Transcript Sex Differences - Dr. Michael Mills

Sex Differences
 There are significant sex differences in the areas of
aggression, risk taking, self esteem, status seeking, and group
formation that can be explained by only the males need to
compete for mates, not the female's.
 Females naturally became the "default sex", meaning their
psychology was determined by the fact that they were not
masculinized.
 Female competition was kept in balance by the mother's need
to guarantee her own survival and her reproductive investment.
First Premise - Dominant Males Get The
Biggest Prizes
 The desire to mate with multiple females cause
intense male competition.
 The majority of men almost everywhere have
monogamous marriages and relationships.
 Monogamy can actually help ensure offspring
survival, especially with females.
Second Premise - Male Competition Causes
Men's Generalized Taste For Risk
 Risk taking in general is higher in males than in
females.
 Men's precarious behavior comes from their lack of
concern with their own well being, compared to that
of women.
 Female's lower risk taking resulted from a sex
difference in the magnitude of what could be gained
by aggression.
Third Premise - The Rewards Of Female
Competition Are Low
 Women's aggression is lower because they do not need to
compete with each other in order to copulate.
 Women's success depends on their capacity to provide their
offspring with food.
 Evolution has created women to survive longer than men.
 This is because whichever sex provides the most parental care
should be selected by nature for better longevity so they can
protect their offspring to maturity
Women, competition and low
risk-aggression
 Fear is what keeps females at a less lethal
level of competition than that of males.
However, females still need to compete.
 There are TWO forms of low-risk tactics that
females use.
– 1. An unwillingness to escalate to direct
combat
– 2. A preference for indirect rather than direct
forms of aggression.
Meta Analysis
 Meta analysis is a statistical technique that combines studies
to estimate the magnitude of the sex differences based on
thousand of subjects.
 Meta-analysis confirms that the sex difference is greater for
physical aggression than for verbal/psychological aggression.
 Using meta-analysis it was found that the smallest sex
difference for physical aggression was that 62 percent of men
are more aggressive than the average woman, while the
largest finds that 82 percent of men exceed the average
woman. With verbal aggression it was found that there was no
significant sex difference. It is suggested that 69 percent of
men are more aggressive than the average woman
Meta Analysis
 Using meta-analysis it was found that the smallest
sex difference for physical aggression was that 62
percent of men are more aggressive than the
average woman, while the largest finds that 82
percent of men exceed the average woman. With
verbal aggression it was found that there was no
significant sex difference. It is suggested that 69
percent of men are more aggressive than the
average woman
Eagly and Steffan
 They conducted an experiment and concluded that
women have a general tendency to experience
greater fear than men do in relation to angerprovoking situations. It was concluded that the
greater the danger and anxiety the female feels the
less likely she is to be aggressive. Men and women
faced objectively the same situation and yet males
showed less fear and more aggression.
Eagly and Steffan
 For men, provocation raised their levels of aggression and it
did so equally for verbal and physical aggression. For women,
provocation had a much greater effect on their willingness to
be verbally aggressive than on their willingness to risk physical
aggression.
 The ironic part is both men and women have anger, and it had
been recorded that both sexes are angry six times a week. The
sexes do not differ in the intensity of their anger that they feel.
Women are reluctant to express their anger as an upright
physical attack but there are other ways of competing
Types of aggression
 Indirect aggression is one way that females compete, it is a
form of social manipulation where the target is attacked
indirectly and the aggressor can therefore remain unidentified.
 Some examples of indirect aggression are shunning,
stigmatizing, and gossiping. It excludes rivals and destroys
their reputation without a head on confrontation and it is one
form of aggression in which females exceed males
Types of aggression
 Girls are more likely to exclude newcomers than are
boys. This form of aggression starts in girls as they
polish the social and verbal skills necessary for this
invisible form of victimization. By the age of eleven
girls are higher than boys on becoming friendly with
someone as a way of revenge, gossiping, and a way
to suggest shunning another. Studies of school
bullying also report that girls employ indirect
strategies of stigmatization and exclusion that often
has a devastating effect upon the victim.
Types of aggression
 This form of aggression continues into adulthood.
Investigating victimization in the workplace found
that women more than men use indirect forms of
aggression such as spreading false rumors, and not
speaking. An ethnographic study in Buenos Aires
concluded that women are extremely competitive
and envious of each other, and female competition
is expressed through comparisons regarding
clothing, and appearance.
Types of aggression
 Primate females also use indirect aggression.
Females have been observed harassing other
females for days or weeks and interrupting her when
she is trying to rest, feed, or mate. This harassment
takes its toll on the female by causing stress and
can even cause abortion. These indirect tactics
diminish the reproductive success of the victim;
therefore there are more resources for the victor and
her offspring.
