Also, the differences between chimp and human are pretty consistent with plain increase in the volume (and number of neurons), if you control for, hmm, cultural differences.
You seem to be making a mistake that a lot of people without experience programing computers make, namely that merely adding computational power without improving the algorithm is sufficient to generate (Edit: useful) new behaviors. This is especially not the case with the kind of ad hoc algorithms evolution tends to generate. You’re going to need new or at least improved algorithms, and if you’re evolving new algorithms, they’re going to be adapted to the environment you’re evolving in.
I don’t think knowledge of computer programming can be applied to brains through analogies involving “adding computational power” or “improving algorithms”. A computer’s processor, memory, algorithms and data are strictly conceptually separate and each can be modified without causing any change to the others. That’s not at all the case with a brain.
Who are you to say that I am making a mistake that a lot of people without experience programming computers make? Adjust your priors: I am successful software programmer, working in computer graphics, for quite a long time. That’s how i earn my living. In my life i wrote all sorts of software (of course not literally all, but still rather significant coverage). I’d say I am not making a mistake that a lot of people with little experience programming would make.
The whole point is that evolution is not generating most of the algorithms. Evolution generated a few, including a very powerful learning algorithm, which took very long time (note that power doesn’t equate to complexity; evolution itself is not very complex but is rather powerful). The very powerful learning algorithm allows to adapt to environment on-spot, as well as to the brain modifications. There are algorithms adding computer power to which allows to do ‘new tricks’. The new human behaviours, too, are not all that new—different in the extent, rather than in essence. We - not even all of us, some of us—search massively larger solution spaces than chimps do, but there isn’t a great deal of evidence that we do anything principally different (and especially not all humans).
edit: One other thing. We do have example of how novel modules evolve. Entire new areas of brain, like neocortex, appear—over a very large number of generations. What has happened in the small brained hominid to human evolution, though, is nothing like this. The number of generations is massively smaller, and the brain is pretty much up-scaled version of the original brain. Note that this happened against strong pressure for small brain size (childbirth difficulties)
and if i apply same prior to him as he applies to me, probably a person with little programming experience. Everyday tit-for-tat reflex (that one might have evolved because its conceivable it was good through much of our on-trees existence as well, albeit i’m a bit dubious as of how the DNA would code for something like tit for tat, in mammalian brain; it would code for something that sort of works like tit for tat, with a lot of side effects, such as getting irritated, and responding in the equivalent style; [learning what to be irritated at]).
So your claim is that the human brain is adaptable enough that it can rewire itself in reasonable ways in response to sense input, but so rigid that there are no easy mutations that would correspond to some of the behavioral changes evolutionary psychologists talk about.
The brain is adaptable, but the development process isn’t. You connect neurons by steering the growth cones through chemical gradients. Using the genes that affect large number of neurons at once.
Consider a centipede with, say, 40 segments. It is so flexible that it can lose a lot of legs and still walk, yet so rigid that you’ll have real trouble making a mutation which affects just the 27th segment (losing legs on it), requiring a lot of generations to specialize an ancient centipede into an insect (or spider, or crustacean). Why so? Because there aren’t 40 segments in the DNA, there’s 5..6 cell divisions when making cells that become the segments later. You need a whole lot of regulatory genes to just start addressing the segments individually from DNA. The DNA is not a blueprint.
That being said, I do agree that brain’s neuroplasticity can take advantage of some mutation that’s bridging two areas of the brain. How to use the data that comes over the bridge, however, is up to neuroplasticity to figure out.
You connect neurons by steering the growth cones through chemical gradients. Using the genes that affect large number of neurons at once.
Directly effecting neural growth patterns isn’t the only way for genes to effect human behavior. Consider for example, the effect on human behavior of drugs like caffeine, alcohol, anti-depressants, etc. Keep in mind any drug effect can be approximately stimulated by affecting any of the steps in the chemical cascade the drug uses.
Indeed. I’m not at all against the notion that the existing mechanisms can be adapted by evolution—whenever those are coded for. You can, most definitely, up or down regulate e.g. dopamine activity.
That is far cry from emergence of specialized modules, as per “organized into modules or mental organs, each with a specialized design that makes it an expert in one arena of interaction with the world. The modules’ basic logic is specified by our genetic program. Their operation was shaped by natural selection to solve the problems of the hunting and gathering life led by our ancestors in most of our evolutionary history” (Pinker 1997a, p. 21).
