In article <email@example.com>, rhall at uvi.edu (Richard
> At 1:03 AM -0800 1/30/99, Michael C. Cheney wrote:
> >In article <firstname.lastname@example.org>, rhall at uvi.edu (Richard
> >Hall) wrote:
> >| Natural selection does not appear to favor humans or dolphins of extreme
> >| intelligence...at least there is no evidence that the mean has shifted one
> >| way or the other. It is only sufficient that animals possess sufficient
> >What is your basis for this statement? Are you saying that there is no
> >evidence that the average human intelligence has changed throughout
> >evolutionary history? What time scale are you thinking of, and what
> >evidence is there that it hasn't changed?
>> rlh replies:
>> There is no evidence that human intelligence has increased in the 50,000 -
> 200,000 years of homo sapiens. Do not be fooled by the trappings of
> technology and benefits of economics. Despite the accumulation of
Well, you can also make the counterargument, there is no evidence that it
has not changed. In fact, I think there is considerable evidence that
intelligence has increased in the last 50-200,000 years. You are confusing
intelligence with something completely inherited (which it is clearly
not) and innate; there is a substantial variance in intelligence that is
attributable to environmental factors, and even in biology, development is
abnormal in an abnormal environment. For example, children who grew up in
the wild and found later are incapable of learning language, I think you
know these stories, and the idea is that neural systems which would
mediate language require stimulation, etc.
So take the average cave man, he grows up, in an impoverished environment,
dumb as a rock; the average guy today, who may be identical in biology at
birth, gets an education, and would score higher on any intelligence test,
even those that try not to confound language an education (like those for
pattern solving). Likewise, there are clear associations between early
diet and intelligence as well.
Also, I think the basic argument from ethology is:
different animals specialize in different things, intelligence in
meaningless in this context. For example, food caching in birds is highly
superior to that of humans.
- but the study of intelligence was not developed by ethologists or for
the purpose of comparative animal behavior, it was developed to compare
humans of a particular age with others in the same social group, by
- but ethologists are always making arguments about something being more
adaptive than something else, so at some level they must concede that
there is intelligence and that it is adaptive. The argument that learning
does not effect reproductive success is inane - there was a study in fish
showing that conditioning could affect reproductive success by over 1000
fold. Plus, the conservation of fear conditioning and taste aversion
learning across the phylum clearly shows that it must be associated with
reproductive success. So animals that take longer to exhibit these
features can be regarded as less intelligent than those that do. At the
very least, for example, you must concede that humans are more intelligent
than aplysia. The evidence for this is that humans can acquire complex
information in a single trial whereas aplysia can only acquire a small
subset of this information in many trials. Now whether or not the
intelligence is adaptive for aplysia is not particularly relevant to
whether or not there is something as intelligence (but I can guarantee you
that a smarter aplysia would be a lot better off, since they would be
better at escaping electrophysiologists who might be overfishing them).
- so where am I going with this?
- whether or not there is something as intelligence is independent of
whether or not it is adaptive or associated with reproductive success.
Einstein was more intelligent than the average human but his reproductive
success was average.
- comparative types love to reduce everything to reproductive success but
reproductive success isn't everything. Because there is variability in the
genome you will always have variations in intelligence that are not
necessarily associated with increased fitness
- as far as genes, there are lots of genes you can knockout which clearly
make animals stupid. Most of these experiments are directed at learning,
but this is so confounded with intelligence, they might as well be about
- plus, there is clear evidence that learning ability is adaptive, since
it allows an animal to be better equipped for changes in its niche. In
particular, learning allows it to control predation and diet (clear
evidence of this). So at some level greater learning ability is probably
associated with greater fitness.
Just my 2c worth.
> sophisticated knowledge and the creation of powerful machines, we are just
> as rufus now as then. Humans are social creatures and selection favors
> social skills relevant to fitness. Dolphins are social creatures and the
> presumption probably holds for them as well.
>> Intelligence is basically a preadaptation that allows animals to exploit
> their niche. To suggest extremes in intelligence allowed creatures to
> crawl, fly, or swim out of their niche is a stretch. A position akin to
> saying "We used our intelligence to become a new and improved species,
> Homo intellectualis supremis or Homo retardis extremis"
>> Smart folks often have smart children but does that translate into
> increased fitness? The idea that intelligence is the dominating element in
> reproductive success, that intelligence is inherited, that extremes in
> intelligence are a criteria for speciation cannot be easily supported. A
> population is comprised of individuals with a distribution of
> characteristics but "intelligence" is not a straight forward expression of
> a few genes. If we could prove that a set of conditions applied to a
> population altered some statistically relevant aspect of the population's
> intelligence quotient in an inheritable, reproducible manner then I would
> probably recant. But, we can't.
>> 1. Testing intelligence is problematic and we would need standardized
> testing over many, many generations to form conclusions about changes in
> IQ. I took an IQ test when I was 12 years old after which my folks called
> me an underachiever, sold my string of ponies, took me out of little
> league, and made me take dancing lessons and go to Sunday school. I guess
> they really did know something about natural selection ;-).
>> 2. Cross species testing is frankly improbable beyond anecdotes...my dog
> is smarter than your cat. That lizard hasn't a clue about the nutritional
> value of raisins. My aren't those dolphins smart, do you think they would
> watch and learn as much from TV as the average walrus? Is the
> "intelligence" of a bison the reason it does better in the open range than
> a long horn steer? Nonsense. Irrelevant.
>> 3. Population geneticists have used natural selection to select specific
> behaviors such as geotrophisms in fruit flies (forming populations of flies
> that orient in different ways toward gravity.) But as I recall selection
> acted on variations in gravity sensing.) The analogy would be using
> selection to form populations with a high incidence of a specific visual
> defect that influences behaviors.
>> 4. Obviously, a severely retarded creature is at disadvantage in passing
> genes to the next generation unless thrown into a clad of severely retarded
> creatures. Domestic turkeys do not fare well in wild populations. Wild
> populations of turkeys quickley learn to be scarce during hunting season,
> but does than mean we are selecting for smarter populations of turkeys by
> hunting them and stupid turkeys by raising them?
>> 5. It is easy to look at the history of humans and to form opinions about
> how much smarter we appear now compared to those silly Egyptians and
> Sumerians. Technology has improved. In some parts of the world, literacy
> rates have improved. But do either provide evidence that intelligence
> measures (which we cannot agree on) have improved? How many egyptians knew
> how to design pyramids or make medicines compared to how many egyptians
> know how to repair a computer or create a new designer drug? I consciously
> avoided mention of North Americans, but well, our senate is pretty
> comparable to senates in ancient Rome and politics is still politics and
> sex is still sex subject to redefinition in courts and polls.
>> Natural selection seems to favor the mean most of the time. When
> circumstances change, selection favors better adaptations. Intelligence
> does not seem to be the critical factor perpetuating our species today.
> > -mike
> >Michael Cheney cheney at ucla.edu>> Richard Hall
> Comparative Animal Physiologist
> Division of Sciences and Mathematics
> University of the Virgin Islands
> St. Thomas, USVI 00802
>rhall at uvi.edu