🚀 go-pugleaf

darice@yoyo.cc.monash.edu.au (Fred Rice) writes:

>I was wondering, is there an evolutionary explanation for the great
>capacities humans have to think?  I'm thinking about things like our
>ability to do advanced mathematics, for instance.  There is no
>evolutionary survival advantage in being able to solve differential
>equations, for instance.  If this is the case, then *why*, in
>evolutionary terms, can we do such things?

Maybe you should rephrase the question "What are the forces which have
pushed/pulled human intelligence up to the level where it has given
humans the ability to do such abstract things as differential 
equations?"

Various hypotheses have been put forward to try to explain how in 
just a few million years a species went from being "apes" to humans.
But from what I (definitely a non-expert) have seen there does not
seem to see widespread agreement.

     So baring in mind my non-expertise here is the explanation for
the main force which is the best I think I have heard:-

   Several million years ago continental drift moved the continents
   into positions where their climate became ultra sensitive to any 
   changes in the Earth's rotation (Milankovich cycles).  These changes
   resulted in a regular cycle of Ice Epochs which themselves were 
   divided into a series of ice age followed by warmer interglacial.
   The current Ice Epoch has lasted since (I forget, maybe 1 or 2 million
   years ago),  and it has consisted of ice ages of about 100,000 
   years followed by interglacials of up to 10 to 12 thousand years.

        The present interglacial has lasted about 12,000 years, which
   is longer than any other recent one.  [This is partly why in the 
   1970's there was all the fuss about "Is the next ice age about to 
   start"].

       The result of all of this on the climates of the different 
   regions of the Earth was that there were regular shifts from warmer
   to cooler, wetter to drier etc and back again.  Naturally as these
   shifts only lasted between 10,000 and 100,000 years animals and
   plants did not always have time to properly adapt to an environment
   before the climate changed again.

       It has been argued that during the long 100,000 periods humans
   branched into different subspecies or races and some were more 
   successful than others at specialising.  Once the climate changed 
    again many/most of the specialist were at a disadvantage to the 
   less specialist races and were more likely to die out.  
      
        A premium was put on adaptability and it was modern humans
    with their mental, not physical, specialisation which "won".
    Note though that without the repeated climate changes one of the
    less intelligent competitors would have driven them to extinction.


> Fred Rice
> darice@yoyo.cc.monash.edu.au   

further reading
  Imbrie and Imbrie, "the ice age", or some similar title.
  for a recent presentataion of the therory see
    "Children of the Ice" by John and Mary Gribbin.

In article <Bzrn4H.GMq@newcastle.ac.uk> w.p.coyne@newcastle.ac.uk writes:

	Material relating to  climate  and its impact on human evolution
deleted

>       It has been argued that during the long 100,000 periods humans
>   branched into different subspecies or races and some were more 
>   successful than others at specialising.  Once the climate changed 
>    again many/most of the specialist were at a disadvantage to the 
>   less specialist races and were more likely to die out.  
>      
>        A premium was put on adaptability and it was modern humans
>    with their mental, not physical, specialisation which "won".
>    Note though that without the repeated climate changes one of the
>    less intelligent competitors would have driven them to extinction.
>

	If memory serves, the second most numerous  primate is the
baboon,  who are also  pretty bright  and much  less dependent on
a  specific environment than apes like  chimpanzees  or many
monkey species.

							James Nicoll

In article <Bzrn4H.GMq@newcastle.ac.uk> w.p.coyne@newcastle.ac.uk writes:
 ...
>     So bearing in mind my non-expertise here is the explanation for
>the main force which is the best I think I have heard:-
>
>   Several million years ago continental drift moved the continents
>   into positions where their climate became ultra sensitive to any 
>   changes in the Earth's rotation (Milankovich cycles).  These changes
>   resulted in a regular cycle of Ice Epochs which themselves were 
>   divided into a series of ice age followed by warmer interglacial.
>   The current Ice Epoch has lasted since (I forget, maybe 1 or 2 million
>   years ago),  and it has consisted of ice ages of about 100,000 
>   years followed by interglacials of up to 10 to 12 thousand years.
...
>       It has been argued that during the long 100,000 periods humans
>   branched into different subspecies or races and some were more 
>   successful than others at specialising.  Once the climate changed 
>    again many/most of the specialist were at a disadvantage to the 
>   less specialist races and were more likely to die out.  
>        A premium was put on adaptability and it was modern humans
>    with their mental, not physical, specialisation which "won".
>    Note though that without the repeated climate changes one of the
>    less intelligent competitors would have driven them to extinction.
>> Fred Rice
>> darice@yoyo.cc.monash.edu.au   

