Early Developments in
Physiology and the
Rise of Experimental
PsychologyChapter 8
Early Interest in Physiology
500 B.C. Alcmaeon: first(?) dissections15th century: Leonardo Da Vinci
-dissections despite papal ban16th century: Michelangelo
-Sistine Chapel -Dissections
16th-17th century Descartes: -Comparative animal dissections-Where does the mind and body interact?
-Most philosophers had their own version of dualism
17th & 18th centuries-European Wars-- Chance to study head trauma-Executions: smiles & winks?
Individual Differences
1795 David Kinnebrook, a research assistant of Nevil Maskelyne, was to assess the precise time that a star crossed the crosshairs of a telescope. He was consistently ½ s different from his advisor. He was fired.
Reaction Time: The period of time between presentation of and response to a stimulus.
Personal Equations: Mathematical formulae used to correct for differences in reaction time among observers.
Discrepancy Between Objective and
Subjective Reality
Discrepancies between a physical event and a
person’s perception of it was of great concern to
natural scientists who viewed their jobs as
accurately describing and explaining the physical
world.
The question of interest to the early scientists was
“How do empirical sense impressions come to be
represented in consciousness?”
Physiology provided the link between mental
philosophy and the science of psychology.
The discrepancy made a science of psychology
almost inevitable.
Bell-Magendie Law
Bell-Magendie Law: There are two
types of nerves: sensory nerves
carrying impulses from the sense
receptors to the brain and motor
nerves carrying impulses from the
brain to the muscles and glands of
the body.
Doctrine of Specific Nerve
Energies
Johannes Müller
Born in Koblenz, Germany
Doctorate from University of Bonn (remember,
the beer drinking students despised by
Nietzsche?)
Was chair of newly created physiology
department at the University of Berlin
Creation of the department signaled acceptance
of physiology as science.
Handbuch der Physiologie des Menschen (1833)
Doctrine of Specific Nerve Energies
Johannes Müller
Doctrine of Specific Nerve Energies:
Each sensory nerve, no matter how
it is stimulated, releases an energy
specific to that nerve.
Thus light, pressure, or
mechanical stimulation acting on
the retina and optic nerve
invariably produces luminous
impressions.
Doctrine of Specific Nerve Energies
Johannes Müller
Adequate Stimulation
All the sense organs are not equally
receptive to all types of stimulation.
Each of the sense organs is maximally
sensitive to a certain type of stimulation
(specific irritability).
Adequate Stimulation: Stimulation to which
a sense modality is maximally sensitive.
Doctrine of Specific Nerve Energies
Johannes Müller
We are Conscious of Sensations, not
Physical Reality Accepted idea
of Kant’s
categories of
thought.
Instead though,
the sensory
systems always
modify the
sensations
before we
perceive them.
Hermann von Helmholtz
Born in Potsdam
Mediocre student, though he spent
his spare time reading science.
Father could not afford to pay for
scientific training.
Interested in natural sciences, but
found a program for free medical
school if he served eight years as
an army surgeon.
Studied under Johannes Müller
Hermann von Helmholtz
Helmholtz’s Stand Against Vitalism
Vitalism: The belief that life cannot be explained solely as the interaction of physical and chemical forces.
Johannes Müller was a vitalist
Materialism: The belief that there is nothing mysterious about life and assumed that it could be explained in terms of physical and chemical processes.
No reason to exclude the study of life from the realm of science.
Hermann von Helmholtz
Principle of Conservation of Energy
Principle of Conservation of Energy: The energy
within a system is constant; therefore, it cannot be
added to or subtracted from but only transformed
from one form to another.
Applies to living organisms as well.
The energy from food and oxygen will equal the
energy expended by muscles and organs.
Clearly a materialistic statement!
Hermann von Helmholtz
Rate of Nerve Conduction
Johannes Müller had maintained that
nerve conduction was instant.
