> ..
The hunter/gatherer theory has not been touched by the other macho man
the hunter theory. You see you need to learn to seperate those two
theories. It is rather obvious that men hunted and women gathered but
this exagerated man the hunter stereotype you talk of, I agree with.
Some use it as a straw man to bash upon the tribal male female reality
40,000 years ago;
http://en.wikipedia.org/wiki/Hunting_and_gathering
Here are just a few evidences for the differences. But E.O. Wilson also
claims that our species has been moving, mutationg, towards more
equality. This when we compare the sixe difference between male and
female of different species and the dynamics of polygamy;
Anatomy bears the imprint of the sexual division of labor. Men are on
the average 20 to 30 percent heavier than women. Pound for pound, they
are stronger and quicker in most categories of sport. The proportion of
their limbs, their skeletal torsion, and the density of their muscles
are particularly suited for running and throwing, the archaic
specialties of the ancestral hunter-gatherer males. The world track
records reflect the disparity. Male champions are always between 5 and
20 percent faster than women champions: in 1974 the difference was 8
percent in the i oo meters, 11 percent in the 400 meters, 15 percent in
the mile, 10 percent in the 10,000 meters, and so on through every
distance. Even in the marathon, where size and brute strength count
least, the difference was 13 percent. Women marathoners have comparable
endurance, but men are faster - their champions run twenty-six
five-minute miles one after another. The gap cannot be attributed to a
lack of incentive and training. The great women runners of East Germany
and the Soviet Union are the products of nationwide recruitment and
scientifically planned training programs. Yet their champions, who
consistently set Olympic and world records, could not place in an
average men's regional track meet. The overlap in performances between
all men and women is of course great; the best women athletes are
better than most male athletes, and women's track and field is an
exciting competitive world of its own. But there is a substantial
difference between average and best performances. The leading woman
marathon runner in the United States in 1975, for example, would have
ranked 752d in the national men's listing. Size is not the determinant.
The smaller male runners, at 125 to 130 pounds, perform as well
relative to women as do their taller and heavier competitors.
It is of equal importance that women match or surpass men in a few
other sports, and these are among the ones furthest removed from the
primitive techniques of hunting and aggression: long-distance swimming,
the more acrobatic events of gymnastics, precision (but not distance)
archery, and small-bore rifle shooting. As sports and sport-like
activities evolve into more sophisticated channels dependent on skill
and agility, the overall achievements of men and women can be expected
to converge more closely.
On Human Nature - Edward O. Wilson 1978
http://www.amazon.com/exec/obidos/ASIN/067463442X/qid=1036537594/
The average temperamental differences between the human sexes are also
consistent with the generalities of mammalian biology. Women as a group
are less assertive and physically aggressive. The magnitude of the
distinction depends on the culture. It ranges from a tenuous, merely
statistical difference in egalitarian settings to the virtual
enslavement of women in some extreme polygynous societies. But the
variation in degree is not nearly so important as the fact that women
differ consistently in this qualitative manner regardless of the
degree. The fundamental average difference in personality traits is
seldom if ever transposed.
The physical and temperamental differences between men and women have
been amplified by culture into universal male dominance. History
records not a single society in which women have controlled the
political and economic lives of men. Even when queens and empresses
ruled, their intermediaries remained primarily male. At the present
writing not a single country has a woman as head of state, although
Golda Meir of Israel and Indira Gandhi of India were, until recently,
assertive, charismatic leaders of their countries. In about 7 5 percent
of societies studied by anthropologists, the bride is expected to move
from the location of her own family to that of her husband, while only
10 percent require the reverse exchange. Lineage is reckoned
exclusively through the male line at least five times more frequently
than it is through the female line. Men have traditionally assumed the
positions of chieftains, shamans, judges, and warriors. Their modern
technocratic counterparts rule the industrial states and head the
corporations and churches.
These differences are a simple matter of record - but what is their
significance for the future? How easily can they be altered?...
...So at birth the twig is already bent a little bit - what are we to
make of that? It suggests that the universal existence of sexual
division of labor is not entirely an accident of cultural evolution.
