The theory of Evolution

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The theory of Evolution

• Darwin and psychology

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Today

• Rationalism en empiricism
• Role in biology
• Idea of evolution
• Darwin
• Implications for psychology

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Back to scientific revolution
Opposing Cognitive styles

• Embryology

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Embryology

• Science of development
• How does the growing embryo get its ever more
  intricate structure and functions?
• Two theories
• Preformation en Epigenesis
• Each different role of egg and sperm

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Epigenesis

• Embryo starts as homogeneous blob of cells
• Differentiation
• Life force and environment
• Integration en differentiation
• Growing number of cells facilitates division of
  functions
• Omne ex ovo
• Everything flows from the egg
• Sperm just trigger

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Preformation

• Organism already completely formed at conception
• Growth of parts
• Homunculus
• Microscope
• Jan Swammerdam
• Drawings of sperm
• Trust your senses?
• All is in the sperm
• Egg only nutriment

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Theology and biology

• Protestantism
• Under an all knowing God our fate has already
  been determined
• No free will
• Predestination
• Original sin
• End of times

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Link with other issues

• Epigenesis
• Empiricism and materialism
• Spontaneous generation of life
• Preformation
• Rationalism and spiritualism
• Religion
• God is the creator of life
• Pre-wired organisms
• Who taught the spider to weave a web?
• Who taught a bird how to fly to Africa

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Continues into the 19th century

• Pasteur All life comes from other life. Life
  cannot come from lifeless matter
• Discovery of yeast
• Interconnectedness of ideas
• Pasteur was catholic
• opposed materialism
• In the present!!
• Some believe life has been planted here from
  outer space

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The idea of evolution

• Problem
• Design-argument
• How did all of nature with its intricate
  mechanisms come into existence
• Presupposes a designer
• The creator
• Common example the eye

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First theory

• Lamarck
• Evolution as transformation of species
• From simple beginnings to complexity
• Life force and environment
• Life has an inner urge to develop into ever
  higher forms
• teleology

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Differentiation of species

• Environment channels inherent development into
  different forms
• Inheritance of acquired characteristics
• Use increases characteristic which becomes
  inheritable
• Higher animals will
• Belief in progress
• Initially theory not popular
• Lamarck became popular after Darwin
• Herbert Spencer social evolution
• Uses Lamarckian mechanisms

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Necessary for evolution

• Change in cognitive climate
• An endless duration of time
• Founder
• Charles Darwin
• Icon of the 19th century

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Charles Darwin

• Most influential biologist of all time
• Including psychologist
• Gentleman scientist
• England 19th cent. Few careers for scientists
• Independent researcher
• Landed gentry/ upper class
• Peculiar person

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Marriage

• Emma Wedgwood
• Famous porcelain factory

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Marry or not marry
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Origins of Darwins theory?

• Journey of the Beagle
• Geology
• Great Chain of being
• Political theory

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a. 1831 Journey of the Beagle

• Source of inspiration for theory of evolution
• Diversity and unity of life

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Diversity
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b. Geology

• Catastrophism
• Geological catastrophes important in history of
  the earth
• Opposition to this
• Charles Lyell Uniformitarism
• Use only processes that are at work today in
  geology
• Necessary very old earth, lots of time
• Also Darwins theory

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c. Great Chain of being

• Nature does not make jumps
• Important idea in biology
• Theological background
• God is perfect and hence has created all that is
  possible
• Idea of Continuity

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d. Political theory

• 1838
• Darwin reads Malthus, An Essay on Population
• Population always increase faster than production
  of food
• Waste in nature
• More organisms are born than can survive
• If those that survive differ from those that
  die........
• Natural selection

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1859 Origin of Species

• Theory
• 1. Organisms differ in functional characteristics
• 2. Competition for scarce resources (food and
  sex)
• 3. If certain characteristics are inherited and
  if these characteristics lead to more offspring
  surviving, then these characteristics will
  increase in the population
• Defines Natural selection

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Darwins hesitation

• Chaplain of the devil
• It is like confessing to a murder
• Theory received with much enthusiasm
• However
• after 1859 much criticism
• Theory of Darwin always contested and facing
  difficulties