I think this theory (nicely explained here) is mainly due to William
Calvin <wcalvin@milton.u.washington.edu>, an occasional contributor
here.  See his book, The Cerebral Symphony.

..

minsky@media.mit.edu (Marvin Minsky) writes:

>I think this theory (nicely explained here) is mainly due to William
>Calvin <wcalvin@milton.u.washington.edu>, an occasional contributor
>here.  See his book, The Cerebral Symphony.

Thanks.  Actually, it is the book after that, THE ASCENT OF MIND: Ice Age
Climates and the Evolution of Intelligence (Bantam 1990).
    William H. Calvin   WCalvin@U.Washington.edu

wcalvin@stein.u.washington.edu (William Calvin) writes:

>minsky@media.mit.edu (Marvin Minsky) writes:

>>I think this theory (nicely explained here) is mainly due to William
>>Calvin <wcalvin@milton.u.washington.edu>, an occasional contributor
>>here.  See his book, The Cerebral Symphony.

>Thanks.  Actually, it is the book after that, THE ASCENT OF MIND: Ice Age
>Climates and the Evolution of Intelligence (Bantam 1990).
>    William H. Calvin   WCalvin@U.Washington.edu

  Had you publicised the theory before 1990 in articles, talks or the 
media?   Or was yours an expansion of an existing well publicised
theory of the effects of climate on human evolution..  
 
   I ask because "Children of the Ice" by John and Mary Gribbin
was also published in 1990.  I think sometime in the late 80's John
Gribbin did a radio series for the BBC of 10 minute episodes where
he explained this theory of the importance of climatic interaction with
humans.  
   
    HIs discussion of the settlement of Greenland by the Vikings
during a warm period 
lasting a few centuries, and then its destruction caused by the colder
weather of the 15th century was memorable.   The phrase "adapt or die"
was very appropriate because the settlers could have survived if they
had discarded their European lifestyle and agriculture and adopted the
eskimo way of life (maybe some of them did).

w.p.coyne@newcastle.ac.uk writes:

>  Had you publicised the theory before 1990 in articles, talks or the 
>media?   Or was yours an expansion of an existing well publicised
>theory of the effects of climate on human evolution..  
> 
>   I ask because "Children of the Ice" by John and Mary Gribbin
>was also published in 1990.  I think sometime in the late 80's John
>Gribbin did a radio series for the BBC of 10 minute episodes where
>he explained this theory of the importance of climatic interaction with
>humans.  
>   
>    HIs discussion of the settlement of Greenland by the Vikings
>during a warm period 
>lasting a few centuries, and then its destruction caused by the colder
>weather of the 15th century was memorable.   The phrase "adapt or die"
>was very appropriate because the settlers could have survived if they
>had discarded their European lifestyle and agriculture and adopted the
>eskimo way of life (maybe some of them did).

