1. Physiological Roots of Psychology

2. Contributions to Founding of Psychology
Philosophers
Deductive and inductive reasoning
Raised many of the basic questions psychological research addresses today
Physiologists
The methodological systems for testing proposed answers to these questions

3. Goals of early physiological research
Neuroanatomy – attempted to determine if function could be localized in the nervous system and how it was localized
Neurophysiology – attempted to identify how nerves worked

4. Major contributors Neuroanatomy – Gall, Flouren, Broca, and Wernicke
Neurophysiology – Bell, Magendie, Muller, and Helmholtz (Mentor to Wilhelm Wundt)

5. Function of the spinal nerves
Difference in function between dorsal nerves, entering the back of the spinal cord , and the ventral nerves leaving the front.
Magendie – French physician
1822 – described the function correctly dorsal nerves carry snsory information; ventral related to movement
Experimental methods systematic and of a high quality
Identified the reflex arc that became the framework for psychology’s stimulus->response

6. Controversy Bell – an English neuroanatomist
Claimed he had discovered this first and published it in a private publication
Demanded credit for the discovery or he claimed “priority”
His description of the functions was wrong
Ventral nerves voluntary movement
Dorsal nerves involuntary movement
Magendie read Bell’s paper said it was similar but not enough to quit his claim of priority

7. Controversy (cont.) Final outcome was the Bell-Magendie Law
In reality, Bell had no claim to the finding
Magendie used better experimental methods
Magendie findings more complete and definitive
His conclusions were clear and correct
Much of Bell’s criticisms were inaccurate and unrelated to the issue
There was extensive evidence that Bell alstered his early work to support his claim

8. Bell’s contribution
After Magendie published his paper, Bell made his most significant contributiions
Since nerves intervene between the world and our perceptions, nerve activity can influence the quality of our perceptions
The sensation a person experiences depends upon not only the stimulus but upon which nerve was active

9. Muller and the doctrine of Nerve Specificity
5 kinds of nerves one for each sensory ability. Each carried only one type of sensory information
Failure of Muller –
Attempted to measure the speed of nerve conduction and was unable to do so because inadequate measuring devices
Concluded that nerve impulses were instantaneous and therefore could not be measured

10. Muller and “vitalism”
Vitalism –Life processes could not be explained by the interaction of physical and chemical processes alone. Life was more than a physical process and could not be reduced to physical processes. Therefore there is a life force that was beyond scientific study

11. Herman von Helmholtz
Rejected vitalism – nothing mysterious about life; it could be studied using physical and chemical methods of inquiry – the same laws that apply to nonliving things apply to living things
Example Principle of Conservation of Energy

12. Contributions of von Helmholtz
He developed equipment that could measure nerve impulses – they were not instantaneous – activity of nervous system could be studied. Motor neuron in frog had impulses of 43 meters/second
Speed of nerve conduction in humans much slower than previously thought and could be measured
Importance to development of psychology – mental actions could be measured and studied

13. Important example
F.C. Donders – Dutch physiologist described 3 types of reaction times
A-reaction time – simple s->r
B-reaction time – see many stimuli (one at a time) make a discrimination - choose the correct response to make
C-reaction time – see many stimuli respond only to1 of the stimuli
Each of these reaction times could be measured and used to calculate the speed of mental processing

14. Example (cont.) Measure A-reaction time: Measure B-reaction time:
Bell -> Push button
Measure B-reaction time:
Bell or light presented; press red button for bell or press blue button if light present
Measure C-reaction time:
Bell or light presented; press button if bell rung
Subtract A from B to determine time needed to make discrimination between two stimuli
Subtract C from B to determine time needed to determine the correct response

15. Von Helmholtz – Theory of Perception
Sensations are the raw elements of conscious experience; they result from physical activity of different sensory organs
Perceptions are sensations converted by past experience – past experiences give meaning to sensations by turning them into perceptions
Theory of color vision – Young-Helmholtz Trichromatic Theory

16. Helmholtz’s major influence
Psychological events could be studied using scientific methods
Studying and measuring the relationship between physical events and mental experiences naturally led to experimental psychology
Helmholtz was never a psychologist

17. Localization of Function

18. Franz Gall – Phrenology 1810-1819
A person’s personality characteristics could be determined by the size of different bumps on the head
Concept that physical features could indicate psychological characteristics very popular at the time
Darwin almost excluded from trip on HMS Beagle because the Captain didn’t think his nose shape was that of a sailor