Maternal aggression-a
predictable paradox
 There is one clear situation where the pay offs for aggression
by females are much larger than that of males-saving her
child's life. The life of her offspring has cost the mother much
time, and effort. The cost for the male is a few minutes of his
time and easily replaceable sperm. The cost of replacement for
the mother is measured in years while the father is measured
in minutes
Maternal aggression-a
predictable paradox
 Maternal aggression has been documented in many species,
and it occurs when another animal approaches or interferes
with one of a female’s offspring. The species in which it has
been documented are those where male infanticide is a
serious threat to female reproductive success. The mothers
attack is ferocious and immediate, in these species the
females are extremely sensitive to the presence of males near
infants and when an infant shows distress a nearby male may
be attacked even if he has displayed no aggression towards it.
Maternal aggression-a
predictable paradox
 Maternal aggression begins during pregnancy and continues
through lactation, suggesting a strong hormonal component.
The duration of maternal aggression corresponds with the
period when the young are most vulnerable. It disappears
when the pups are removed for five hours but it is restored five
minutes after the pups are returned. If the pups are attacked or
killed, maternal aggression switches off immediately.
 The severity of maternal attack is directly related to the size of
the litter that the female is protecting. In primates threats to the
infant come from other females as well as infanticidal males.
Maternal aggression-a
predictable paradox
 Females will start pulling, rough handling, kidnapping and
using direct aggression towards another females young. In
these species females display a dominance hierarchy that is
based on matrilines. High ranking females of course have little
to fear from low ranking females. This leads to a distinct
pattern of maternal protection of young that depends on the
females standing in the group. Low ranking females protect
their infants by restraining them, high ranking mothers give
their offspring greater freedom because they have less fear
from launching an attack on any low ranking female that tries
to abuse them.
Type I Theorist
 The first type are called the high-fear theorists who believe that it is
extreme levels of fear that switch on the severe form of aggression
used by mothers.
 The high-fear theorists make a distinction between two forms
of aggression. Offensive aggression is used by female rodents
principally against other females and these attacks rarely
cause severe injury. These attacks on females by females
seems to be a warning to the female intruder to get away from
the space she considers her own. These attacks involve a very
low level of fear on the part of the aggressor. However,
females show a very different response to a male intruder
because they are far more likely to have infanticidal intent than
females.
Type II Theorist
 The second type are called the low-fear theorists who believe
that it is a temporary reduction in fear that enables the mother
to attack with such ferocity
 Low-fear theorists see aggression as a straightforward
continuum from mild to severe. they believe that the more
fearful the animal is the less likely it is to launch a severe
attack. It is there fearlessness that opens the door for
aggression. It was found that mice from genetic lines that show
high levels of aggression also show lower levels of anxiety,
and a high level of anxiety is inversely related to the probability
of showing maternal aggression
Oxytocin
 Oxytocin is a neuropeptide made in the hypothalamus that
stimulates the contractions that expel the infant from the
uterus. It is responsible for the milk letdown and is triggered by
the nipple stimulation of suckling
 Oxytocin has been called the love and bonding hormone. It has
a very special affect on mothering . Psychologically, oxytocin
promotes a feeling of well being and tranquility. It enables the
growing sense of love and attachment to the infant. The more
the infant suck the more oxytocin is produced.
 In mothers it increases their attachment to their infant,
promoting the feeling of love, and makes her infant more
valuable to her. It also suppresses the fear that would normally
cause her to back off from threat.
Fear and fitness
 The difference between men and women in their willingness to
move from conflict to violence is tied to the reproductive
strategies of the two sexes
 With males physical aggression has brought rewards that
outweighed the risks. Males are more concerned with
reproducing rather than their own survival and well being,
therefore they will risk their own life for a chance to reproduce.
Physical aggression for males intimidated other males and in
doing so, won the victor status. The more successful he was
the greater freedom he had, not only to claim fertile females
but also to monopolize over disputed resources and food.
Fear and Fitness
 For females aggression has costs that males do not have to
face. For females injury or death means the loss of her current
offspring. For these reason females avoid unnecessary conflict
and stay away from physical aggression-both threaten the
huge investment that a woman had made in rearing her
dependent young.
 Anne Cambell believes that the mechanism that underlies the
sex difference of aggression is fear.For males, low levels of
fear open the door to extravagant displays of bravery and
combat that can be used to achieve a reputation in the
community. The prize is status and all the benefits that come
with it.
Interesting/Confusing Point:
-Most men have monogamous
marriages or relationships