But it also supports the conventional view that the enormous variation
among societies in the degree of that division is due to cultural
evolution. Demonstrating a slight biological component delineates the
options that future societies may consciously select. Here the second
dilemma of human nature presents itself. In full recognition of the
struggle for women's rights that is now spreading throughout the world,
each society must make one or the other of the three following choices:
Condition its members so as to exaggerate sexual differences in
behavior. This is the pattern in almost all cultures. It results more
often than not in domination of women by men and exclusion of women
from many professions and activities. But this need not be the case. In
theory at least, a carefully designed society with strong sexual
divisions could be richer in spirit, more diversified, and even more
productive than a unisex society. Such a society might safeguard human
rights even while channeling men and women into different occupations.
Still, some amount of social injustice would be inevitable, and it
could easily expand to disastrous proportions.
Train its members so as to eliminate all sexual differences in
behavior. By the use of quotas and sex-biased education it should be
possible to create a society in which men and women as groups share
equally in all professions, cultural activities, and even, to take the
absurd extreme, athletic competition. Although the early
predispositions that characterize sex would have to be blunted, the
biological differences are not so large as to make the undertaking
impossible. Such control would offer the great advantage of eliminating
even the hint of group prejudice (in addition to individual prejudice)
based on sex. It could result in a much more harmonious and productive
society. Yet the amount of regulation required would certainly place
some personal freedoms in jeopardy, and at least a few individuals
would not be allowed to reach their full potential.
Provide equal opportunities and access but take no further action. To
make no choice at all is of course the third choice open to all
cultures. Laissez-faire on first thought might seem to be the course
most congenial to personal liberty and development, but this is not
necessarily true. Even with identical education for men and women and
equal access to all professions, men are likely to maintain
disproportionate representation in political life, business, and
science. Many would fail to participate fully in the equally important,
formative aspects of child rearing. The result might be legitimately
viewed as restrictive on the complete emotional development of
individuals. Just such a divergence and restriction has occurred in the
Israeli kibbutzim, which represent one of the most powerful experiments
in egalitarianism conducted in modern times.
On Human Nature - Edward O. Wilson 1978
http://www.amazon.com/exec/obidos/ASIN/067463442X/qid=1036537594/
SEX DIFFERENCES IN THE BRAIN
Sex differences in the brain programmed men and women to behave in ways
that contributed to survival and reproduction in the evolutionary past.
Men have skills that would have helped them to be effective hunters,
for example, and women have superior manual dexterity, which would have
helped them to be effective gatherers. Yet it is important to realize
that behavioral differences based on sex are not entirely built into
the brain at birth for human beings any more than they are for
ringdoves. Sex-typed behavior is affected by experience as well as by
biological sex. Many psychologists refer to such experiential effects
on sex-typed behavior as "gender" but the term is often used
misleadingly because of the assumption that what we learn is distinct
from our biology. In reality, all learning is associated with changes
in brain biology, and what we are capable of learning and motivated to
learn is affected by the evolution of the brain.
The relationship between brain and behavior is a two-way street. The
brain controls behavior, but behavior may also change the brain. For
example, experience in playing sports could develop three-dimen-sional
abilities and thereby help children to excel in some branches of
mathematics, such as geometry. There is even evidence that girls who
have more experience in team sports have superior mathematical
abilities. We do not know, however, whether there is a cause-and-effect
relationship here. It might be that young women with exceptionally good
spatial abilities would be drawn to playing sports like basketball,
baseball, and soccer. Yet, there is no evidence that men who are
unusually good at sports are also good at mathematics.
Nature and nurture are often not the antagonistic forces that
psychologists of the past believed. People often gravitate toward doing
things that they are good at and thereby develop those talents.
Recent findings in behavioral neuroscience and in psychology clearly
demonstrate that the brains of men and women process information
differently. These phenomena are often controversial, but we can no
longer dismiss them as a reflection of sex-role preconceptions of
scientists. Consider the following:
o The left cerebral cortex, which houses language, is thicker in women
while the right cerebral cortex, housing spatial ability, is thicker in
men.
o Women recover language function better after left-hemisphere damage
than men do.
o Men have faster simple reaction times than women; for example, they
are faster to push a single button after a light flashes. The
differences in reaction time are statistically reliable and range from
about 10 to 20 percent, depending on the specific test procedure.
