Gender

1
Gender

• Males gt Females

2
Introduction

• One of the most interesting differences appear in
  the way men and women estimate time, judge speed
  of things, carry out mental mathematical
  calculations, orient in space and visualize
  objects in three dimensions, etc. In all these
  tasks, women and men are strikingly different, as
  they are too in the way their brains process
  language.

3
Introduction

• This may account for the fact that there are many
  more male mathematicians, airplane pilots,
  engineers, architects and race car drivers than
  female ones.

4
Introduction

• On the other hand, women are better than men in
  human relations, recognizing emotional overtones
  in others and in language, emotional and artistic
  expressiveness, esthetic appreciation, verbal
  language and carrying out detailed and
  pre-planned tasks

5
Brain Mass

• Male brain is, however, 10 larger than females
• Males have larger bodies, more muscle, and thus
  need more neurons to control them
• However, while men have more neurons in the
  cerebral cortex, women have a more developed
  neuropil, which is the space between cell bodies,
  which contains synapses, dendrites and axons, and
  allows for communication among neurons

6
Neurons

• This may explain why women are more prone to
  dementia than  men
• Although both may lose the same number of neurons
  due to the disease, males would be less affected
  since they have a larger number of nerve cells,
• This could prevent some of the functional losses

7
Speech

• Two areas in the frontal and temporal lobes
  related to language (Broca and Wernicke) were
  significantly larger in women
• This provides a biological reason for women's
  superiority in thoughts associated with language
• Using MRIs, scientists found that women had 23
  more volume in Brocas area and 13 more volume
  in Wernickes area than men did

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Speech cont.

• The female brain processes verbal language
  simultaneously in the two hemispheres of the
  frontal brain
• Men tend to process it in the left side only.
• This difference was demonstrated in a test that
  asked subjects to read a list of nonsense words
  and determine if they rhyme
• People who use pictographic written languages
  tend also to use both sides of the brain,
  regardless of gender.

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Inferior-Parietal Lobule

• Scientists working at Johns Hopkins University
  have discovered that there is a region in the
  cortex, called inferior-parietal lobule (IPL)
  which is significantly larger in men than in
  women
• This area is bilateral and is located just above
  the level of the ears

10
IPL continued

• Furthermore, the left side of the IPL is larger
  in men than the right side
• In women, its the other way around
• Although the difference between left and right
  sides is not so large as in men, noted the JHU
  researchers
• This is the same area which was shown to be
  larger in the brain of Albert Einstein, as well
  as in other physicists and mathematicians.
• It seems that the IPL's size correlates highly
  with mental mathematical abilities.

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IPL continued

• The IPL allows the brain to process information
  from senses and help in selective attention and
  perception (for example, women are more able to
  focus on specific stimuli, such as a baby crying
  in the night).
• Studies have linked the right IPL with the memory
  involved in understanding and manipulating
  spatial relationships and the ability to sense
  relationships between body parts.
• It is also related to the perception of our own
  affects or feelings. The left IPL is involved
  with perception of time and speed, and the
  ability of mentally rotate 3-D figures

12
Orbitofrontal-to-amygdala ratio

• One study measured the size of the orbitofrontal
  cortex, a region involved in regulating emotions,
  and compared it with the size of the amygdala,
  which functions to produce emotional reactions.
• The investigators found that women possess a
  significantly larger orbitofrontal-to-amygdala
  ratio (OAR) than men do.
• This can mean that women might be more capable of
  controlling their emotional reactions.

13
Limbic Size

• Females have a larger deep limbic system than
  males. This gives females several advantages and
  disadvantages.
• Due to the larger deep limbic brain women are
  more in touch with their feelings, they are
  generally better able to express their feelings
  than men.
• They have an increased ability to bond and be
  connected to others .
• Females have a more acute sense of smell, which
  is likely to have developed from an evolutionary
  need for the mother to recognize her young.

14
Limbic Size

• Having a larger deep limbic system leaves a
  female more susceptible to depression, especially
  at times of significant hormonal changes such as
  the onset of puberty
• Women attempt suicide three times more than men
  do
• Yet, men kill themselves three times more than
  women, in part, because they use more violent
  means of killing themselves (women tend to use
  overdoses with pills while men tend to either
  shoot or hang themselves) and men are generally
  less connected to others than are women.
• Disconnection from others increases the risk of
  completed suicides.

15
Brain Structure

• Females have a larger and more developed corpus
  callosum than men
• Better communication between the two sides
• Men tend to be more left brained
• Females have a larger and more developed frontal
  lobe than men
• Heightened perception of emotions than men
• The volume of a specific nucleus in the
  hypothalamus is twice as large in heterosexual
  men than in women and homosexual men
• This causes a debate on whether there is a
  biological basis for homosexuality

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Brain Structure

• Females have mechanisms that enable them to
  detect men that will benefit their offspring
• Genetic traits, paternal involvement
• Males can detect females that promise rapid
  production of offspring and a disinclination to
  mate with other men (healthy, faithful, and
  fertile)
• Men expect women to be faithful and women seek
  faithful men
• Men do not feel compelled to remain faithful

17
Hormones

• A hormone is a chemical substance produced by an
  endocrine gland that has a specific effect on the
  activities of other organs in the body
• The major female and male hormones can be
  classified as estrogens or androgens.
• These are present in both males and females
• Men produce 6-8 mg of the male hormone
  testosterone (an androgen) per day, compared to
  most women who produce 0.5 mg daily.
• Female hormones, estrogens, are also present in
  both sexes, but in larger amounts for women.

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Men

• In men, estrogens have no known function. An
  unusually high level, however, may reduce sexual
  appetite, cause erectile difficulties, produce
  some breast enlargement, and result in the loss
  of body hair in some men.
• Androgens are sex hormones produced primarily by
  a male's testes, but are also produced in small
  amounts by the female's ovaries and the adrenal
  gland, an organ found in both sexes.
• Androgens help trigger the development of the
  testes and penis in the male fetus. They jump
  start the process of puberty and influence the
  development of facial and body hair, deepening of
  the voice, and muscle development

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• After puberty, androgens, specifically
  testosterone, play a role in the regulation of
  the sex drive.
• Large deficiencies of testosterone may cause a
  drop in sexual desire, and excessive testosterone
  may heighten sexual interest in both sexes