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HS-05-Darwin1week4.pptxContemporary Issues: Historical Framework of Contemporary Psychology
Unit 5
Darwin’s Century: Evolutionary Thinking
The Species Problem
pre-Darwin: species are invariable
Genesis:
20 And God said, Let the waters bring forth abundantly the moving creature that hath life, and fowl that may fly above the earth in the open firmament of heaven.
24 And God said, Let the earth bring forth the living creature after his kind, cattle, and creeping thing, and beast of the earth after his kind: and it was so.
“Mystery of Mysteries”
How do new species originate
What accounts for the large number, the diversity, the occasional disappearance, the existence of fossils, etc.?
The Species Problem
Big problem for academics in Great Britain
‘Natural Theology’: Profs also members of the clergy
“There is for a free man no occupation more worthy and delightful than to contemplate the beauteous works of nature and honour the infinite wisdom and goodness of God.”
John Ray, parson-naturalist
William Paley (1802) the argument from design
Natural Theology or Evidences of the Existence and Attributes of the Deity.
The Watchmaker Analogy:
Elegant design requires a designer (i.e., God)
The Watchmaker Analogy
“In crossing a heath, suppose I pitched my foot against a stone, and were asked how the stone came to be there; I might possibly answer, that, for anything I knew to the contrary, it had lain there forever: nor would it perhaps be very easy to show the absurdity of this answer. But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place; I should hardly think of the answer I had before given, that for anything I knew, the watch might have always been there. ... There must have existed, at some time, and at some place or other, an artificer or artificers, who formed [the watch] for the purpose which we find it actually to answer; who comprehended its construction, and designed its use ... Every indication of contrivance, every manifestation of design, which existed in the watch, exists in the works of nature; with the difference, on the side of nature, of being greater or more, and that in a degree which exceeds all computation.”
Early Evolutionary Ideas
Jean Baptiste de Lamarck (naturalist)
Evolution by inheritance: (Theory of Use & Disuse)
physiological needs created by interactions with environment cause biological structures to enlarge or shrink
all such changes were heritable
Diff from C. Darwin but still:
1) adaptive change in lineages
2) ultimately driven by environmental change
3) over long periods of time
Erasmus Darwin: Charles Darwin's grandfather
physician, philosopher, poet, botanist, naturalist
Zoonomia, or, The Laws of Organic Life (1794)
“...that all warm-blooded animals have arisen from one living filament, which the great first cause endued with animality...and thus possessing the faculty of continuing to improve by its own inherent activity, and of delivering down those improvements by generation to its posterity, world without end?... “
Charles Darwin & Voyage of the Beagle
Charles Darwin (1809-1882)
Cambridge: Henslow (bio) & Sedgewick (geology)
Voyage of the Beagle to S. Amer (1831-36)
Galapagos Islands, 500 miles west of S. America
Newly formed volcanic island
Henslow recommended him as self-funded naturalist
Darwin was 22 and just finished his degree to become a parson
Ship’s Surgeon was ‘official’ naturalist
Emphasis on geology (zoology notes ¼ of geology notes)
Supported Lyell’s “uniformitarian” views of geology
Natural processes that operate now have always operated in the past and apply everywhere in the universe
Lyell suggested fossils found in rocks were actually evidence of animals that had lived many thousands or millions of years ago
Darwin’s Finches the ‘classic story’
Finches on Galapagos Islands
variety of finches
vary in the shape and size of their beaks
Single breed of finches colonized Galapagos & then diverged in form.
distance between the islands prevented interbreeding
distinct populations on different island
Different populations specialized for different food sources
birds with thin, sharp beaks eating insects
birds with large, sturdy beaks eating nuts
Charles Darwin’s Theory of Evolution
Huge specimen collection sent back to Cambridge
Darwin’s Finches
Collected many species of birds
Failed to note which island they came from
Reconstructed from other’s notes
In London, told that different birds were all finches that looked different from one another.
“I have strong reasons to suspect that some of the species of the sub-group Geospiza are confined to separate islands. If the different islands have their representatives of Geospiza, it may help to explain the singularly large number of the species of this sub-group in this one small archipelago, and as a probable consequence of their numbers, the perfectly graduated series in the size of their beaks. (pp403-420)”
Darwin’s Theory Evolves
An Essay on the Principle of Population, 1798 Thomas Robert Malthus.