However, in tasks involving recognition of complex patterns, women are
faster.
o Men are much better than women at mental rotation tasks, such as
imagining what an object looks like from above when it is shown only
from the front.
o When quizzed about the location of objects in an office in which they
had waited, women scored up to 70 percent better than men. In such a
test of "incidental" memory, participants do not even know that they
will be tested, and believe they are just waiting for the experiment to
begin. According to Irwin Silverman and Marion Eals at York University
in Ontario, this difference may represent an inherited adaptation of
women to finding food by foraging. For example, if they remember the
exact location of different types of fruit trees and the location of
ripe fruits on the tree, they will be more efficient at harvesting them
when needed.
o Men are more likely to be left-handed, reflecting greater dominance
of the right side of the masculine brain; this could be due to greater
exposure of the male fetal brain to testosterone. Three-dimensional
spatial abilities are also localized in the right side of the brain.
o PET scans (position emission tomography) are a method of imaging
energy use in the brain. Brain cells that are more active in processing
information use more sugar as energy. PET scans can thus be used to
determine which part of the brain is active during a particular mental
activity. When asked to spell a word, men use the left hemisphere.
Women use both sides of the brain.
o Consistent with greater use of different areas of the brain for a
given task, women have thicker connections between the left and right
sides of the brain (although this finding has been controversial in the
past due to inaccuracies of measurement).
o Women feel sadness and some other emotions more keenly than men. For
example, they suffer from depression about twice as often as men.
Recent studies suggest that this differ- ence is linked to more
activity in structures of the brain collec- tively known as the limbic
system, which regulates emotions.
o Women have better skills in nonverbal communication. They send more
signals. They are better at reading the emotional content of a
photograph or the emotion conveyed by tone of voice in experiments
where the meaning of speech is garbled. They are also better at
detecting deception through body language cues.
o Homosexual men have a smaller clump of cells (known as INAH3) in the
hypothalamus than heterosexual men. The structure is closer in size to
that of women. This suggests, but does not establish, that sexual
orientation is a module determined by early brain development. If so,
then the tendency of heterosexual women to be sexually attracted to men
and the tendency of heterosexual men to be attracted to women may be
attributable to anatomical sex differences in the brain that are
present at birth.
Much of the foregoing evidence shows that brain differences are
relevant to sex roles. For example, women's nurturant roles as
caregivers and socializers of children are favored by communicative
skills and emotional sensitivity. Men's lower emotionality and better
three-dimensional skills may favor hunting, aggressive competition with
peers, and warfare.
To say that these differences exist is not to say that they cannot be
changed or that they apply to the same extent for everyone. For
example, there is a sex difference in spatial ability of rats and other
rodents mirroring humans' spatial abilities. In rats, the sex
difference is based on fewer neural inputs to the hippocampus (a
structure of the brain) for females. Janice Juraska of the University
of Illinois at Urbana-Champaign has found that when female rats receive
toys to manipulate, the innervation (nerve input) of the hippocampus
increases. A parallel human finding-just noted-is the recent discovery
that girls who are active in team sports do better at math. According
to this view, declining sex differences in math may represent changing
lifestyles for young women.
Much of the controversy about the biological basis of brain dif-
ferences stems from thinking about the brain as though it were a
computer. Some aspects of the computer model are appropriate. For
example, it appears that sexual orientation for men is fixed early in
life and changes little. In that sense, it might be appropriate to
think of sexual orientation as analogous to a microchip that is etched
in early development as a result of the brain's exposure to sex
hormones. Many aspects of brain function, however, are constantly being
modified by environmental experiences from outside and by hormonal
influences from inside. Some of the more dramatic examples of adult
brain plasticity include the following:
o When children learn to play stringed instruments, the area of the
brain cortex "answering" to the fingers of the left hand gets larger,
according to the work of Ed Taub and others at the University of
Alabama, Birmingham. The left hand is used to finger the strings
producing different notes. The right hand, which clasps the bow,
maintains a constant grip so that the fingers have less to "learn."
o The architecture and connections made by individual cells in the
brain are constantly changing. This allows for some recovery of
function in stroke victims.
o Hormones produce constant change in neurons. For example, Estrogen
promotes sprouting of new connections (dendrites). In addition, men do
better on mental rotation tasks in the spring, when testosterone levels
are lower, than in the fall, when they are higher; this seems perverse
when you consider that male superiority in mentally rotating objects is
due to the early influence of testosterone on the fetal brain.
o Men are much more likely to commit crimes of violence at ages when
their testosterone level is highest (late teens to early twenties);
this shows that the hormone primes the human brain for aggression.
o Testosterone level is also a primary determinant of sex drive in both
sexes. As men age, their testosterone level declines and sex drive is
somewhat reduced. As women approach middle age, their testosterone
level rises relative to estrogen and libido tends to increase. The
generally higher level of sexual behavior seen in men compared to women
is clearly relevant to their greater proclivity for casual sex, but it
might not be entirely due to different levels of testosterone in the
blood. Other plausible alternatives include sex differences in brain
anatomy and brain chemistry, parental inculcation of personal modesty
in girls, and anatomy and physiology of the genitals.