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Problems for Darwin

• 1. Small variations are wiped out by normal
  majority (regression towards the mean)
• 2. Originally a variation will not profit an
  organism
• Beginning wing
• Impossible to fly with, and impossible to use as
  a leg
• 3. Geological time Kelvin and the age of the
  earth
• 4. If evolution is gradual, then why gaps in
  fossil record?
• 5. Sequence of fossils gives an impression of
  progress

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Lamarckian injection solves problems

• Most important saving mechanism
• Inheritance of acquired characteristics
• 1 Swamping problem will and inheritance of
  acquired characteristics
• 2. Initial variations useless Increase in speed
  through inheritance of acquired characteristics
• 3. Kelvin Evolution needs less time
• 4. Fossil gap remains
• 5. Direction in Evolution Lamarckian solution

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Other problems of Darwin

• The ant and the peacock
• Social behavior and especially altruism
• Why does it occur?
• Problem not solved till the 1960ies
• Kin selection
• Peacock why do animals lower their fitness by
  having big ornaments?

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Sexual selection

• Descent of Man
• Sex and producing offspring central for Darwin
• So important that he developed a
• New from of selection
• Sexual selection
• Birds of paradise

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Birds of paradise

• The only difference that really counts in the
  world

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Today Darwin still contested

• Example
• Stephen Gould, popular biologist
• Left wing political preferences
• Darwin is not enough
• We need more than natural selection alone

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Implications for Psychology
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1. Reductionism and brain research

• Continuity in nature
• New brain structures evolved gradually from older
  ones
• Our faculties already present in some animals
• Reflex arc
• Reflexology
• Pavlov en Bechterev

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2. Animal behavior

• Continuity
• Our mental life already present in animals
• George Romanes
• Anthropomorphizing
• Interpret animal behavior from our point of view

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Path to more objective approach

• Anthropomorphic interpretation
• Gradually erased from research practice
• Path to behaviorism

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Behaviorism

• Object of psychology not consciousness
• But observable behavior
• Again continuity
• No mental processes in animals leads to
• no mental processes in man
• Observable behavior defines all of psychology
• John Watson

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3. Biogenetic law

• Essential idea with profound influence on
  psychology
• Important protagonist German biologist Ernst
  Heackel
• Idea stems from Embryology
• Ontogenesis Development of the individual
• Phylogenesis Development of species/ group of
  species

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Biogenetic Law

• Ontogenesis repeats phylogenis
• The development of the individual is a highly
  accelerated repetition of the development of the
  species
• Individual development is caused by the
  development of the species

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History as cause

• Individual starts off as single cell hence life
  also started unicellular
• Young embryo has characteristics of a sponge, so
  life passed through sponge like phase
• Individual passes through phase with gills, hence
  so did life
• Important
• By study of embryo one can study evolution as a
  whole
• Biogenetic law avoids problem of gaps in the
  fossil record

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Biogenetic law and psychology

• Biogenetic law often used in psychology
• The individual repeats the history of human
  nature or culture
• Examples
• Darwin
• George Stanley Hall
• Study of sexuality

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Darwin in the Zoo

• Child afraid for big animals
• Back to ape-man for an explanation
• Fear of ancestors for big animals has been
  inherited
• Fear now part of our genetic substance
• Again Lamarck inheritance of acquired
  characteristics

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Hall Developmental psychology

• Development of child follows development of human
  history
• Infancy animal period
• Child Beginning of social relations
• Play
• Adolescence Tribal relations
• Practical use
• Youth clubs to channel deviant behavior

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Biogenetic law and childhood

• Discovery of the child as a separate category
• Stage theory
• Development/ growth vs Education as active
  management
• Freedom Regulation
• Back to earlier notions
• Rationalism Empiricism
• For the Dutch
• Jan Ligthart Borderwijk

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Another field Sexology

• In 19th century ever more interest in sexuality
• History of sexual behavior
• Sexuality in children
• Austrian sexologist Lindner
• Biogenetic law
• Sucking and sexual lust
• Influences Freud and psychoanalysis
• For another lecture

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In conclusion

• Theory of evolution
• Had a large influence on psychology
• At the same time fiercely contested and
  criticized
• Redefines mans place in nature
• Dark theory
• Base processes rule our behavior
• Theory of evolution does not paint a pretty
  picture of man and nature
• Lack of meaning
• Even today many feel uneasy with emptiness of
  theory of evolution