Helmholtz felt nothing was outside the
realm of science.
He isolated a nerve leading to a frog’s leg
muscle.
• He stimulated the nerve at various
points and measured how long for the
muscle to respond.
• Concluded nerve conduction occurs at
27.4 meters per second.
Hermann von Helmholtz
Theory of Perception
Sensation: The rudimentary mental experience caused when sense receptors are stimulated by an environmental stimulus.
Perception: According to Helmholtz, the mental experience arising when sensations are embellished by the recollection of past experiences.
Unconscious Inference: According to Helmholtz, the process by which the remnants of past experience are added to sensations, thereby converting them into perceptions.
Hermann von Helmholtz
Theory of Perception
Previous experience intervenes and makes a sensation into a perception.
An empirical theory of perception.
The innate categories of thought proposed by Kant were actually derived from experience. The axioms of geometry are not innate, they are a
product of the sensations we’ve had.
If the world were different, and we therefore had different sensations, the axioms would be different.
Individuals who had been blind since birth who acquired sight needed to learn to perceive.
Hermann von Helmholtz
Theory of Color Vision
Newton had discovered that pure orange wavelengths were indistinguishable from orange created by mixing red and yellow.
The property of color cannot be in the wavelengths themselves.
Young-Helmholtz Theory of Color Vision: Separate receptor systems on the retina are responsive to each of the three primary colors: red, green, and blue-violet. Also called the trichromatic theory.
An extension of the doctrine of specific nerve energies. Not just a single nerve energy for vision, but three types of receptors on the retina.
Hermann von Helmholtz
Theory of Color Vision
Hermann von Helmholtz
Theory of Auditory Perception
The ear also has multiple
receptors, literally thousands.
Resonance Place Theory of
Auditory Perception: The tiny
fibers on the basilar
membrane of the inner ear
are stimulated by different
frequencies of sound. The
shorter the fiber, the higher
the frequency to which it
responds.
Hermann von Helmholtz
Helmholtz’s Contributions
Though the mind is active, sensations put all
the contents in the mind.
Nerve transmission is not instantaneous.
We can scientifically study internal
processes.
Though the correspondence between the
external and internal world is poor, it is
caused by properties of the sensory
organs and unconscious inferences.
He brought chemistry, physiology, and
psychology together.
Ewald Hering
Received medical degree from University of Leipzig.
Worked with Joseph Breuer.
Took Jan Purkinje’s job at the University of Prague.
Purkinje Shift: As twilight approaches, hues that correspond to short wavelengths such as violet and blue appear brighter than hues corresponding to longer wavelengths such as yellow or red.
• Hints at the phenomenon of negative after images.
Ewald Hering
Space Perception
When stimulated, each point on the
retina provides three types of
information about the stimulus: height,
left-right position, and depth.
Similar to Kant’s categories of
thought, but an innate characteristic
of the eye.
Ewald Hering
Theory of Color Vision
Unexplained by the Young-Helmholtz
theory of color vision, mixing red/green
or blue/yellow or black/white makes
gray.
Similarly, if you stare at red, then
look away, you see a green
afterimage (ditto for BY).
If a color blind person is unable to
see red, then they cannot see green
either (same with BY).
Ewald Hering
Theory of Color Vision
Opponent Process Theory: Three receptors in eye, but each responds in two ways.
One type responds to RG, one to BY, one the BW
R, Y, and W cause a tearing down (catabolic process) and G, B, and B cause a building up (anabolic process).
If the opponent colors are seen simultaneously, then gray results.
Christine Ladd-Franklin
Graduated from Vassar.
Completed requirements for doctorate in
mathematics from Johns Hopkins University,
but denied the doctorate due to her gender.
Given honorary doctorate by Vassar
Eventually given doctorate from Johns
Hopkins.
Studied in Germany under Helmholtz and
Georg Muller (where Hering’s theory was
supported).
Christine Ladd-Franklin
Proposed color vision theory based on
evolution.
