no question that evolution can continue. The issue is that the rate you can attain for different traits differ. For example, evolving smaller animals from larger animals (by a given factor) is an order of magnitude faster process than evolving larger animals from smaller animals. ( http://news.ucsc.edu/2012/01/body-size.html ). I think you wouldn’t disagree that it would be far quicker to breed a 50 point IQ drop than 50 point IQ rise?
we have a lot of easily identified variants present in only parts of the population
I guess you refer to those studies on intelligence genes which flood the popular media, which tend to have small effect sizes and are of exactly the kind that is very prone to superfluous results.
For example, evolving smaller animals from larger animals (by a given factor) is an order of magnitude faster process than evolving larger animals from smaller animals. ( http://news.ucsc.edu/2012/01/body-size.html ). I think you wouldn’t disagree that it would be far quicker to breed a 50 point IQ drop than 50 point IQ rise?
But what does that have to do with breeding for our objective purpose? It may be easier to destroy functionality than create it, but evolution is creating functionality for living in the wild and doing something like hunting mice while we’re interesting in creating functionality to do something like understand human social cues and trading off against things like aggression and hostility towards the unknown. In both cases, functionality is being created and trading off against something else, and there’s no reason to expect the change for one case to be beneficial for the other. Border collies may be geniuses at memorizing words and herding sheep and both of these feats required intense selection, but both skills are worse than useless for surviving in the wild as a wolf...
I guess you refer to those studies on intelligence genes which flood the popular media, which tend to have small effect sizes and are of exactly the kind that is very prone to superfluous results.
The original studies, yes, the ones like candidate-gene studies where n rarely is more than a few hundred, but the ones using proper sample sizes like n>50000 and genome-wide significance level seem trustworthy to me. They seem to be replicating.
Well, my point was that you can’t expect the same rate of advances from some IQ breeding programme that we get when breeding traits arising via loss-of-function mutations.
Sure, there’s a huge genetic component, but almost none of it is “easily identified”.
Generally you can expect that parameters such as e.g. initial receptor density at a specific kind of synapse would be influenced by multiple genes and have an optimum, where either higher or lower value is sub-optimal. So you can easily get one of the shapes from the bottom row in
i.e. little or no correlation between IQ and that parameter (and little or no correlation between IQ and any one of the many genes influencing said parameter).
edit: that is to say, for example if we have an allele which slightly increases number of receptors on a synapse between some neuron type A and some neuron type B, that can either increase or decrease the intelligence depending on whenever the activation of Bs by As would be too low or too high otherwise (as determined by all the other genes). So this allele affects intelligence, sure, but not in a simple easy to detect way.
There isn’t—fitness in the wild is very seldom improved by loss-of-function mutations
I am not sure this is generally true.
The wild equivalent to “fitness for our purposes” is a drastic change in the environment which starts to select for different criteria. In such conditions organisms certainly select for new-useful-function mutations, but they also select for loss-of-no-longer-useful-function mutations. Functionality tends to be expensive (e.g. in energy) and if you don’t need it, you’re better off discarding it.
Those drastic changes rarely happen, though. In humans, the most recent very well known one was adult lactose tolerance—something that switched lactase off in adulthood no longer does.
edit: and somewhat back to the original point with regards to eugenics—humans have been evolving intelligence for a while already, so selection for intelligence doesn’t seem like a dramatic change.
That, by the way, is an interesting example of both adding functionality (now adults can drink milk!) and losing functionality (the gene which turns off lactase production in adulthood got broken and no longer works in many people).
Yeah. Anyhow, my original point has to do with attempts to breed humans for intelligence. Humans have been evolving for greater intelligence for a very long time now, any free easy gains already been made. You could probably get larger brain volume rather easily with birth by caesarian only, but that doesn’t seem like a good idea to me.
Humans have been evolving for greater intelligence for a very long time now, any free easy gains already been made.
I don’t know. It may or may not be true, but it doesn’t look obvious to me.
The issue is that “evolving for greater intelligence” competes with other things like “evolving for greater strength” or “evolving for greater alpha-ness” or maybe even simply “evolving to survive famines”.
Because of TANSTAAFL greater intelligence comes at a cost (as a trivial example, the human brain consumes a LOT of energy) and the trade-offs the evolution makes are appropriate for the then-current environment. And our current environment is markedly different (there’s your drastic change) from the one in which modern humans actually evolved.
It is quite possible that some trade-offs which held down the growth of intelligence are no longer operational and humans can/will continue to evolve towards even higher IQ.
Practically, of course, the point is moot as evolution is very very slow and humans will self-modify much more rapidly than evolution could provide any noticeable gains.
It is quite possible that some trade-offs which held down the growth of intelligence are no longer operational and humans can/will continue to evolve towards even higher IQ.
Maybe, but as you say, it would come at potential cost. E.g. gain of a few points but you won’t survive famine, that doesn’t sound very good.
Or much more insidiously, gains on an IQ test, at the expense of ability to form/organize/use complex background knowledge (IQ tests are designed to be minimally affected by extra background knowledge).
Practically, of course, the point is moot as evolution is very very slow and humans will self-modify much more rapidly than evolution could provide any noticeable gains.
Yeah, either that, or the civilization goes kaput and it’s back to all-natural selection.
