Encyclopedia of Evolution.pdf - Online Reading Center

intelligence, evolution of
hunting, for defense, and for the dynamics of dominance
in groups; it enters the realm of art. Practically every language
in the world, in its primitive state, is immensely and
even wastefully complex.
• The human ability to create and appreciate art, music, and
storytelling far exceeds what can be explained by natural
selection for obtaining resources, is far more complex
and costly than would be necessary to benefit one’s family
(through inclusive fitness), and is more complex than
would result in a payback through reciprocal altruism (see
altruism).
Miller claims instead that human intelligence evolved
primarily by sexual selection. In sexual selection, the
characteristics that prevail are those that induce one sex to
choose certain individuals of the other sex. Usually, females
choose among males on the basis of visible characteristics;
sexual selection therefore favors those characteristics that the
females like the most. This is why sexually selected characteristics
reach their highest development in males in most animal
species. These characteristics may have nothing at all to do
with survival and may be entirely arbitrary. Because of this,
sexual selection has taken a different direction in every species
and has resulted in a prodigious variety of ornamentations
in male animals, such as colorful feathers in male birds,
as well as a prodigious variety of behaviors, such as courtship
dances. Females use these visible characteristics to choose
males because the genes of the males, which would be the
most important thing for them to know about, are invisible.
These characteristics therefore function as fitness indicators,
that is, they provide a visible indication of a male’s invisible
genetic quality. In order to work, these indicators must reliably
reflect the genetic quality of the male. For this reason,
fitness indicators are nearly always very costly and usually
wasteful. Only healthy male birds, with good metabolism and
free from disease, can afford to produce costly and colorful
feathers and dance and sing for hours and days on end.
It is generally the males that compete for access to
females under conditions in which males can mate with many
females. However, there is also some competition among
females to choose the males with the highest fitness. Therefore
sexual selection can cause the evolution of sexual characteristics
in both males and females. While in most animal
species sexual selection proceeds by female choice, in humans
it proceeds mostly by mutual choice. Sexual selection has
been responsible for a great number of characteristics in both
men and women.
Miller attributes to sexual selection the major role in the
evolution of all aspects of human intelligence. The mind, he
says, is not a computer to solve problems, nor is it a Swiss
army knife full of tools to help survival in different circumstances;
it is a sexually selected entertainment system. Virtually
every aspect of intelligence can serve as a fitness indicator.
A person’s abilities to create beautiful art, produce fine literature,
tell clever jokes, accomplish feats of sport, communicate
with the gods, or explain natural phenomena are indicators
of intelligence and coordination and show that his or her
genes are good—almost half of the genes are involved in the
development of the brain—and that he or she is healthy. As
mentioned above, in most species sexual selection favors male
fitness indicators and female choice. But the ability of males
to perform the acts of creativity and intelligence, and the ability
of females to understand and judge them, are so closely
intertwined that sexual selection has produced males and
females of equal intelligence and with equal abilities to create
art. Throughout history and in most cultures, it is usually the
males who have “shown off” through creativity and sports,
but females must have equal abilities in these areas or else the
strategy would not work. Since courtship activity in many
animal species represents a balance between male deception
and female ability to see through the deception, natural selection
favored females smart enough to recognize when males
are faking. Although men are, on the average, stronger than
women, due to sexual selection, the difference is less than that
observed between males and females in many primate species
(such as gorillas), perhaps because of the overwhelming
importance that intelligence—the equal intelligence of men
and women—has played in human evolution. The primacy
of artistic expression over practical work in the evolution of
human intelligence may be illustrated by what is considered
to be the most practical product of early human intelligence:
tools. Most hand axes were used as tools (see technology),
but some have been found that were much larger, more symmetrical,
and more detailed in their production than was necessary—and
which were never used. They may have been art.
The evolution of morality and kindness would have been
more than a fitness indicator for sexual selection. A female
who observed that a male was friendly and reliable—not
just to his family, and not just to those who were likely to
return the favor—would be able to conclude that he was
very resourceful, particularly if the man, at great expense to
himself, did great deeds of kindness and charity to the community
as a whole. The female would conclude not just that
he was resourceful but also that he was likely to be kind to
her as well. This would have been important especially if the
woman had a child from a previous relationship, as is frequently
the case in tribal cultures. A stepchild has no genetic
relatedness to the new father; but the mother, in choosing a
new mate, would want a man who would be kind even to a
child who was not his. Morality and kindness, as components
of intelligence, may have evolved by means of indirect reciprocity
(see altruism). In this way, Miller concludes, such
good moral qualities as kindness, reliability, and generosity
could have evolved from sexual selection. As Miller points
out, not only was Ebenezer Scrooge (the main character in
Charles Dickens’s A Christmas Carol) mean to his nephew
and a perfect example of the lack of reciprocal altruism to his
fellow citizens, but also it was no wonder that he was single.
One alternative explanation is that males and females
chose one another on the basis of youth (therefore length of
remaining reproductive life), thereby favoring the evolution
of neoteny. Larger brain size, therefore intelligence, may have
been a side effect of the evolution of neoteny, according to
this view, thereby making intelligence an exaptation rather
than an adaptation.