Physiological Roots of Psychology

Physiological Roots of
Contributions to Founding of
• 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
• 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
• 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
– Identified the reflex arc that became the framework for
psychology’s stimulus->response
• 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
– 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
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
• 5 kinds of nerves one for each sensory ability.
Each carried only one type of sensory
• 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
• Speed of nerve conduction in humans much
slower than previously thought and could be
• 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
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
• 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
• 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
• Concept that physical features could indicate
psychological characteristics very popular at the
– 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
• Quickly rejected and ridiculed by scientific
community – extreme reaction fueled by
Gall not one of the inner circle
• Rejected by Catholic Church and books
• 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
• Gall criticized Flourens studies by saying
Flouren had removed extremely large
amounts of tissue and had removed
multiple areas resulting in extensive
• 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
• 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
• 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
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
• 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
• Finding that different mental processes involve different
parts of the brain indicates they function differently