Motion detection is most primitive form of
vision.
Color detection is more modern.
• Within color vision, BW vision most
primitive.
• Then comes BY, since it evolved earlier, it
is less likely to be faulty.
• Then comes RG, the newest form is the
one most likely to be problematic.
Early Research on Brain Functioning
Physiognomy: The attempt to
determine a person's character by
analyzing his or her facial features,
bodily structure, and habitual
patterns of posture and movement.
Early Research on Brain Functioning
Cesare Lombroso
Criminality is inherited and the born criminal can
be identified by physical defects which confirm the
criminal is a savage.
Large jaws, forward projection of jaw, Low sloping
forehead
High cheekbones, flattened or upturned nose
Handle-shaped ears
Hawk-like noses or fleshy lips.
Hard Shifty eyes, scanty beard or baldness
Insensitivity to pain, long arms
Early Research on Brain Functioning
Cesare Lombroso
Early Research on Brain Functioning
Phrenology
Franz Joseph Gall
Faculties of the mind act on
and transform sensory
information.
The faculties do not exist to
the same extent in all people.
The faculties are located in
specific areas.
If a faculty is well developed,
the brain will push the skull.
Early Research on Brain Functioning
Phrenology
Franz Joseph Gall
Phrenology: The examination of the bumps and
depressions on the skull in order to determine
the strengths and weaknesses of various
mental faculties.
Developed out of the notion of faculty
psychology.
Early Research on Brain Functioning
Phrenology
Franz Joseph Gall
In the introduction to his main work The Anatomy and Physiology of the Nervous System in General, and of the Brain in Particular, Gall makes the following statement in regard to the principles on which he based his doctrine:
That moral and intellectual faculties are innate
That their exercise or manifestation depends on organization
That the brain is the organ of all the propensities, sentiments and faculties
That the brain is composed of many particular organs as there are propensities, sentiments and faculties which differ essentially from each other.
That the form of the head or cranium represents the form of the brain, and thus reflects the relative
Early Research on Brain Functioning
Phrenology
The Popularity of Phrenology
The Physiognomical System of Drs. Gall and
Spurzheim (1815)
Phrenology provided a possible objective science of
the mind.
Phrenology produced useful predictive information
about people (Formal Discipline).
Early Research on Brain Functioning
Phrenology
The Popularity of Phrenology
The Lavery electric
phrenometer was
invented to increase
precision in
measuring bumps on
the head.
Phrenology used the
phrase “Know
thyself” to promote.
Was Phrenology that far off?
Modern studies using MRI imaging have shown that brain size correlates with IQ (r = 0.35) among adults. A study on twins showed that frontal gray matter volume was correlated with g and highly heritable. A related study has reported that the correlation between brain size (reported to have a heritability of 0.85) and g is 0.4, and that correlation is mediated entirely by genetic factors.
A study involving 307 children (age between six to nineteen) measuring the size of brain structures using magnetic resonance imaging (MRI) and measuring verbal and non-verbal abilities has been conducted (Shaw et al, 2006). The study has indicated that there is a relationship between IQ and the structure of the cortex - the characteristic change being the group with the superior IQ scores starts with thinner cortex in the early age then becomes thicker than average by the late teens.
Early Research on Brain Functioning
Jean Pierre Flourens
Used the method of extirpation, or
ablation, in brain research.
Destroy a part of the brain, then
make note of behavior change.
Flourens assumed that the brains of
lower animals was similar to the
brain of humans.
Early Research on Brain Functioning
Jean Pierre Flourens
Flourens concluded that though there was
some localization, contrary to the
phrenologists, most brain functions require
interrelatedness.
Animals sometimes regained lost
functions following ablations.
Other brain areas had the ability to take
over for the severed area.
Early Research on Brain Functioning
Paul Broca
Clinical Method: The technique that
Broca used. It involves first determining
a behavior disorder in a living patient
and then, after the patient had died,
locating the part of the brain responsible
for the behavior disorder.
