Re: Evolution, "adaptation", and what's currently adaptive
Len Piotrowski (email@example.com)
Wed, 4 Sep 1996 18:52:42 GMT
In article <firstname.lastname@example.org> email@example.com (Bryant) writes:
>Actually, I presented no smoke screen. I did do two things, out in the
>open. One, I pointed out that for sugar appetite/craving to be the
>result of accidents rather than selection, so too must be the hardware
>with which we detect sugar (the sugar-sensitive taste buds).
Appeared from here that you were "explaining" sugar craving as a functional
adaptation. And that brain development was a direct result of (had a need
for) the effects of sugar, a limiting environmental resource.
>Secondly, I concluded that you're correct, that I shouldn't be advocating
>a specific adaptationist hypothesis wrt these traits, since I originally
>used them only as crude examples to illustrate how current adaptiveness
>isn't always expected for adaptations.
I guess I've gotten this message, but not quite in this manner. If "sugar
craving" and "jealousy" are not currently adaptive for humans, why should they
have ever been adaptive for humans?
>I'm not squirming. I conceded to your point. I then clarified what I
>thought were the worthy points remaining to be made before moving on.
>You really do get worked up at the keyboard, don't you? :)
I get "worked up," in your opinion, by your incongruity.
>Sure, or since you seem to reject the presence of taste buds***, pick
>another trait. Say, nipples. Or peni. Or vermaronasal organs.
I never rejected the "presence" of taste buds, nipples, peni, vermaronasal
organs, or any other physical trait, nor doubted the probable evolutionary
development of these characteristics. Concurrent to pointing out the
incongruity of your critique of Gould & Lewontin while at the same time
presenting functional examples, I challenged your application of the
adaptationist functional paradigm to aspects of meaningful human behavior.
>Yes, contributions to the survival of the organism will result in a
>selective favoring of genes (as long as they lead to reproductive success
>of some sort). But that's not the point I was making. Please do not be
>embarassed to ask what "pleiotropy" means, etc., when you don't know.
>No big deal. (This isn't a lame attempt at an insult. It's an offer to
I'm not embarassed. Thanks for the magnanimous offer! Perhaps I was a bit too
subtle. The implication was that functionalism depends on "organism" not
"trait," pleiotropically "tied" or not, in order to vitalize a notion of
>>>>Eyes are adaptations because they have design features unlikely to have
>>>>accumulated by chance.
>>>>They serve fitness-enhancing functions.
>>>You don't know why "they" first appeared, or why "they" happened to be
>>>retained, or if and when "they" served as " fitness-enhancing functions"
>>>or for whom or what. This kind of story is about useless to illustrate any
>>>principle you may be striving for in describing meaningful human behavior as
>>>the result of functional adaptation.
>If you would stop using such vague and general descriptions, and come
>down to describe an actual example--say, maternal reactions to baby
>cries--it may help me understand your position.
The maternal reaction to baby cries, as well as the baby's cries reacting to
maternal behavior, I understand as a meaningful human interaction not "traits"
selected for by nature.
>>>>The only alternative to random accumulation in evolution is selection.
>>>"Random accumulation" of what? This is getting more and more remarkable.
>Lenny, do you really not undestand the first thing about evolutionary
I really don't understand how your "babies cries" are an accumulation of
>You've been letting on that you do, but these details you find
>so remarkable are basic intro biology.
So "babies cries," "sugar craving," and "jealousy" are basic intro biology,
and thus unknowable by any other means.
>There are "forces of evolution".
It's gettin' a little preachy in here.
>They are selection, drift, flow, and mutation. Mutation, of course, is
>the ultimate source of all allelic diversity. The frequencies of
>different alleles are affected by selection, drift (accidents), and flow
>(such as immigration from other populations).
I don't need this lesson in basic intro biology. I have no dispute with your
"forces of evolution," as I've made plain in previous posts. I take exception
to your application of this paradigm to explain aspects of human behavior. I
could, by the same token, ask you to take some basic lessons in the social
sciences, but I won't disparage you're intellect. Chalk it up to a difference
>Thus a trait can be explained, evolutionarily, as being a product of
>drift, flow, or selection.
And thus the rub. What you classify as "trait" susceptible to "forces of
evolution" I have some reservation with.
> Only selection can create functionally
>complex traits like the scorpionfly "rape clamp"...
I wouldn't know.
>So, when you reject
>adaptationist explanations out of hand (rather than offering specific
>critiques of a given hypothesis), you are in effect arguing that drift or
>flow is what created the trait--the random, non-selected accumulation of
Since you've already admitted to a lack of evidence for any behavioral
alleles to support the logical implications of your original hypothesis, the
argument is over with.
>That's pretty straight forward, yes?
I should say!
>>>>Selective pressures in the environment. Seeing shadows obviously
>>>>provided early sighted critters (with their crude eyes) with some,
>>>>perhaps slight, survival or reproductive advantage over the blind.
>>>Just so ...
>No, testable. There are living representatives of the various
>fossil-evidenced steps of ancestral eye evolution.
It's still just a story, so distorted by time and ranging across so many
individual, varied lifetimes that it has no real explanatory significance
to the meaning of seeing a parade on Labor Day.
