th
19
Century Precursors
Psychology 4006
Introduction
• The knowledge of the renaissance was
finally hitting the masses.
• The industrial revolution made it so
people had jobs, and kids would go to
school.
• You didn’t necessarily have the same job
as your father.
• The 19th Century was really a great
upheaval in society.
The Species Problem
• The “mystery of mysteries”
• What accounts for the large number, the diversity, the occasional
disappearance, the existence of fossils, etc.?
• Big problem for academics in the UK
• they were also clergy
• William Paley the argument from design
• Elegant design requires a designer (i.e., God)
Early Evolutionary Ideas
• Early evolutionary ideas
• Erasmus Darwin – evolution from a
single “filament”
• Jean-Baptiste Pierre Antoine de
Monet, Chevalier de Lamarck
• Chain of being
• Inheritance of acquired characteristics
One of my Heroes
• Charles Darwin (1809-1882)
• False starts medicine, clergy
• Finds life’s work at Cambridge
• Influence of Henslow (biology) and Sedgewick (geology)
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Voyage of the Beagle
Contributions to geology
Supported Lyell’s “uniformitarian” views
Contributions to biology
Huge specimen collection
Galápagos episode
Finch varieties (not noticed at the time of his visit
If Aliens Ever Come To Earth….
• Elements of the theory
• Individual variation
• Some variations “favorable”
• Increase chances of surviving the struggle for existence
• These variations “selected” by nature
• i.e., natural selection
Reaction
• The Oxford debates
• Huxley ‘Darwin’s bulldog’
• Scientific acceptance
• The personalistic vs. naturalistic issue again
• Evolution “in the air”
• But Darwin a prime mover
Darwin and Psychology
• Functionalist thinking
• Led to comparative psychology
• Continuity and difference among species
• Led to study of individual variation
• Individual differences
• Modern evocation
• Evolutionary psychology
Comparative Psych, It’s What The Cool Kids
Take
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Darwin ‘Expressions of the Emotions in Man and Animals’ (1872)
Serviceable associated habits
Antithesis
Direct action of nervous system
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Douglas Spalding (1840-1877)
Instinct
Argued against British Empiricist view
Imprinting
Critical periods
Individual Differences
• Sir Francis Galton (1822-1911)
• Numerous non-psychology contributions
• Exploration, meteorology, fingerprinting
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Desired to apply evolutionary thinking to the question of intelligence
Eminence rates
Hereditary Genius (1869)
Surveys and twin studies
Converged on conclusion that intelligence was inherited
• Implications
• Eugenics
• Need for accurate measurements
Galton
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Anthropometric lab – Measurements based on
Physical measures
Sensory/motor capacity
Related through “correlations”
• Studying imagery
• Misinterpreted his own data
• Scientists showed more imagery than he realized
• Studying association
• Word association test
• Hinted at unconscious
Johann Friedrich Herbart (1776-1841)
• He took a psychological approach to
educational problems.
• He attempted to quantify phenomena
in psychology.
• studied apperception, mental
operations more complex than sense
perception
• the goal of education was to build the
apperceptive mass.
• Education must also be moral
education.
Psychophysics, Que-est-ce que c’est
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Ernst Weber (1795-1878) - Leipzig
interested in sensory processes other than vision and hearing
research on two-point thresholds
Mapping skin sensitivity
Weber’s Law
Weight-lifting studies
jnd = just noticeable difference between weights
jnd’s were proportional to the size of the smaller weight
jnd/S = k
If 30g and 33g are just noticeably different, then 60g and 63g will not be
noticeably different (must be 60g and 66g)
No, really, actually psychology!
• Gustav Fechner (1801-1889)
• Systematic analysis of psychophysics
• Relationship between physical stimulus and psychological
experience of it
• Elements of Psychophysics (1860)
• Inspiration came 10 years before
• Fechner Day October 22
• Methods for determining absolute and difference thresholds
• Limits
• Constant stimuli
• Adjustment
Early ‘Neuroscience’
• The Bell-Magendie Law
• Posterior roots of spinal cord control sensation
• Anterior roots control motor movement
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The specific energies of nerves
credited to Johannes Müller
Two parts
We do not perceive the world directly, but rather the action of our nervous system
Nerves corresponding to different senses have different “specific energies”
2 different stimuli, one type of nerve, one type of sensation
1 stimulus, two different types of nerves, two types of sensation
Helmholtz
• Hermann Helmholtz (1821-1894)
• (as an aside, did everyone just look
super intense back then?)
• Speed of the neural impulse
• Relative slowness demonstrated that
physical/chemical processes involved
• the basis for the development of
reaction time methods
Helmholtz
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Research on vision
Trichromatic theory (Young-Helmholtz)
Receptors for three primary colors – red, green, blue/violet
Other colors involved combinations of receptors
Still accepted at the retinal level
• Research on hearing
• Resonance theory
• Different frequencies detected by receptors in different locations on the
cochlea
Localization of Brain Function
• Franz Joseph Gall (1758-1828)
• Proposed craniometry later called phrenology
• observed relations between head shape and individual’s personality or ability
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Basic principles of phrenology
brain is the organ of the mind
mind composed of a number of “faculties”
Intellectual, affective (emotional), personality
each faculty located in a specific place on the cortex
Phrenology First serious localization theory
strength of a faculty reflected in proportional brain size
skull reflects brain contour
Enables measurement of faculties by measuring skulls
Phrenology
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Problems with phrenology
Relied too much on anecdotal evidence
Avoided falsification
Apparent disproof explained away (combo of other faculties)
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Popular in U.S.
Consistent with American values
Opportunity
Uniqueness
Application
Actual Real Localization of Brain Function
• Case of Phineas Gage
• Accident results in serious brain
damage
• changes in behavior lead to
inferences about the affected
portion of brain
• For Gage severe frontal lobe
damage altered rational control
over emotions
Broca
• Case of “Tan”
• Paul Broca (1824-1880)
• Some behavioral/emotional problem occurs
• Correlated with brain damage upon autopsy
• For Tan loss of productive speech (motor aphasia) led to labeling of
“Broca’s area” in left hemisphere
Conclusions
• Don’t ever underestimate the importance of evolutionary thinking to
psychology
• Now we see the importance not of philosophy but of biology