Broca's Area: The speech area on the
left frontal lobe of the cortex (the inferior
frontal gyrus).
Early Research on Brain Functioning
Carl Wernicke
Wernicke's Area: The area on the left temporal
lobe of the cortex associated with speech
comprehension.
Though Broca’s and Wernicke’s areas
supported the phrenologist’s basic contention
of localization of brain functions, these
functions were not found where phrenologists
had said they would be.
Phineas Gage (unintentional contributor)
•Railroad construction gang foreman
•Good natured, well liked, hardworking
•Had severe head injury (in 1848)
•Completely changed personality
•“Gage was no longer Gage”
•Frontal lobes damage:
•unreliable, distracted, lack foresight
•Died 12 years later in 1860
Early Research on Brain Functioning
Phineas Gage
Early Research on Brain
Functioning
Gustav Fritsch and Eduard Hitzig
Discovered localization of
motor areas in the cortex
Stimulate an area electrically
and parts of the body reliably
moved
The parts that moved were
the opposite to the side
stimulated.
Early Research on Brain Functioning
David Ferrier
Created a “map” of the motor cortex
using monkeys.
Proposed the monkey map = human
map
Discovered the sensory areas of the
cortex.
Researchers after him discovered
visual and auditory areas.
Early Research on Brain Functioning
Electrical Stimulation of the Human Brain
Roberts Bartholow
Took advantage of a “clinical opportunity”
Mary Rafferty, a 30 yr old domestic worker
was admitted to the hospital for a small ulcer
on her scalp. The skull had worn away
exposing a 2 in. area.
The Rise of Experimental Psychology
Perceptions were triggered by brain processes
which were themselves triggered sensations.
How are the domains of mental sensations and
sensory processes related?
A science of psychology was impossible unless
consciousness could be measured as
objectively as the physical world.
The Rise of Experimental Psychology
Ernst Heinrich Weber
Obtained doctorate from University of Leipzig
and taught there until retirement.
Interested in the senses of touch and
kinesthesis (The sensations caused by
muscular activity).
With his brother Eduard Friedrich Weber he
discovered inhibitory power of the vagus nerve.
With another brother, W. E. Weber, he made
studies of acoustics and wave motion.
The Rise of Experimental Psychology
Ernst Heinrich Weber
Weber’s Work on Touch
Two-point Threshold: The smallest distance between two points of stimulation at which the two points are experienced as two points rather than one.
He used a compass-like device to simultaneously apply pressure to two points on the skin.
On Touch: Anatomical and Physiological Notes(1834) provided charts of the entire body in regards to the two-point threshold.
The Rise of Experimental Psychology
Ernst Heinrich Weber
Weber’s Work on Kinesthesis
Just Noticeable Difference (jnd): The sensation that results if a change in stimulus intensity exceeds the differential threshold.
The Rise of Experimental Psychology
Ernst Heinrich Weber
Judgments are Relative
The jnd is a constant fraction of the standard weight.
For lifted weights it is about 1/40, for non-lifted weights it is about 1/30
Weber's Law: Just noticeable differences correspond to a constant proportion of a standard stimulus.
The Rise of Experimental Psychology
Gustav Theodor Fechner
Obtained medical degree from University of Leipzig.
Shifted from medicine to mathematics and physics.
Published an article on properties of electrical currents.
Made professor of physics at University of Leipzig
Had interest in the mind/body relationship.
Consciousness cannot be separated from material things.
Panpsychism: The belief that everything in the universe experiences consciousness.
The Rise of Experimental Psychology
Gustav Theodor Fechner
The Adventures of Dr. Mises
In addition to Fechner the scientist, there was Fechner the philosopher, spiritualist, and mystic.
Wrote 14 books under pseudonym Dr. Mises.
