Transcript Lecture 9: The Beginnings of Evolutionary Psychology

The Beginnings of Evolutionary
Psychology: Darwin’s Important Idea
Dr. Paul Dockree, History of Psychology: PS1203, 2009
Heraclitus (circa 535–475 BC)
Heraclitus (pre-Socratic)
“The Weeping Philosopher”
His philosophy is recognized
as similar to Taoism
Everything flows and nothing stands still.
Panta rhei - everything flows
"one cannot step twice into the same river."
Whereas the Pythagoreans and Plato had emphasized harmony,
Heraclitus suggested that life was maintained by a tension of opposites
Wisdom comes from understanding this eternal dynamic
The big 19th Century debate:
Are species static or changing?
Many people, including respected scientists such as Harvard’s
Louis Agassiz, believed the world was created and set in motion
according to Newton’s laws, but was otherwise static.
Statute of
Agassiz at
Stanford U.
Zoology building
after San
Francisco
earthquake
Louis Agassiz, a Swiss zoologist and palaeontologist, was one of
many respected scientists of the time who believe that the natural
history of humans as a species was specified by God
Progress in the 18th & 19th centuries
•
Natural order of the world –
hierarchical structure to society .
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Momentous change after the
Renaissance period
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Idea of progress though outpacing
the competition.
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Dismissal of superstitions and
acceptance of science
•
Biological based evolutionary
progressive ideas from Erasmus
Darwin
Jean-Baptiste Lamarck (1744-1829)
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French Naturalist and early
proponent of evolution
He classified animal collections in
the Paris Museum of Natural
History
He believed that evolution occurred
because of a tendency for
organisms to become more
complex
Teleology: a doctrine that holds
there is a final cause or purpose
inherent in all beings.
E.g., we have eyes in order to see
vs modern naturalist view: a person
has sight because of his eyes
(function follows form)
Consistent with Lamarck, the tree of
human evolution
according to Ernst Haeckel, 1891
At the top of Haeckel's tree are
Menschen - men, and Haeckel
meant white European males
Haeckel's tree explicitly embeds
the notion of progress - things nearer
the top are 'more evolved' or
'higher.‘
Lamarck is remembered primarily for a
theory of "inheritance of acquired
characters" or Lamarckism
Lamarck’s idea was the inheritable changes
are brought by the internal needs and efforts of
the organism - "use and disuse" of
characteristics
Charles Robert Darwin (1809 – 1882)
• Young Cambridge
graduate in 1831 but
not inspired by his
university education
• Applies for the post
of Naturalist on the
H.M.S Beagle
captained by Robert
FitzRoy
Route of Darwin’s voyage
on the Beagle, on which he
was official ship naturalist.
He collected and sent to
London large collections of
varying species.
Darwin’s observations and ideas
• What are the possible functions of all
animal characteristics?
• Animals differed dramatically according to
their geographical distribution (i.e., their
environment)
The Theory of Evolution by Natural
Selection
• Darwin was aware that other naturalists like JeanBaptiste Lamarck has a rival theory of evolution.
• Lamarck’s theory could not explain non-voluntary
characteristics.
• However, Darwin was convinced of the idea that
evolution needed to be taken seriously in
opposition to the idea that species were created as
perfect fully-formed entities.
The Theory of Evolution by Natural
Selection
Darwin suddenly thought of a plausible
mechanism for the gradual evolution of
countless stable species in a state of
nature – inspired indirectly by Thomas
Malthus:Thomas Malthus’ Essay on the
Principle of Population as It
Affects the Future Improvement
of Society (1798) inspired
Darwin to discover
the role of natural selection in
the development of species.
The Theory of Evolution by Natural
Selection
• Darwin honed in on this idea of a natural check on
population growth
• Those who do survive will disproportionately tend
to be the ones best adapted to overcoming the
particular dangers of their own particular
environment.
• And if their adaptive characteristics are inheritable
we have a mechanism for natural selection!
The Theory of Evolution by Natural
Selection
•
Darwin provided support for his
theory with a tremendous amount
of supporting evidence from his 5years of data collection from his
voyage on H.M.S Beagle
•
The theory and evidence was
published “On the Origin of
Species by Means of Natural
Selection, or the Preservation of
Favoured Races in the Struggle for
Life” in 1859
•
Arguably the most important book
of the century.
Darwin and Psychology
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Darwin’s Descent of Man (1871)
“there are no fundamental
differences between man and
higher mammals in their mental
capacities”
• E.g., courage, kindness, jealousy,
pride, shame, playfulness,
dreaming, learning from
experience
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“The difference in mind between
man and the higher animals, great
as it is, certain is one of degree and
not of kind”
Darwin argued that human emotional
expression are inherited and evolved
characteristics, best understood as the
direct or indirect consequences of
reactions that had adaptive or survival
value
Human expressions,
some posed and some
candid, appeared in
Darwin's “Expression of
the Emotions in Man and
Animals” (1872).
If people all over the world,
no matter how isolated,
showed the same facial
expression of emotion,
those expression must be
inherited instead of learned
The English Philosopher
Herbert Spencer (1820 - 1903)
coined the phrase
“survival of the fittest”
Spencer applied evolutionary
thought to society and laissez-faire
economics and helped create the
ideology known much later as
“social Darwinism,” an ideology
which Darwin himself never
endorsed.
Darwin’s legacy
The brain and mind could
no longer be regarded as
static “givens”
The mind is a functional
entity aiding the
adaptation of the
individual to the
environment
All Darwin’s works, including images
of his original notebooks are available
online at: http://darwin-online.org.uk/