 
The idea (of climate change affecting human evolution) is neither original to
Gribbin or me, it goes back at least to Darwin, who in the ORIGIN OF SPECIES
said, "The action of climate seems at first sight to be quite independent
of the struggle for existence; but in so far as climate chiefly acts in
reducing food, it brings on the most severe struggle between individuals,
whether of the same or of distinct species, which subsist on the same kind
of food.  Even when climate, for instance extreme cold, acts directly, it
will be the least vigorous, or those which have got the least food through
the advancing winter, which will suffer the most."
        THE ASCENT OF MIND is not particularly concerned with what has
happened since the end of the last ice age about 12,000 years ago; my one 
brief mention of the Iceland-Greenland Norse saga at page 107 came from 
John and Mary Gribbin's excellent article in NEW SCIENTIST of 
20 January 1990, and was inserted into the galley proof for ASCENT, 
which came out later that year.  ASCENT proceeds from the observation
that three things happened starting about 2-2.5 Mya:  brain
enlargement, prolific stone toolmaking, and the ice ages; it asks
what might the relations between them.
        ASCENT is particularly about the process whereby ice margin 
fluctuations serve to select for certain traits; I'm a neurophysiologist 
interested in the hominid brain enlargement/reorganization problem.  
Any originality of ASCENT lies in those areas, not in calling attention 
to the role of climate change in speeding evolution which has been 
widespread in paleoanthropological circles for some time.
 
    William H. Calvin   WCalvin@U.Washington.edu

w.p.coyne@newcastle.ac.uk writes:

>darice@yoyo.cc.monash.edu.au (Fred Rice) writes:
>
>>I was wondering, is there an evolutionary explanation for the great
>>capacities humans have to think?  I'm thinking about things like our
>>ability to do advanced mathematics, for instance.  There is no
>>evolutionary survival advantage in being able to solve differential
>>equations, for instance.  If this is the case, then *why*, in
>>evolutionary terms, can we do such things?
>
>Maybe you should rephrase the question "What are the forces which have
>pushed/pulled human intelligence up to the level where it has given
>humans the ability to do such abstract things as differential 
>equations?"

Human evolution is a complex process that includes the development of
also other weird characteristics than the big brain, for instance upward
gait and nakedness. To me it seems that by far the most coherent
explanation is that during the time their brain started to evolve larger,
our ancestors were living at the seashore. It is rather typical for sea
mammals that the size of their brains is larger in relation to body size
than with terrestrial mammals of the same weight. I doubt that dolphins
could solve differentials, but they are the only animals that have as big
brains as we do, and they are also known to be rather smart.
There are at least two reasons why a mammal that turns (partly) aquatic
would develop a large brain. First, neoteny is a typical characteristic
of aquatic mammals, and this results kind of automatically in larger
brains, because the foetus always has relatively larger brains than the
adult. Second, seafood is rich in some fatty substances that are
essential as building blocks of the brain, while these substances are
rather scarce in the food available in terrestrial environments. In
savannah or forest, therefore, an exessively big brain is an
energetically expensive luxury that would be selected against, while in a
marine environment it would not be such a burden and could grow beyond
the limits of immediate need.
The climate changes have certainly played their part in initiating the
process by driving the future humans away from the shrinking rain
forests. But it was the life at sea that caused the radical anatomical
and physiological changes that make us so different from the rest of the
primates. The evidence for this hypothesis is summarized in two books by
E. Morgan: The Aquatic Ape (1982 or thereabouts) and The Scars of
Evolution (1990).
I have been wondering why this theory is so seldom mentioned in
speculations about our evolution. If any of the experts who have been
contributing to this discussion could give me an answer, I would be very
pleased indeed.

Hanna Tuomisto
hantuo@utu.fi

Hanna Tuomisto <hantuo@utu.fi> writes:

>Human evolution is a complex process that includes the development of
>also other weird characteristics than the big brain, for instance upward
>gait and nakedness. To me it seems that by far the most coherent
>explanation is that during the time their brain started to evolve larger,
>our ancestors were living at the seashore. It is rather typical for sea
>mammals that the size of their brains is larger in relation to body size
>than with terrestrial mammals of the same weight. I doubt that dolphins
>could solve differentials, but they are the only animals that have as big
>brains as we do, and they are also known to be rather smart.
>There are at least two reasons why a mammal that turns (partly) aquatic
>would develop a large brain. First, neoteny is a typical characteristic
>of aquatic mammals, and this results kind of automatically in larger
>brains, because the foetus always has relatively larger brains than the
>adult. Second, seafood is rich in some fatty substances that are
>....
>primates. The evidence for this hypothesis is summarized in two books by
>E. Morgan: The Aquatic Ape (1982 or thereabouts) and The Scars of
>Evolution (1990).
>I have been wondering why this theory is so seldom mentioned in
>speculations about our evolution. If any of the experts who have been
>contributing to this discussion could give me an answer, I would be very
>pleased indeed.