Proof that the Moon is made of Iodine (1821)
The Comparative Anatomy of Angels (1825)
The Little Book of Life after Death (1836)
Nanna, or Concerning the Mental Life of Plants (1848)
Always expressed view of universe as living and conscious.
The Rise of Experimental Psychology
Gustav Theodor Fechner
Psychophysics
Fechner wanted to solve the mind/body problem in a way that would satisfy materialists of his day.
A systematic relationship between bodily and mental experience could be demonstrated if a person was asked to report changes in sensations as a physical stimulus was systematically varied.
Speculated that physical stimuli would have to vary geometrically in order for sensations to vary arithmetically.
Psychophysics: The systematic study of the relationship between physical and psychological events.
The Rise of Experimental Psychology
Gustav Theodor Fechner
Psychophysics
Weber’s Law
R = Reiz, the German word for stimulus, the standard stimulus.
DR = The minimum change in R that could be detected.
k = constant (as seen earlier, k = 1/40 for lifted weights)
kR
R
D
The Rise of Experimental Psychology
Gustav Theodor Fechner
Absolute Threshold
Absolute Threshold: The smallest amount of stimulation that can be detected by an organism.
The Rise of Experimental Psychology
Gustav Theodor Fechner
Absolute Threshold
Vision-We can see 1 candle 30 miles away - (pretty
low threshold!).
Audition–We can hear a watch tick 20 feet away.
Taste-We can taste 1 tsp. of sugar in 2 gallons of
water.
Smell-We can smell 1 drop of perfume within a 3
room apartment.
Touch-We can feel the sensation of a bee wing
dropped from 1 cm above your back.
The Rise of Experimental Psychology
Gustav Theodor Fechner
The jnd as a Unit of Sensation
The absolute threshold was useful, but only
provided a single point of connection between the
physical world and the psychological world.
Differential Threshold: The amount that stimulation
needs to change before a difference in that
stimulation can be detected.
Given a geometric increase in the level of
stimulus, there will be an arithmetical increase in
the level of sensation.
S = k log R
Electric Shock Very Small
Pitch .003 = 1/333
Deep Pressure .013 = 1/77
Visual Brightness .016 = 1/62
Weight .050 = 1/20
Loudness .088 = 1/11
Smell, Rubber .104 = 1/10
Cutaneous Pressure .136 = 1/7
Taste, saltiness .200 = 1/5
The Rise of Experimental Psychology
Gustav Theodor Fechner
Estimates of Weber Constants
The Rise of Experimental Psychology
Gustav Theodor Fechner
Psychophysical Methods
Method of Limits: A stimulus is presented at
varying intensities along with a standard
(constant) stimulus, to determine the range of
intensities judged to be the same as the
standard. a.k.a. method of just noticeable
differences
The Rise of Experimental Psychology
Gustav Theodor Fechner
Psychophysical Methods
Method of Constant Stimuli: A stimulus is
presented at different intensities along with a
standard stimulus, and the observer reports if it
appears to be greater than, less than, or equal
to the standard. a.k.a. method of right and
wrong cases
The Rise of Experimental Psychology
Gustav Theodor Fechner
Psychophysical Methods
Method of Adjustment: An observer adjusts a
variable stimulus until it appears to be equal to
a standard stimulus. a.k.a. method of average
error
The Rise of Experimental Psychology
Gustav Theodor Fechner
Fechner’s Contributions
Created psychophysics
Created experimental esthetics
Quantify reactions to works of art to discover
why one artwork is better than another.
Predict the “success” of new works!
It is possible to measure mental events and
relate them to physical ones.
Empiricists:
laws, observation,
rigid methodology,
sensory experience
Rationalists
Theory, active mind,
organizing principles,
mental experience,
Physiologists
experiments on
people determinants
of thought and action,
data & PROOF!
THE RISE OF
EXPERIMENTAL
PSYCHOLOGY!!
- experimentally linking
physical & psychological
worlds!