It’d be a pointless point if there was a symmetry between fitness in the wild and fitness for our purpose. There isn’t—fitness in the wild is very seldom improved by loss-of-function mutations, whereas fitness for our purposes, starting from the species that have been evolving for fitness in the wild, very often is. Rapid success at breeding larger corn kernels is not going to generalize into rapid success at breeding ubermensch.
There’s no reason evolution would have already have optimized for all the intelligence-related alleles; if it had, they would have reached fixation.
I think it is. All the genetic data seems to point to: much of intelligence is genetic, highly polygenic, not fixated, and additive. All of that translates to breedability: we have a lot of easily identified variants present in only parts of the population; hence, breedable.
There’s no question that evolution can continue. The issue is that the rate you can attain for different traits differ. For example, evolving smaller animals from larger animals (by a given factor) is an order of magnitude faster process than evolving larger animals from smaller animals. ( http://news.ucsc.edu/2012/01/body-size.html ). I think you wouldn’t disagree that it would be far quicker to breed a 50 point IQ drop than 50 point IQ rise?
I guess you refer to those studies on intelligence genes which flood the popular media, which tend to have small effect sizes and are of exactly the kind that is very prone to superfluous results.
But what does that have to do with breeding for our objective purpose? It may be easier to destroy functionality than create it, but evolution is creating functionality for living in the wild and doing something like hunting mice while we’re interesting in creating functionality to do something like understand human social cues and trading off against things like aggression and hostility towards the unknown. In both cases, functionality is being created and trading off against something else, and there’s no reason to expect the change for one case to be beneficial for the other. Border collies may be geniuses at memorizing words and herding sheep and both of these feats required intense selection, but both skills are worse than useless for surviving in the wild as a wolf...
The original studies, yes, the ones like candidate-gene studies where n rarely is more than a few hundred, but the ones using proper sample sizes like n>50000 and genome-wide significance level seem trustworthy to me. They seem to be replicating.
Well, my point was that you can’t expect the same rate of advances from some IQ breeding programme that we get when breeding traits arising via loss-of-function mutations.
They don’t seem to be replicating very well...
http://arstechnica.com/science/2014/09/researchers-search-for-genes-behind-intelligence-find-almost-nothing/
Sure, there’s a huge genetic component, but almost none of it is “easily identified”.
Generally you can expect that parameters such as e.g. initial receptor density at a specific kind of synapse would be influenced by multiple genes and have an optimum, where either higher or lower value is sub-optimal. So you can easily get one of the shapes from the bottom row in
http://en.wikipedia.org/wiki/Correlation_and_dependence#/media/File:Correlation_examples2.svg
i.e. little or no correlation between IQ and that parameter (and little or no correlation between IQ and any one of the many genes influencing said parameter).
edit: that is to say, for example if we have an allele which slightly increases number of receptors on a synapse between some neuron type A and some neuron type B, that can either increase or decrease the intelligence depending on whenever the activation of Bs by As would be too low or too high otherwise (as determined by all the other genes). So this allele affects intelligence, sure, but not in a simple easy to detect way.
I am not sure this is generally true.
The wild equivalent to “fitness for our purposes” is a drastic change in the environment which starts to select for different criteria. In such conditions organisms certainly select for new-useful-function mutations, but they also select for loss-of-no-longer-useful-function mutations. Functionality tends to be expensive (e.g. in energy) and if you don’t need it, you’re better off discarding it.
Remnants of lost functionality are common.
Those drastic changes rarely happen, though. In humans, the most recent very well known one was adult lactose tolerance—something that switched lactase off in adulthood no longer does.
edit: and somewhat back to the original point with regards to eugenics—humans have been evolving intelligence for a while already, so selection for intelligence doesn’t seem like a dramatic change.
That, by the way, is an interesting example of both adding functionality (now adults can drink milk!) and losing functionality (the gene which turns off lactase production in adulthood got broken and no longer works in many people).
Yeah. Anyhow, my original point has to do with attempts to breed humans for intelligence. Humans have been evolving for greater intelligence for a very long time now, any free easy gains already been made. You could probably get larger brain volume rather easily with birth by caesarian only, but that doesn’t seem like a good idea to me.
I don’t know. It may or may not be true, but it doesn’t look obvious to me.
The issue is that “evolving for greater intelligence” competes with other things like “evolving for greater strength” or “evolving for greater alpha-ness” or maybe even simply “evolving to survive famines”.
Because of TANSTAAFL greater intelligence comes at a cost (as a trivial example, the human brain consumes a LOT of energy) and the trade-offs the evolution makes are appropriate for the then-current environment. And our current environment is markedly different (there’s your drastic change) from the one in which modern humans actually evolved.
It is quite possible that some trade-offs which held down the growth of intelligence are no longer operational and humans can/will continue to evolve towards even higher IQ.
Practically, of course, the point is moot as evolution is very very slow and humans will self-modify much more rapidly than evolution could provide any noticeable gains.
Maybe, but as you say, it would come at potential cost. E.g. gain of a few points but you won’t survive famine, that doesn’t sound very good.
Or much more insidiously, gains on an IQ test, at the expense of ability to form/organize/use complex background knowledge (IQ tests are designed to be minimally affected by extra background knowledge).
Yeah, either that, or the civilization goes kaput and it’s back to all-natural selection.
Think of this in terms of complexity (use your favorite measure). The point is that evolution has a much easier time reducing it than increasing it.