>Blind some of a given
>population's individuals and see if they reliably suffer fitness
I think that depends on the population, neh?
>That would be a reasonable indication that vision increased
>fitness through past generations.
Depends on what you mean by "vision." If complex eyes are more fit than crude
eyes, or no eyes at all, than why are there bad eyes, or crude eyes, or no
>>>>Because, Lenny, individuals aren't passed on.
>>>I could quibble here about exactly who "passed on" if not Aunt Nell, but for
>>>the sake of discussion, we're talking about the functional relevance of a
>>>parsed part to a working system.
>Exactly. Thanks for clarifying your position.
>>>>Genotypes are not, either;
>>>>they're broken up during meiosis.
>>>You would concede they recombine to form functional wholes, now, wouldn't you?
>>>Functional wholes that have prescribed fitness values!
>Yep, collections of well-canalized alleles. Is this supposed to be an
>argument against what I've been saying?!
No, it's meant to counter your characterization of my position.
>>>>Ultimately, although selection acts on
>>>>the individual for whatever net fitness his or her components offer in a
>>>>given environment, only genes are selected for or against.
>>>And so a problem source for the functional adaptationist point of view. The
>>>system from which it was derived (the focal point of natural selection and
>>>what is signified by "fitness") is nothing more than a hodge-podge of
>>>individual traits, each viewed in isolation as a sequence of functional
>There are different intensities of selection on each trait, so that in a
>given selective regime/environment, through deep time, traits are
>selectively disfavored/favored to different degrees (indirectly, through
>their contributions to individuals' fitness).
That problem still presupposes a purpose as a cause. Traits disarticulated
from the system have no purpose. Thus, we never "see" organisms that are just
>>>>[Bryant said:] Some are
>>>>linked, but Mendelian inheritence takes us further than you suggest above.
>>>Why don't you enlighten me as to what you think I've suggested above?
>You talked about your optinion that I shouldn't reducing whole
>organisms to collections of "functional parts," if I recall.
Does Medelian inheritence presuppose a purpose? How does this relate to the
functional conundrum of need before the appearance of a trait?
>>>Or must the baby have traveled the million year road to arrive
>>>at this behavior? Could depression itself be a reflection of the failure of
>>>the self-regulating mechanism to cope with abrupt changes in essential
>>>physical properties, or intrinsic states of being?
>Who exactly are you trying to impress with your assault on plain speaking?
Thought you could follow along. Never mind the details. Imagine a
self-reorganizing system of behavior, one that redesigns it's parts,
properties, inputs, and outputs in order to eliminate deviation from
intrinsic values. Plenty of room for "forces of evolution" here to affect the
appearance of such a system, but it's everyday operation belies nature as
anticipating it's purposes and needs moment-to-moment.
>There is good evidence that baby cries evolved, yes. Most primate
>species have infant cries acoustically similar to that of humans.
Sound production is a complex arrangement of many physical features. I don't
think we need to disentangle the relationship and appearance of each one and
make a functional argument for them. Then again, to argue for the entire
appearance of the acoustical system as responding to a functional need of the
baby to signal mom makes you wonder at the subsequent functions for this same
system: is post-infant speech exaptive?
I concede a vocal tract capable of making similar sounds shared by all
primates. However, the human vocal mechanism differs in several important
and significant ways that relate to the production of speech. The nature,
conditions, and effects of controlling this speech apparatus, even in babies,
is behaviorally contingent and, in my opinion, subject to a self-reorganizing
process inherent to the individual organism.
>Yes, I believe crying serves a (gasp!) function,
More like "crying" serves many functions!
>and that the crying
>behavior and the vocal architecture (including the relevant limbic
>modules) reflect the selective advantage of crying to infants through
This link is where we depart company.
>Care to offer viable alternatives?
The "behavior" and the vocal architecture are not linked, in my opinion, as
>>>>I was asking if your comment about behaviors not being part of a
>>>>phenotype meant that you think they arise from some non-physical entity,
>>>I never made such claim. Your only recourse to a non-functionalist,
>>>non-adaptationist explanation for human behavior can be described at the
>>>very least as unimaginative, something you bewailed over in previous posts!
>Lenny, that's inaccurate. You said that there was a problem with my
>assertion that behaviors are tied to "physical phenotype."
I believe the exact term was "outputs of physical phenotype." I acknowledge
such would be necessary to explain behavior in a functional adaptationist
point of view. However, alternative points of view aren't, as you implied,
motivated from something non-physical. I happen to not choose to define
human behavior in such a way.
I fail to understand what you mean by "inaccurate." If you did not mean to say
that I think behaviors "arise from some non-physical entity" than what did you
mean? If I disagree with your characterization must I then be a bloody
spiritualist? I would simply note that the convocation of "purpose" to explain
the appearance of functions seems more like "an exercise in metaphysics" then
accepting another characterization of behavior different from "outputs of
>If you want to backtrack to explain what you "really meant,"
>be my guest.
Oh, I get it, either I accept your "duelistic/spiritualist interpretation"
as an appellation or acquiesce to your use of "outputs of physical phenotype"
as a working definition for behavior. Excuse me if I decline both.