You seem to be making a mistake that a lot of people without experience programing computers make, namely that merely adding computational power without improving the algorithm is sufficient to generate (Edit: useful) new behaviors. This is especially not the case with the kind of ad hoc algorithms evolution tends to generate. You’re going to need new or at least improved algorithms, and if you’re evolving new algorithms, they’re going to be adapted to the environment you’re evolving in.
I don’t think knowledge of computer programming can be applied to brains through analogies involving “adding computational power” or “improving algorithms”. A computer’s processor, memory, algorithms and data are strictly conceptually separate and each can be modified without causing any change to the others. That’s not at all the case with a brain.
Who are you to say that I am making a mistake that a lot of people without experience programming computers make? Adjust your priors: I am successful software programmer, working in computer graphics, for quite a long time. That’s how i earn my living. In my life i wrote all sorts of software (of course not literally all, but still rather significant coverage). I’d say I am not making a mistake that a lot of people with little experience programming would make.
The whole point is that evolution is not generating most of the algorithms. Evolution generated a few, including a very powerful learning algorithm, which took very long time (note that power doesn’t equate to complexity; evolution itself is not very complex but is rather powerful). The very powerful learning algorithm allows to adapt to environment on-spot, as well as to the brain modifications. There are algorithms adding computer power to which allows to do ‘new tricks’. The new human behaviours, too, are not all that new—different in the extent, rather than in essence. We - not even all of us, some of us—search massively larger solution spaces than chimps do, but there isn’t a great deal of evidence that we do anything principally different (and especially not all humans).
edit: One other thing. We do have example of how novel modules evolve. Entire new areas of brain, like neocortex, appear—over a very large number of generations. What has happened in the small brained hominid to human evolution, though, is nothing like this. The number of generations is massively smaller, and the brain is pretty much up-scaled version of the original brain. Note that this happened against strong pressure for small brain size (childbirth difficulties)
He’s probably a person with programming experience...
and if i apply same prior to him as he applies to me, probably a person with little programming experience. Everyday tit-for-tat reflex (that one might have evolved because its conceivable it was good through much of our on-trees existence as well, albeit i’m a bit dubious as of how the DNA would code for something like tit for tat, in mammalian brain; it would code for something that sort of works like tit for tat, with a lot of side effects, such as getting irritated, and responding in the equivalent style; [learning what to be irritated at]).
So your claim is that the human brain is adaptable enough that it can rewire itself in reasonable ways in response to sense input, but so rigid that there are no easy mutations that would correspond to some of the behavioral changes evolutionary psychologists talk about.
The brain is adaptable, but the development process isn’t. You connect neurons by steering the growth cones through chemical gradients. Using the genes that affect large number of neurons at once.
Consider a centipede with, say, 40 segments. It is so flexible that it can lose a lot of legs and still walk, yet so rigid that you’ll have real trouble making a mutation which affects just the 27th segment (losing legs on it), requiring a lot of generations to specialize an ancient centipede into an insect (or spider, or crustacean). Why so? Because there aren’t 40 segments in the DNA, there’s 5..6 cell divisions when making cells that become the segments later. You need a whole lot of regulatory genes to just start addressing the segments individually from DNA. The DNA is not a blueprint.
That being said, I do agree that brain’s neuroplasticity can take advantage of some mutation that’s bridging two areas of the brain. How to use the data that comes over the bridge, however, is up to neuroplasticity to figure out.
Directly effecting neural growth patterns isn’t the only way for genes to effect human behavior. Consider for example, the effect on human behavior of drugs like caffeine, alcohol, anti-depressants, etc. Keep in mind any drug effect can be approximately stimulated by affecting any of the steps in the chemical cascade the drug uses.
Indeed. I’m not at all against the notion that the existing mechanisms can be adapted by evolution—whenever those are coded for. You can, most definitely, up or down regulate e.g. dopamine activity.
That is far cry from emergence of specialized modules, as per “organized into modules or mental organs, each with a specialized design that makes it an expert in one arena of interaction with the world. The modules’ basic logic is specified by our genetic program. Their operation was shaped by natural selection to solve the problems of the hunting and gathering life led by our ancestors in most of our evolutionary history” (Pinker 1997a, p. 21).