Today we will

1
Today we will

• Consider how biological psychologists might
  explain sex gender
• Examine chromosomal influences on sex/gender
  development
• Examine hormonal influences on sex/gender
  development

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2

• What do biological psychologists believe about
  the causes of experience and behaviour?
• How might a biological psychologist explain
  sex/gender differences between people?

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3
Sex chromosomes

• Genetic blueprint for a person is organised into
  23 pairs of chromosomes
• 22 pairs are both X shaped. the 23rd depends on
  whether the person is female or male
• XX female XY - male

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4
Sex chromosomes
source US National Library of Medicine
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Chromosomes hormones

• Everything develops as a female unless instructed
  otherwise
• The Y chromosome contains instructions for the
  body to produce androgens (male sex hormones)
• These cause the embryo to develop along the male
  path

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6
Sexual development
XX
Development of ovaries, uterus and vagina
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7
Sexual development
XY
Development of testes instead of ovaries
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Development of penis Changes to brain
8
Hormones

• What might be the result if
• An XY foetus was insensitive to androgens?
• An XX foetus was exposed to unusually high levels
  of testosterone?

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9
Atypical chomosomes

• Turners syndrome
• XO only one X chromosome on 23rd pair
• Klinefelters syndrome
• XXY additional X chromosome on 23rd pair

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10
Atypical chromosomes

• Would people with these syndromes (Turners,
  Klinefelters) appear male or female?
• How might they be different from those with more
  typical chromosomes?

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11
Turners syndrome
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• Photographs on next slide

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13
Turners syndrome
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Turners syndrome

• Physical differences (neck, stature)
• Underdeveloped ovaries, lack of menstruation at
  puberty
• Poor spatial and mathematical abilities
• Poor social adjustment

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15
Klinefelters syndrome
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• Photographs on next slide

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17
Klinefelters syndrome
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Klinefelters syndrome

• Physical differences (stature, limbs)
• Underdeveloped genitalia
• Gynaecomastia in some cases
• Poor language abilities, learning difficulties
• Shy and passive temperament

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