ADAPTIVE SEX DIFFERENCES IN THE BRAIN
Just as women excel at remembering the location of objects, a skill
that is directly relevant to foraging, men have better motor skillsat
least those that are used for hunting. In all hunter-gatherer societies
studied by anthropologists, men do most of the hunting of large
animals, although women are often involved in collecting or trapping
small animals, in fishing, and in driving game animals into traps. It
is very unusual for women to be involved in killing large game animals
by throwing projectiles at them such as spears or rocks, or striking
them with precisely targeted weapons such as arrows from a bow or
poisoned darts from a blowgun.
Natural selection is the name of the process through which species
acquire the bodily and behavioral characteristics that help them to
survive and reproduce. Naturalists have always been impressed by the
astonishing congruence between the bodily design of animals and the way
this design enables them to live. The hummingbird's beak is exactly the
right shape and length to reach the nectar at the base of a deep flower
on which it feeds. The astonishingly long necks of giraffes similarly
explain what separated the successful giraffe from less successful
members of the species in reaching the leaves of tall trees. The key
point about natural selection is that it is a means by which unsuitable
types get weeded out. Giraffes with unusually short necks are not
successful at getting enough to eat and are less successful at
surviving and reproducing; their genes are therefore selected out of
subsequent generations, making it unlikely that short-necked giraffes
would be born. In a similar vein, men who were inept hunters had
difficulty attracting a mate and left fewer children to perpetuate
their incompetence in bringing in game. Being a poor hunter did not
have such dire consequences for ancestral women, however.
If natural selection had acted on the brains of men to improve their
success as hunters, then men should be considerably better than women
at throwing objects precisely enought to hit a target. According to the
research of Doreen Kimura at the University of Western Ontario, London,
there is a large sex difference which favors men in tasks of precise
targeting. On a dart-throwing task, for example, the average man did
better than 84 percent of the women even though success at the task did
not require strength.
It would be hard to reduce this finding to any simple difference
between men and women in muscle function, size, or strength. The
results indicate that it was due to a genuine difference in brain
processing of visual-spatial information. One might imagine that the
difference could be explained in terms of the greater participation of
men than women in sports like baseball and basketball, where targeting
ability plays an important role. Yet, when Kimura used statistical
control of sports participation level, she found that it accounted for
only a trivial portion of the sex difference. Whatever their
participation level in sports, men performed much better than women on
tasks involving targeting.
Consistent with the argument that men have superior visual- spatial
processing capacity, Kimura found that they were also better at
blocking a Ping-Pong ball with their hands after it was flung from a
launcher, although the sex difference in this task was only half as
large as for the targeting activity. Speed of reaction might seem to
offer an advantage here, but statistical control showed that the sex
difference was not due to women having slower reaction times. Men excel
in the higher level integration of visual and motor information, which
makes sense in terms of behavioral adaptations because they would have
used such aptitudes as hunters.
What makes these findings so fascinating is that women do not have
poorer motor coordination than men. In fact, when you look at tasks
requiring fine manual dexterity, women are reliably better than men.
According to conventional tests of dexterity, this advantage is not
simply due to women's greater manual adroitness because of the smaller
size of their fingers. Kimura's research has shown that women perform
much better in tasks that require them to control fingers individually
such as bending a finger at the joint without moving any of the other
fingers.
Again, this advantage of women in fine manual dexterity is consistent
with the kind of work they perform most frequently in subsistence
societies. These activities include gathering of small fruits and nuts,
weaving baskets, making thread, and producing clothing. It is no
accident, perhaps, that men are not often drawn to needlepoint and
quilting as hobbies and are rarely seen in the local knitting circle.
It is true that they might be made to feel uncomfortable if they
cultivated such stereotypically feminine hobbies, yet this begs the
question of why such hobbies are associated with women. Presumably,
women cultivate them because they tend to be good at them, perhaps as a
side effect of their evolutionary development of foraging skills.
