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!