19. Gall’s error with Phrenology
His assumption that the shape of the skull was related to the size of the underlying areas of brain
His “faculties” of personality were arbitrary and undefendable
Confirmation bias – only presented cases that were consistent with his theory and discounted evidence that contradicted it

20. Phrenology
Quickly rejected and ridiculed by scientific community – extreme reaction fueled by Gall not one of the inner circle
Rejected by Catholic Church and books banned
Gall’s response was to go on speaking tour making money using an invalid theory

21. Ignored contributions of Gall
Higher cognitive processes related to the cortex, the more cortex an animal had the higher its mental functions
1st to describe 2 forms of matter in CNS and what they consisted of
1st to identify the interconnections between the hemispheres as made up of nerve bundles
1st to describe the crossing over of nerve fibers in the spinal cord

22. Pierre Flouren’s Experiments 1820-1830’s
Most serious challenge to Gall and phrenology
Criticized Gall for improper methology
Experiments removed slices of brain from live animals, then measured behavioral changes
Gall centered sex drive in an area now know as the cerebellum in the back of the brain
Flouren showed that removal of this area affected motor activity and coordination
Removed other areas and found different results than predicted by phrenology

23. Debate
Gall criticized Flourens studies by saying Flouren had removed extremely large amounts of tissue and had removed multiple areas resulting in extensive damage
Finding Gall couldn’t respond to – recovery of function; sometimes animals regained a lost function

24. Flouren’s error
The very large size of his lesions and his adamant rejection of phrenology led him to reject localization of functioning in the cortex
The only localization of function was the cortex was the “seat of will” and the cerebellum was involved in muscle coordination
Adopted unity of function

25. Phrenology, Mesmerism, Perkinism, and Acupuncture
Popularity of phrenology continued in the general public despite scientific rejection
Mesmerism, Perkinism, and acupuncture were summarily ejected, and disappeared
Phrenology consistent with popular beliefs –physical characteristics could indicate personality traits; others were not
Issue not addressed – if these were useless cures, why did they sometimes work?

26. Unrecognized contributions of Phrenology
1st systematic scientific attempt at behavior research
1st attempt at applied psychology
1st attempt at physiological psychology

27. The end of unity of function
Famous case of Phineas Gage
Studies of Pierre-Paul Broca
French physician and strong supporter of Flouren’s unity of function

28. Broca’s change of mind
1861 Ernest Aubertin presented a single case study of a person who had lost his speech and had increasing right side paralysis. He predicted that damage in the frontal lobes would be found.
April 4, Broca argued against this idea of localization o speech
A few days later Broca given a similar case

29. Case history Patient normal until loss of speech
10 years later – weakness in right arm developed into paralysis
4 years later – paralysis spread down right side until he could no longer stand
7 years later bed ridden with loss of sensation on right side – intellect intact
Patient died April 17, 1861
Autopsy showed large lesion centered in lower area of left frontal lobe

30. Broca’s Area?
Broca admitted he was wrong and continued to study the rain and case history
He determined that the center of the lesion must be where speech was located
That was where the most damage was so it was where the lesion began
The patient’s 1st deficit was a lack of speech
Auberton not interested in studying the brain after he was shown to be correct
Broca found the precise area involved in speech production

31. Localization of function (cont.)
1874 – Wernicke reported that an area of the temporal lobe was responsible for language comprehension
’s – great use of lesion work with nonhumans to further localize function in the cortex
1870’s – began electrical stimulation of nonhuman animal brains

32. Electrical stimulation
Most important was the work of David Ferrier
1876 – reported localization of different sensory and motor functions in many nonhuman animals
Later, he so precisely mapped functions in the monkey that his maps were used to remove a tumor in a human for the 1st time in history
Bartholomew – 1874 – reported results of electrical stimulation of a human brain
Raised ethical questions and he was run out of town

33. Electrical stimulation
Electrical stimulation continues today in both nonhumans and humans
In humans, it is done during neurosurgery to locate functional areas because there tends to be large individual differences

34. Important point in history for psychology
Philosophers have developed the general questions psychologists will address
Studies of the nervous system, psychophysics, physiology, etc. have applied the scientific method to the study of mental function
They have also shown that we can measure mental processes.
Finding that different mental processes involve different parts of the brain indicates they function differently