Despite men's average deficiency in manual dexterity compared to women,
many musicians are men. There is no question that playing a musical
instrument is a severe test of manual dexterity. Male musicians may
have unusually good manual dexterity to begin with, or they may develop
it through practice.
It has been noted that in addition to testing higher on targeting
activity men test better on mental rotation tasks than women. In mental
rotation tests, people mentally rotate some object and decide what it
would look like if viewed from another angle. Given that men evolved as
hunters who traveled farther from the home base in search of game
animals, it is possible that their superiority on spatial rotation
tasks reflects an adaptation for finding their way around the
landscape. Kimura and her colleagues tested this idea by asking
subjects to learn a route through a streetmap. The experimenter first
traced the route using a stylus that left no mark. Participants were
then asked to trace the same route from memory. When they made a
mistake, the experimenter corrected them and recorded the error. Men
learned to trace the route correctly after fewer trials, and they made
fewer errors before learning. Better scores on the map task were
correlated with better spatial rotation scores, suggesting that the
masculine advantage in some spatial aptitude tests may be due to a male
adaptation for finding prey throughout their territory. Although it is
approximately ten thousand years since most humans made their living by
hunting, this is only one half of one percent of our two-million-year
history as a species. Genetically speaking, we are virtually identical
to our hunter-gatherer ancestors.
Not only did men and women in Kimura's study learn the map task at
different rates, but after it had been mastered, they had absorbed
different kinds of information. Men acquired more knowledge about
distances and directions. Women recalled more details about landmarks
and street names, reflecting their superior memory for the location of
objects. This sex difference influences the way people give directions.
Men operate as though referring to a mental map. Typical instructions
are: "Go north three blocks, take a right on Union Avenue, go east four
blocks, take another right on First Street, you will see it on the
right half way up the block." Women's directions tend to be more
concrete, vivid, and detailed. Instead of referring to a mental map, it
is as though they were actually perceiving details on the route they
are describing. When giving directions, a woman is more likely to refer
to concrete objects along the route: "Go to the post office, turn right
(that's Union Avenue); keep going until you see McDonald's, turn right
on the wide street with trees on both sides-that's First Street. Ours
is the white house with blue trim halfway down the block."
What makes the adaptationist (i.e., evolutionary) account of sex
differences in spatial orientation so compelling is that a similar phe-
nomenon has been observed in voles, or field rodents. Among species in
which males range farther than females, they have an advantage in maze
learning, reflecting superior spatial skills, but there is no sex
difference for species having the same-sized home range. Among
laboratory rats, males perform better on mazes than females and are
more likely to rely on geometric cues, whereas females rely more on
landmarks such as scratches on the walls of the maze.
The difference in rotational ability between sexes has been observed in
all societies studied, with the interesting exception of the Inuit. The
fact that women and men do not differ in spatial ability tests might
have something to do with the exceptional visual challenge of living in
a featureless tundra landscape that is constantly changing as snow
drifts move about. Parents of both sexes must be vigilant in order for
children to survive. Young children of the Inuit differ, however,
showing that the difference is probably present at birth, reflecting
early sexual differentiation of the brain. The demands of the
environment evidently promote spatial ability of Inuit women until they
equal those of men.
The effect of changing levels of hormones in the blood on
sex-differentiated abilities is complex. When women are at the
highestrogen phase of their menstrual cycle, they perform better on
tasks like verbal fluency and fine motor control, for which there is a
feminine advantage. Men's testosterone level varies considerably over
the course of a year, with a peak in the fall and a trough in spring.
So much for springtime love and pigeons cooing. Men with generally high
testosterone levels have poor spatial abilities. Men's scores on manual
dexterity, verbal fluidity, and other femalefavoring tasks do not
change with the seasons. Taken together, these results provide
compelling evidence that early brain differences are the underlying
cause of differences in cognitive abilities between men and women.
Apparently, sex hormones can modify these differences later in life
also. These sex-related brain differences are of great interest in
their own right, but they also provide compelling evidence that the
brains of men and women have evolved differently. This helps to explain
differences in sexual behavior between the sexes. As the French say,
viva la differenced
The Science of Romance - by Nigel Barber
http://www.amazon.com/exec/obidos/tg/detail/-/1573929700/
