19th 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 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) 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 Darwin ‘Expressions of the Emotions in Man and Animals’ (1872) Serviceable associated habits Antithesis Direct action of nervous system 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 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 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 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 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 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 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 Problems with phrenology Relied too much on anecdotal evidence Avoided falsification Apparent disproof explained away (combo of other faculties) 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