Physiological Roots of
Psychology
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
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
Major contributors
• Neuroanatomy – Gall, Flouren, Broca, and
Wernicke
• Neurophysiology – Bell, Magendie, Muller,
and Helmholtz (Mentor to Wilhelm Wundt)
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
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
Controversy (cont.)
• Final outcome was the Bell-Magendie Law
• In reality, Bell had no claim to the finding
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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
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
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
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
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
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
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
Example (cont.)
• Measure A-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
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
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
Localization of Function
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
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
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
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
Pierre Flouren’s Experiments 18201830’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
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
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
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?
Unrecognized contributions of
Phrenology
• 1st systematic scientific attempt at
behavior research
• 1st attempt at applied psychology
• 1st attempt at physiological psychology
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
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, 1861 - Broca argued against this idea of
localization o speech
• A few days later Broca given a similar case
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
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
Localization of function (cont.)
• 1874 – Wernicke reported that an area of
the temporal lobe was responsible for
language comprehension
• 1860-1870’s – great use of lesion work
with nonhumans to further localize function
in the cortex
• 1870’s – began electrical stimulation of
nonhuman animal brains
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
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
Important point in history for
psychology
• 1870’s
• 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