Jennifer M. Cannistra
The Origin, Evolution, and Inevitability of Human Intelligence

	Throughout history, the evolution of human intelligence has
fascinated mankind.  This age old debate has challenged the great
minds of the world from thousands of years ago to the present, and
individuals have long debated and searched for a tangible conclusion.
Unfortunately, our present knowledge does not provide absolute
answers.  However, several studies support the similar conclusion that
early human intelligence emerged during the Ice Age and progressively
increased with evolution.  Furthermore, one theory concludes that if
life emerges on a planet, intelligent life will inevitability surface
and continually evolve.  Over the last century society has expanded
questions and studies concerning intelligent life from our earth to
the entire universe, and at a conference in Green Bank, West Virginia
in 1961, leading scientists concluded that there is strong evidence
intelligence will emerge on life bearing planets.  Therefore, this
supports the theory that the evolution of intelligence on Earth is not
unique, and we are not alone in our universe.

Part I: The Origin and Evolution of Human Intelligence

Where was the beginning, over the course of billions of years, of
human intelligence on our planet, and how did this intelligence arise
on the Earth?  One theory suggests that rapid fluctuations in climate
during the last ice age eleven thousand years ago may have led to
greater intellectual resources in early humans.  During this time
period, even though the average temperature was much lower than it is
today, the climate still had abrupt fluctuations, sometimes lasting
for centuries.  Specifically, in the space of a few decades, the
temperature increased thirteen degrees Fahrenheit and rainfall jumped
fifty percent (Calvin p. 103).  Entire forests vanished from these
drastic jumps in temperature and rainfall, and cold periods began just
as suddenly.  The hominid brain did not rapidly expand until the ice
age began, 2.5 million years ago, and the connection between such
fantastic events is most likely not coincidental.  Because early
humans would have needed intelligence to survive these changes, I
believe there is a strong possibility that human intelligence evolved
during this era.  Without innovative reasoning and problem solving
abilities, the early humans would not have been able to procure food
and shelter in such an adverse, changing environment.  Therefore
environmental fluctuations may have mandated new mental abilities.

One of the most notable human additions during the ice age was the
capacity for human language, often considered the most defining
feature of human intelligence.  As William Calvin argues, "without
syntax-the orderly arrangement of verbal ideas-we would be little more
clever than a chimpanzee" (p. 102).  Specifically, Calvin explains
that the switch from apes' symbolic repertoire to the invention of
syntax directly correlates with the higher intelligence of our
species.  Whereas chimpanzees use about three dozen different
vocalizations to convey the meaning of three dozen different meanings,
humans use the same three dozen vocalizations in combination with each
other to make meaningful words.  Calvin believes that this transfer
from "one sound/one meaning" to a sequential combination of sounds for
communication instigated ape-to-human evolution (p. 102).  Since
language emerged during the Ice Age, and because I feel communication
goes hand in hand with intelligence, I believe that this time period
contains the roots of our intellectual origin.  This new world of
communication produced a setting conducive for greater intelligence,
allowing innovative decision making and opinions to emerge.  As a
result, humans survived the environmental vicissitudes thrown upon
them.

Many researchers parallel the emergence of human intelligence with the
evolutionary ladder.  In a quantitative study noted in
"Extraterrestrial Life," Neal Evans attempts to locate this route by
counting the genetic information stored in the DNA of various
organisms (p. 86).  In this study, he defines intelligence by the
extent of information stored in the organism, and he uses the amount
of genetic information stored in the DNA as a touchstone.  By plotting
the number of bits of information in the DNA of organisms versus the
time they first appeared on Earth, the data indicates that over time
the increasing diversity of life led to species with more
intelligence.  Therefore, in a broad sense, as species became more
complex, they concurrently became more intelligent.  However, large
amounts of junk DNA, irrelevant strands not coding for a specific
protein, cast a shadow on this method, clouding its validity.
Furthermore, the results indicate that less intelligent organisms did
not disappear, such as blue-green algae and cockroaches, and therefore
not all evolutionary lineages increased their intelligence over
successive years.  Moreover, even though cockroaches have evolved
without a great deal of intelligence, they are still a highly
successful species, thus suggesting that intelligence is not a
requirement for organisms to flourish.  Although doubts surround this
approach used to outline the progression of intelligence, evolution on
earth has increased the mean complexity of organisms over time, and
assuming intelligence is an advantageous trait, as has seemed to be
the case on Earth, it is plausible that intelligence would also
increase over time.