Population grows faster than food supply
Produces a “struggle for existence”
Nature selects from variants to create perfect structure
Selective Breeding (artificial selection)
Sought out info from plant & animal cross-breeders
Focused on pigeon breeding
All domestic pigeons likely descended from rock pigeon
Artificial selection implies an analogy to nature
i.e., “natural selection”
On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life
Charles Darwin
24 November 1859
http://darwin-online.org.uk/contents.html#origin
The Delay
could have published theory of evolution in early 1840s
Had been working on since late 1830
Health (his & family)
Concern about Vestiges of Creation (1844)
a quasi-scientific book supporting evolution
Rejected by scientific community
Scientific Conservatism
Working-class reform movement
Most scientists were upper-class landowners
nervous and wary of progressive-sounding theories
collecting supporting data & recruiting supporters
including Alfred Wallace
Ended with the Wallace letter (1858)
Alfred Russel Wallace (1923-1913) Theory Of Evolution Through Natural Selection
Younger biologist / naturalist; biogeography
Also studies Thomas Malthus
Corresponded with D (1857…); D knew his work
On the Tendency of Varieties to Depart Indefinitely From the Original Type (6/1958)
Requested Darwin review & pass it on to Charles Lyell
outlined mechanics of an evolutionary divergence of species due to environmental pressures
D sent to Lyell – L put together with some of D’s writings & published (little notice)
On the Origin of Species 1959
Darwin’s Theory of Evolution
Natural Selection is the Key
Spontaneous Individual Variation
Some variations “favorable”
Increase survival long enough to reproduce
These variations “selected” by nature & passed on
i.e., natural selection
VERY LONG timeline
Note: survival of the best adapted (not the ‘fittest’)
Note: species not individual
Cf: ‘find food, don’t be food’
The Oxford Debates (1860 Brit AAS)
Bishop Wilberforce
A member of House of Lords & Royal Society (No Dope!!)
Darwin's not supported by the fact
greatest names in science were opposed to the theory
‘Humans did not descend from apes’
Thomas Huxley ‘Darwin’s bulldog’
Self taught/apprenticed anatomist
Coined term Agnostic
‘professional scientists’ rather than clergy & amateurs
W: asked Huxley if he descended from an ape on his mother's side or his father's side
H: he would rather be descended from an ape than a man who misused his great talents to suppress debate
Scientific acceptance
By decade’s end, most agreed that evolution occurred
BUT only a minority supported natural selection
Darwin & Psychology
‘In the distant future I see open fields for more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation.’
Comparative Psychology
Humans & animals descended from common ancestor
Functionalism: Chapters 7 and 8
Individual Differences
Pre-D: averages & similarities
Post-D: what human traits make some more successful than others
Evolutionary Psychology: modern evocation
Support for bio explanation of psych concepts
The Origins of Comparative Psychology
Expressions of the Emotions in Man and Animals Darwin (1872): 3 Principles
Expressions: important communicative function
Serviceable Habits
emotion expressions are evolved and adaptive
raising eyebrows: increase VF
Sneer: snowing canine teeth; threat
Antithesis
the exact opposite signals to convey the exact opposite emotion (vs Serviceable Habits)
Shrug is opposite of aggressive stance
Direct Action of the Excited Nervous System on the Body
nervous system needs to discharge excess excitement
Douglas Spalding (1840-1877)
Instinct (Argued against British Empiricist view )
Imprinting; Critical period
George Romanes (1848-1894)
“founder” of comparative psychology
Friend of Darwin; access to his notes
animal behavior in evolutionary context
Animal Intelligence (1882)
anecdotal data; Journalism criterion; overly anthropomorphic
C. Lloyd Morgan (1852-1936)
Introduction to Comparative Psychology (1894)
Lloyd Morgan’s Canon (B.F.Skinner used)
"In no case may we interpret an action as the outcome of the exercise of a higher psychical faculty, if it can be interpreted as the outcome of one which stands lower in the psychological scale.”
Law of Parsimony (Occam's razor)
Cf: Don’t take loans on intelligence
Individual Differences Sir Francis Galton (1822-1911)
Charles Darwin’s Cousin (had access to raw data)
apply evolutionary thinking to the question of intelligence
Issue: regression to mean – how could evolution occur?
1st to note importance of individuals differences
Studying variations in human ability
Hereditary Genius (1869) ( http://galton.org/books/hereditary-genius/)
Success due to superior qualities passed through heredity
Eminence rates
Surveys and twin studies
Conclusion: intelligence/ability/eminence was inherited
Galton eventually rejected; other factors involved in success
Implications: Eugenics (Galton coined term)
forbid reproduction of “degenerate” and “unfit” people
Need for accurate measurements
Galton (Methodological Contrib.)
Statistical investigation of data needed Large Sample
psychometrics
Anthropometric lab
International Health Exhibition held in London in 1885
Measurements based on
Physical measures & Sensory/motor capacity
Related through “correlations”
Some Other Contributions:
Correlation
mental imagery tests
percentiles
questionnaires
regression
scatterplots
twin studies
word association tests