>Hanna Tuomisto
>hantuo@utu.fi

I'm a fan of an aquatic phase in hominid evolution (see THE RIVER THAT
FLOWS UPHILL) but I'd place it rather early, between 6 and 4 Mya; there
was a meeting in 1990 published under the title THE AQUATIC APE: FACT OR
FICTION in 1992, editor Machteld Roede, from one of the smaller European
publishers. 

The more noticeable aspects of brain enlargement and reorganization (c.f.,
Dean Falk's BRAINDANCE, 1992) begin only about 2.5-2.0 mya.  Prime refs
for social intelligence is the Byrne and Whitten MACHIEVALLIAN
INTELLIGENCE (Oxford 1988) and Nick Humphrey's books, e.g., A HISTORY OF
THE MIND (1992), with Frans de Waal's books CHIMPANZEE POLITICS (1982) and
PEACEMAKING AMONG PRIMATES (1989) absolutely essential.
    William H. Calvin   WCalvin@U.Washington.edu

In article <Bzrn4H.GMq@newcastle.ac.uk> w.p.coyne@newcastle.ac.uk writes:
}darice@yoyo.cc.monash.edu.au (Fred Rice) writes:
}
}>I was wondering, is there an evolutionary explanation for the great
}>capacities humans have to think?  I'm thinking about things like our
}>ability to do advanced mathematics, for instance.  There is no
}>evolutionary survival advantage in being able to solve differential
}>equations, for instance.  If this is the case, then *why*, in
}>evolutionary terms, can we do such things?
}
}Maybe you should rephrase the question "What are the forces which have
}pushed/pulled human intelligence up to the level where it has given
}humans the ability to do such abstract things as differential 
}equations?"

Bad example.  Catching a branch after a free-fall requires the
"unconscious" solution of a DE.  Catching a ball is a complicated
set of equations.  Now, being able to express it AS equations is recent,
but the ability to solve them isn't....

m23364@mwunix (James Meritt) writes:

>Bad example.  Catching a branch after a free-fall requires the
>"unconscious" solution of a DE.  Catching a ball is a complicated
>set of equations.  Now, being able to express it AS equations is recent,
>but the ability to solve them isn't....

All animals seem to have the ability to make at least one particular kind
of trajectory calculation, also involved in catching a ball:  that of
judging whether an approaching object will hit their head.  It produces
the blink replex, and cognitive-level abilities need not be invoked (it's
a brainstem-level reflex, based on looming).

Now throwing a projectile, and estimating its trajectory in advance during
"get set", is indeed a good candidate for a cognitive mechanism.  All of
the ballistic movements (kicking, clubbing, throwing, hammering -- even
spitting) require lots of advance planning; feedback arrives too late to
do any good, so "get set" must create a complete movement command
sequence, start to finish.  In the case of throwing to a target (as
opposed to threat throws, where accuracy is not important), precision
timing becomes very important: hitting a rabbit-sized target from the
length of a car requires getting the projectile release within a 5
millisecond launch window.

I've discussed this at some length, as a candidate for the sequencing
abilities that separate humans from apes, in various of my books, most
recently in chapters 7 and 8 of THE ASCENT OF MIND (Bantam 1990).
    William H. Calvin   WCalvin@U.Washington.edu
    University of Washington  NJ-15
    Psychiatry & Behavioral Sciences
    Seattle, Washington 98195 FAX:1-206-720-1989

darice@yoyo.cc.monash.edu.au (Fred Rice) writes:

>I was wondering, is there an evolutionary explanation for the great
>capacities humans have to think?  I'm thinking about things like our
>ability to do advanced mathematics, for instance.  There is no
>evolutionary survival advantage in being able to solve differential
>equations, for instance.  If this is the case, then *why*, in
>evolutionary terms, can we do such things?

  New Scientist (5-Dec-92) had a seven page supplement "The great Brain 
race", which was one of the many supplements they have had on the Secret
Life of the Brain.

