1. Physiological Influences on Psychology
Lecture Prepared by: Ms. Wilson, MS, LPC

2. The Importance of the Human Observer
David Kinnebrook:
Assistant to Reverend Nevil Maskelyne, the Royal Astronomer
Worked at the Royal Observatory (Greenwich, England)
Job was lonely, tedious, and highly demanding
Noted times of star movements

3. Friedrich Wilhelm Bessel 1784-1846
David K. Makes a Mistake: The Importance of the Human Observer (cont’d.)
20 years later:
Bessel: investigated David K’s errors
“Personal equation”: there are personal differences among people over which they have no control
Two conclusions:
Astronomy affected by the human observer
Human observer is important to all sciences
Friedrich Wilhelm Bessel

4. Developments in Early Physiology
Antecedents:
Johannes Muller ( )
Handbook of physiology of mankind
Specific energies of nerves
Example: stimulating the eye with different objects
Specific Irritability-Adequate stimulation
Johannes Muller ( )

5. Developments in Early Physiology (cont’d.)
Research on brain functions: mapping from the outside
Franz Josef Gall ( )
Does the brain size and shape reveal any information?
Proposition: Larger brains were more intelligent?
Phrenology: belief that mental characteristics correspond to bulges on the skull

6. Phrenology
Every psychological function is dependent on specific region of the brain
Mind can be meaningfully and satisfactorily analyzed into thirty seven faculties
Johann Spurzheim
Popularized the practice of phrenology with books and demonstrations of its uses.
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7. Developments in Early Physiology
Research on brain functions: mapping from the inside
Attempts to determine brain function
Extirpation
Clinical Method
Electrical Stimulation

8. Research on brain function
High interest in brain localization functions
Pierre Flourens ( )
professor of natural history in Paris
Brain acts as a functional entity
used extirpation
Cerebral hemisphere was responsible for higher cognitive functions.

9. Developments in Early Physiology
Research on brain functions: mapping from the inside
Marshall Hall ( )
Observed movements of decapitated animals
Different levels of behavior arise from different parts of the brain and nervous system
Voluntary movements
Respiratory movements
Involuntary movements
Reflex movements
Marshall Hall ( )

10. Research on brain function
. Paul Broca ( )
1861: the clinical method
Using the clinical method (observations in the clinical setting), they were able to localize language and communication functions in the brain.
Case of Patient Tan
Broca’s area: speech center

11. Research on brain function
Gustav Fritsch and Eduard Hitzig
1870: electrical stimulation method
Set out to electrically stimulate the cortex of a dog.
Exposed the surface of the dog’s cerebral cortex and applied galvanic stimulation.
stimulation of certain cortical areas results in motor responses
This was considered as the beginning of modern neurophysiology

12. Developments in Early Physiology (cont’d.)
Research on the nervous system
Luigi Galvani: found that nerves are electrical
Ramon y Cajal: discovered the direction of travel for nerve impulses
He received the Nobel prize in physiology for the Neuron doctrine in 1906.

13. The Beginnings of Experimental Psychology
Scientists responsible for initial application of experimentation to mind
Hermann Helmholtz
Ernst Weber
Gustav Fechner
Wilhelm Wundt

14. The Beginnings of Experimental Psychology
Experimental psychology begins in Germany
The German approach to science:
Emphasis on the careful, thorough collection of observable facts
Welcomed the study of biology when other nations did not
The reform movement in German universities:
Freedom unknown to other nations
More resources as compared to Cambridge and Oxford
More research universities
John Hopkins University (1876) was the first research university in the US.

15. Hermann von Helmholtz (1821-1894) : His life
Born in Potsdam, Germany
1838: enrolled at a Berlin medical institute
Seven years as army surgeon
continued to study mathematics and physics
published articles
Emphasized mechanism and determinism
Assumed human sense organs functioned like machines

16. Hermann von Helmholtz (1821-1894)
Principle of conservation of energy
Invented ophthalmoscope
Helmholtz’s contributions to the new psychology:
Investigated the speed of the neural impulse:
Used nerves of different lengths and recorded the delay between stimulation and muscle reaction
Found that neural impulses travel at a rate of 90 ft. per second
Nerve impulses are measurable and slow

17. Hermann von Helmholtz (1821-1894)
Sensations are raw elements of experience and perceptions are sensations after given meaning by the person’s past experience.
To explain the transformation from sensation to perception dependent he relied on the ideas of unconscious inference of past experience.

18. Hermann von Helmholtz (1821-1894)
Research on vision and hearing
Young Helmholtz theory of color vision
Proposed three types of color receptors corresponding to the three primary additive colors
The firing of these receptors in various combinations results in subjective color experiences corresponding to various wavelengths of light.
Theory of auditory perception

19. Earnest Heinrich Weber (1975-1878)
Obtained his doctorate from University of Leipzig.
Interested in the physiology of the sense organs
Demonstrated that sense of touch involves several senses

20. Ernst Weber (1795-1878) Researched physiology of the sense organs
Two-point thresholds: the threshold at which two points of stimulation can be distinguished
Just noticeable difference: the smallest difference that can be detected between two physical stimuli
Just noticeable difference is a constant fraction of the standard weight.
Drew attention to the experimental method

21. Weber’s Law

22. Gustav Theodor Fechner (1801-1887) (cont’d.)
Fechner’s life:
Born in southeastern Germany
Translated texts, introducing him to physics
Professor at Leipzig
Plagued with many illnesses
Eventually cured of his ailments and lived a long life

23. Gustav Theodor Fechner (1801-1887) (cont’d.)
Mind and body: a quantitative relationship
Stimulus increase does not produce corresponding increase in sensation
Relationship not one-to-one
Amount of sensation depends on amount of stimulation
Absolute threshold
Differential threshold
S=K log R

24. Gustav Theodor Fechner (1801-1887) (cont’d.)
Methods of psychophysics:
Fechner introduced psychophysics: the scientific study of the relations between mental and physical processes
Examples of experiments: lifting weights, visual brightness, visual distance, tactile distance
Method of average error (or method of adjustment)
Method of constant stimuli
Method of limits