In addition, another quantitative approach outlining the evolution of
human intelligence is the analysis of the cerebral cortex, the
component of the brain most strongly linked to intelligence, of
various species.  A flattened human cortex occupies four sheets of
typing paper, whereas a chimpanzee's cortex fits on one sheet, a
monkey's on a postcard, and a rat's on a stamp (Calvin p. 101).
Therefore, many scientists believe the larger the surface area of the
cerebral cortex, the more intelligent the species.

In Dragons of Eden, Carl Sagan suggests four possible reasons why
human intelligence did not appear until a few million years ago, only
a small percentage of the Earth's age.  First, the human brain is much
more massive than that of our ancestors, almost entirely filling its
skull.  He proposes that the increase in mass may parallel an increase
in intelligence.  Second, the human brain has a much smaller body to
brain ratio, indicating the brain is a larger percentage of a body's
total mass.  To illustrate, whereas humans have a ratio of forty-five,
fossils of Homo erectus, considered the predecessor to our race, have
a much higher ratio of sixty-five (Sagan p. 101).  Third, the human
brain contains certain functional units, such as large frontal and
temporary lobes, for the first time.  Specifically, these components
control human thought, and people who have had prefrontal lobotomies
often do not realize that they have control over their own lives.
Therefore, lower mammals and reptiles, lacking extensive frontal
lobes, may not grasp this concept of individuality, a main essence of
human intelligence.  Last, the human brain contains a great deal more
neural connections, considered by many neurobiologists to be the
active elements in brain functions.  Although Sagan implies that these
quantitative changes led to human intelligence, he also realizes that
his theories are highly speculative.  I feel that this quantitative
data cannot be ignored, but I also do not think these conclusions are
definitive.  At the present time we cannot distinguish which of these
possibilities are correct and which are irrelevant.  Therefore, I feel
we must be cautious, not putting extended emphasis on these
conclusions.

The previous theories on the origin and evolution of human
intelligence present a wide variety of opinions and speculations.  Do
these studies ultimately reach a conclusion?  Because this topic is
controversial and intelligence is an intangible concept, it is
difficult to find absolute answers.  However, from our experience on
Earth we can conclude that intelligence does aid the survival and
adaptation to changing environments.  Therefore, during the Ice Age,
increased intelligence was necessary in order to cope with such
extreme fluctuations in the environment.  The emergence of language,
considered by many to be a definitive feature of human intelligence,
helped procure food, water, and shelter, and therefore communication
directly correlates with the evolution of our intelligence.
Furthermore, I feel that when the quantitative studies concerning
brain, DNA, and cortex size are analyzed together, they all seem to
point in the same direction, outlining the evolution of human
intelligence.

Part II: The Inevitability of Human Intelligence

	Human beings have often viewed intelligence evolution as a
ladder, with each rung reaching higher levels, until, after millions
of years, we have reached the final destination: modern humans.  The
human race, on a whole, believes itself to be more intelligent than
other animals and that levels of intelligence parallel the
phylogenetic scale, moving from invertebrates to lower vertebrates,
mammals, primates, and at last, considered the pinnacle of this
process, the human race.  In the search to define intelligence and
find its origin on earth, a larger debate has surfaced: are humans
alone sentient or rather is this abstract quality a pervasive
characteristic of life as we know it?

In his essay "Intelligence in Evolution," Nicholas Mackintosh argues
that levels of intelligence do not linearly progress up the
evolutionary scale and that all living creatures are sentient (p. 27).
He considers intelligence a "diverse or heterogeneous array of
processes, operations, and skills," and he feels that many of these
skills are widespread, common to essentially all vertebrates (p. 28).
Although recognizing that some operations are specialized for
particular purposes and are much less evenly distributed among
species, he ultimately feels that advanced forms of intelligence are
not only found in higher animals.  For example, Mackintosh states that
certain species, such as Clark's nutcracker, a bird living in the
Rocky Mountains with a brain weighing less than ten grams, outperforms
the human race in spatial memory.  Specifically, feeding off pine
seeds that are only abundant in the fall, the nutcracker hides
approximately thirty thousand seeds, necessary for relocation over the
next six months in order to survive.  Observation shows that the bird
finds more than half of these seeds, and laboratory experiments reveal
this ability far exceeds that of humans, who must laboriously record
where the bird has hidden the seeds.  Mackintosh presents a common
view that true intelligence "is about understanding the world not just
perceiving it; predicting the future; adjusting to changing
circumstances; solving problems; drawing inferences; and reasoning,"
and argues that many animals also achieve these goals (p. 30).
However, even if we assume that animals do possess intelligence, I
believe that humans are obviously at a more advanced level than other
organisms on our planet.  I feel there is a distinction between the
intelligence of human beings and of other surrounding creatures, and
therefore I do not agree with Mackintosh's implication that all
organisms essentially possess the same intelligence level.  As all
words and methods of measuring intelligence are relative, the term
"sentient" is an intangible concept.  However, because I feel a
difference does exist between humans and other organisms, I would not
apply this term, as Mackintosh has done, to all creatures.