  It is relevent to this discussino but I am sending it under a new
subject heading  = brainsize - the great brain race.

But I thought I would summary the questions it answers so anyone 
reading this subject who is interested will not miss it.

   Why did mammals evolve large brains 250 Ma?
   Why did mammals evolve even larger brains 65 Ma.?
   Why did primates evolve brains large compared to other mammals?
   How do primates grow such large brains?
   Why did humans evolve such large brains compared to primates?
   Is size the only way humans brains differ?

In article <1hpvrpINNsam@shelley.u.washington.edu>, wcalvin@stein.u.washington.edu (William Calvin) writes:
|> m23364@mwunix (James Meritt) writes:
|> 
|> >Bad example.  Catching a branch after a free-fall requires the
|> >"unconscious" solution of a DE.  Catching a ball is a complicated
|> >set of equations.  Now, being able to express it AS equations is recent,
|> >but the ability to solve them isn't....
|> 
|> All animals seem to have the ability to make at least one particular kind
|> of trajectory calculation, also involved in catching a ball:  that of
|> judging whether an approaching object will hit their head.  It produces
|> the blink replex, and cognitive-level abilities need not be invoked (it's
|> a brainstem-level reflex, based on looming).

Yes, the ability to catch things does not require "solution" of a DE 
or set of DE's in the normal sense of the word, you just need a good
feedback control system ... you may need to tweak the gains depending
on what your catching (maybe adaptive feedback control is the more correct
term) but to say that one must "solve" a complex set of DE's is misleading.

|> Now throwing a projectile, and estimating its trajectory in advance during
|> "get set", is indeed a good candidate for a cognitive mechanism.  All of
|> the ballistic movements (kicking, clubbing, throwing, hammering -- even
|> spitting) require lots of advance planning; feedback arrives too late to
|> do any good, so "get set" must create a complete movement command
|> sequence, start to finish.

While throwing activities are better candidates for cognitive mechanisms
I still don't think they *require* anything more than the ability to
interpolate or extrapolate from past experience.

Larry Edwards

ledwards@leland.Stanford.EDU (Laurence James Edwards) writes:

>Yes, the ability to catch things does not require "solution" of a DE 
>or set of DE's in the normal sense of the word, you just need a good
>feedback control system ... you may need to tweak the gains depending
>on what your catching (maybe adaptive feedback control is the more correct
>term) but to say that one must "solve" a complex set of DE's is misleading.

>|> Now throwing a projectile, and estimating its trajectory in advance during
>|> "get set", is indeed a good candidate for a cognitive mechanism.  All of
>|> the ballistic movements (kicking, clubbing, throwing, hammering -- even
>|> spitting) require lots of advance planning; feedback arrives too late to
>|> do any good, so "get set" must create a complete movement command
>|> sequence, start to finish.

>While throwing activities are better candidates for cognitive mechanisms
>I still don't think they *require* anything more than the ability to
>interpolate or extrapolate from past experience.

>Larry Edwards

Agreed.  What's so nice about throwing and the other ballistic movements
(hammering, kicking, clubbing, spitting) is that they may share a common
neural machinery for fancy sequences.  It is already known that the core
of language cortex (see the Ojemann article in 1983 Behavioral and Brain
Sciences) has a sequencing specialization, that it handles both auditory
sequences and movement production sequences.
	So it may be that evolutionary pressures for one sequencing task
bring along some of the others for free.  Certainly this hypothesis is
requires at some point for music and dance, i.e., they must be secondary
uses of neural machinery that was primarily shaped up by other kinds of
usefulness, such as language or planning ahead.  As I have proposed (THE
ASCENT OF MIND is the most recent version), any of these various skills
might have helped improved the others -- but precision throwing for
predation has a particularly nice payoff in terms of reproductive success
during hominid evolution.  That's why throwing is so interesting to one
interested in higher intellectual functions such as language and plan-ahead.
    William H. Calvin   WCalvin@U.Washington.edu
    University of Washington  NJ-15
    Seattle, Washington 98195 FAX:1-206-720-1989