Hormones raging in immature minds

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Hormones raging in immature minds how the
mismatch between biology and society Contributes
to the problems of adolescence
Prof Peter Gluckman FRS Wellington Dec 2006
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• We have two histories
• an evolutionary history
• a developmental history
• Mismatch arises when those histories do not leave
  us well matched to the world we live in
• And our world has changed!

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• Humans evolved with features adapted to maximise
  their fitness in the environments in which we
  evolved.
• Humans did not evolve for longevity or health
• Humans have had increasing impact on their
  environment, particularly since the upper
  neolithic, the development of agriculture,
  settlement, technology etc etc

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(No Transcript)
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• Humans are now increasingly likely to be
  mismatched to the environments they evolved to
  live in
• Social
• Communicative
• Nutritional
• Energetic
• We evolved to live in one world we live in
  another
• Obesity
• Myopia
• ? The post-menopausal phase of life
• The problems of old age
• PUBERTY

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70
France
50
Longevity (years)
?
30
1750 1800 1850 1900 1950 2000
Neo
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Evolutionary novelty - adolescence

• Adolescence is a novel phase of life
• It does not really exist in hunter-gatherer
  societies
• It did not really exist in 18th century Europe
• It is a 20th century development

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The mismatch of modern puberty

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Puberty is not a point in time

• Breast budding 7-12 years
• Pubic hair development starts soon after
• Growth spurt peaks 1 year after breast bud
• Menarche (first period) 2 years after breast bud
  (9-14 years), breast development and growth spurt
  almost over
• Reproductive competence 1-2 years later (10-16
  years)
• Maximal pelvic size 4 years after menarche (13
  18 years)

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• But the timing of puberty is changing

Redrawn from data in Ljung et al (1974) and de
Muinich Keizer Mul (2001)
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• The age of menarche fallen
• Is this evidence of pathology
• or a sign of health ?

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• Why has the age of menarche fallen ?
• Is this evidence of pathology or a sign of health
  ?

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OSLO, NORWAY
16 15 14 13
MEAN MENARCHEAL AGE (YEARS)
1800 1850 1900 1950
Ellison 1981, Hum Biol
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Menarche in the European female
20y
AGE
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Social Complexity, Nutritional overload
Indust revol Social improvement
Agriculture Settlement
20,000ya 2000ya 200ya present