Furthermore, language is often considered the most defining feature of
human intelligence, and it is important to recognize that other
species on earth also possess the ability to communicate.  To
illustrate, mankind has long attempted to initiate communication with
animals, often times a chimpanzee, but until twenty years ago,
scientists only attempted this through vocalization.  Because the
chimp could only learn a minimal number of words, the early studies
concluded that this species was incompetent in communication.  The
realization by two psychologists, Beatrice and Robert Gardner from the
University of Nevada, that the pharynx and the larynx of the chimp are
unsuitable for human speech, however, opened a whole new world of
research.  Reasoning that the chimpanzees may have substantial
language abilities which cannot be expressed because of the
limitations of their anatomy, they attempted to teach chimpanzees sign
language.  This approach was highly successful, as their subjects now
possess vocabularies equivalent to a basic knowledge of our language.
If language is one of the most important requirements for
intelligence, where does this realization place this species?  I
recognize that chimpanzees possess a certain degree of intelligence
because of their ability to communicate, learn new concepts, and offer
opinions through sign language, but, similar to my argument against
Mackintosh's theory, I feel that there is a concrete difference in the
levels of intelligence between the human race and the chimpanzees.  As
Carl Sagan questions in Dragons of Eden, why are there no non-human
primates with an existing complex gestural language?  He suggests that
"humans have systematically exterminated those other primates who
displayed signs of intelligence...and we may have been the agent of
natural selection in suppressing the intellectual competition"
(p. 124).  If this is the case, I agree with his conclusion that by
teaching gestural language to chimpanzees, we are beginning a belated
attempt to make amends.  Therefore, perhaps in the future we will
witness the full extent of their intelligence and language ability.

Contrary to all previous theories, George Simpson, a paleontologist at
Harvard University, does not agree that intelligence is an inevitable
result of evolution.  Instead, he believes that even slight changes in
our earlier history would profoundly affect all descending organisms
through the succeeding millions of generations (p. 267).  Therefore,
he feels that even the enormous diversity of life, with millions of
species, represents only a fraction of possible forms.  Furthermore,
he believes that existing species, including Homo sapiens, would be
different if any part of our evolutionary history or environment had
taken another path.  Humans emerged after a very precise sequence of
events covering over two billion years, and Simpson believes all
evolution involves similar amounts of chance.  In his book This View
of Life, Simpson acknowledges that intelligence is a spectacular
adaptation that therefore has a strong rate of survival.  As a result,
he concludes that intelligence, once it appears, would be favorable by
natural selection on a variety of planets.  However, he believes that
events leading to the creation of a thinking creature on earth "have
been so extremely special, so very long continuous, so incredibly
intricate that I have been able hardly to hint at them here" (p. 257).
I disagree with his approach, and instead I feel that intelligence is
a natural sequence in the process of evolution, regardless of the
chosen path.  Although different routes may be taken during evolution,
I feel that life will inevitability reach the same end result:
intelligence.  To the best of our knowledge, intelligence is
beneficial to life, and therefore I feel natural selection will favor
the development of intelligent, self-conscious beings.  If life forms
on other planets, just as blue-green algae emerged on Earth 3.5
billion years ago, I believe intelligent life will inevitably surface.

Part III: Future Evolution

As scientists debate and theorize about the past, they cannot help but
also look to the future and ponder an inevitable question: has
evolution stopped with the emergence of human beings?  Has Earth seen
the highest level of intelligence in one of its species?  Humans often
consider evolution a journey leading up to the creation of man,
similar to a mountain filled with all living organisms leading up to
the human race at the top.  At this apex, man can look down at all of
his predecessors and bask in his greatness.  An important question to
ponder is, will he ever have anything above him?  Although the answer
is still highly speculative, it is unlikely that humans are the end of
an evolution process that has been continuing for billions of years.
When considering future evolution of the human race, an important
consideration is the distinction between microevolution, changes
within and between breeding populations over time, and macroevolution,
the rise and fall of identifiable species.  Many experts say that
geographic isolation usually triggers the rise of new species, and
since complete isolation from the rest of humanity does not commonly
exist in today's developed society, human micro-evolution has ended in
the modern world (p. 1 Small).  However, mankind, just as throughout
the history of life on Earth, may encounter mutations and experience
extreme environmental changes.  Because these factors have caused
evolution in the past, they will also influence future evolution.
Therefore, humans cannot consider themselves an exception to the
evolutionary process.

Even so, humans do possess a new influence on evolution not present in
earlier species: the power of conscious control.  New technological
intervention working to overcome effects of disease, famine, genetic
defects, and natural disaster influences the composition of the gene
pool.  Specifically, the control of smallpox epidemic shows how
man-made vaccinations and cures have changed the human race and
eliminated the inescapable choke hold some deadly diseases have had on
our society.  Millions of individuals died from smallpox, and because
many met their tragic fate before the reproductive age, they did not
pass their genes onto future generations.  Today, since medicine has
wiped smallpox off the planet, individuals who may have faced the
consequence of this disease live and reproduce, thus contributing to
the human gene pool.  Therefore, these individuals now have a part in
human evolution, and thus this path will subsequently vary from its
previous route.

Part IV: Intelligence on Other Planets

Over the last century, society has taken the analysis, debate, and
studies of intelligent life from a focus on earth to a focus on the
extra-terrestrial.  After spending years analyzing evolution of
intelligence on Earth, questioning the role of humans in this process,
and speculating on future evolution, astronomers have changed these
questions to universal onesE Does intelligent life exist on other
planets?  Are humans alone in our universe, or will our earth someday
come in contact with extra-terrestrial creatures?  In 1961, a group of
eleven scientists met in Green Bank, West Virginia to discuss the
possibility of contacting other worlds.  At this conference, Frank
Drake presented an equation listing seven factors that would determine
how many civilizations might be trying to contact Earth, and factor
number five concerns the fraction of life bearing planets on which
intelligence emerges.  The strongest argument in the debate for this
factor is the tendency of life that "drives it into every nook and
cranny of the environment where, by some marvel of adaptation or
ingenuity, sustenance can be found" (Sullivan p. 256).  Specifically,
using Earth as an example, fins have evolved for life in water, wings
have developed for flight in the sky, and algae have survived in the
scalding water of hot springs.  Over billions of years, evolution has
spread life into all areas, from miles under the sea to the high
atmosphere of Earth.

However, because Simpson, as stated earlier, considers the path to
human evolution a long string of haphazard chances, he proposes that
if there are any intelligent beings in our universe, they are at a
great distance from earth.  Believing that the chance of duplicating
man on any other planet is the same as the chance that the planet and
its organisms have had an identical history to Earth's past, he
concludes that this duplication is highly unlikely.  Simpson's
arguments precipitated the concern whether evolution on earth is
typical of life elsewhere or simply an anomaly unlikely to repeat
itself.  I again disagree with Simpson's reasoning and instead feel if
life does form in our universe, intelligence will eventually emerge.
I do not believe that the path of our evolutionary history is the only
possible course leading to the emergence of intelligence, and instead
I feel different routes on other planets may lead to the same end
result: intelligence.

Conclusion:

Is the human race, at the brink of a new millennium, any closer to
understanding the evolution of human intelligence than our ancestors
were?  As decades have passed, evolutionists, psychologists, and
researchers have planted new theories and opinions, but the highly
awaited flower, providing absolute answers and appeasing our burning
curiosity, has not blossomedE

However, although society has not reached an absolute conclusion, we
have made great strides in our search.  For example, one argument
suggests that human intelligence evolved during the late Ice Age
because early humans needed strong mental abilities to survive the
environmental fluctuations.  Moreover, the capacity for language,
considered an integral component of intelligence, emerged during the
Ice Age, and therefore these theories complement each other.
Furthermore, although various studies test different quantitative
aspects, such as brain size or DNA count, they all seem to conclude
that intelligence has directly progressed with evolution.

Another current debate revolves around the inevitability of human
intelligence, and although I agree that animals, such as chimpanzees,
have the ability to communicate and express opinions, I still believe
a distinction exists between human-level intelligence and the
intelligence used by other creatures.  However, I believe that once
life forms intelligence will inevitability surface and eventually
equal or surpass the human level.  As far as is known, intelligence is
beneficial for survival, and therefore I feel this characteristic will
eventually evolve.  I also believe that evolution is a continuous
process, always influenced by mutations and environmental
fluctuations.

Humans have recently expanded this study of intelligence from a global
to a universal frame, looking beyond our world to the vast, unknown
space surrounding earth by searching for neighbors in our galaxy.
Because I believe intelligence is inevitable, I feel that if life
exists in our universe, human-level intelligence will eventually
emerge.  However, only when we find another intelligent species in our
galaxy can humans truly learn and compare about the origin and
evolution of human intelligence.  We research, we debate, and we
attempt to define this term in quantitative approaches, but in the
end, we will need another case study-another intelligent
civilization-to draw any strong conclusions.