Those who do not know the
history of their field are
doomed to repeat its
mistakes
(Santayana)
PHILOSOPHY
(600BCpresent)
BIOLOGY
(15th century present)
PSYCHOLOGY
(2nd half of 19th century present)
PRE-GREEK ZEITGEIST
People observed alternations of rhythms: day and night,
seasons, famines, etc.
Awareness and recall of dreams: images of dead people,
animals, composites. Concerns about the nature of
things, - Cosmologies devised as explanations.
Motivation for cosmologies was not scientific, e.g.,
predicting eclipses, droughts, etc. That was engineering,
not science.
Cosmologists formulated hypotheses about the basic
units of things: - water, fire, air, earth, numbers.
Pythagoras is a well known example. He believed that
numbers held the secret of everything.
REDUCTIONISM
Democritus was the first cosmologist to
attempt to explain things by reductionism.
In about 400 BC, Democritus postulated that
atoms were the basic unit of all matter and
that there were two types of atoms:
-body atoms (inert)
-soul atoms (vital substance)
Democritus is also credited with
introducing the mind-body distinction.
DYNAMIC VS. RELATIONAL COSMOLOGIES:
Dynamic (Heraclitus): Things are always in flux.
Consciousness is never the same at
successive points of time.
-A basic problem for all sciences: how do
static units change over time?
Relational (Anaxagoras): It is not meaningful to
talk about elementary units without specifying
their organization. The whole is greater than the
sum of its parts.
REACTIONS TO COSMOLOGIES
How do we know about reality?
-Through senses?
-Are the senses trustworthy?
Epistemology: What is the nature of
knowledge?
Sophists: There is no absolute knowledge.
We only know what our senses tell us.
Plato (Socrates?) & Aristotle
Plato:
Rejected relativism of Sophists and
sharpened the mind-body distinction: Reason
supplements what we learn through sense organs
and functions independently of the senses.
The function of the soul is to apprehend
ideal knowledge of the world through reason, to
provide a means of going beyond the imperfect data
of the senses and for defining the universals of
beauty, goodness, mathematics, etc. (cf. Descartes,
Kant, Chomsky).
Aristotle:
Defined the empiristic point of view [tabula
rasa]. He did not accept the universals of
knowledge that Plato postulated.
Aristotle
(384 -322 BC)
Mind should be interpreted,
not as a thing, but as a
process. Perhaps he would
prefer to say "minding" as a
verb rather than "mind" as a
noun. Believed that Mind was
in the heart.
GREEK HERITAGE
Dualism: mind vs. body:
What is the nature of each entity?
How do they interact? basic question of modern behavioral and
cognitive
psychology.
Materialism vs. Idealism:
Materialists: everything is reducible to some physical entity.
Idealists: ideas exist independently of any material substance
(Descartes, Kant, Chomsky)
Nativism vs. Empiricism:
Nativists: Knowledge exists independently of experience
(knowledge may be material, e.g., brain states as postulated by
modern theories of in neuroscience).
Empiricists: Knowledge derives from experience. The
empiricist
object
rasa as
view defines a basic question in the study of language,
recognition, etc. Behaviorists regard the concept of tabula
basic.
SCIENCE vs. ENGINEERING
SCIENCE:
Theory of Gravitation
Theory of Molecular Weights
ENGINEERING:
Dropping objects at
different heights
Fermenting wines
Theory of Evolution
Breeding race horses
Theory of Color Vision
Rules of additive and
subtractive color mixture
Animal training,
Mnemonics
Theory of Behavior
The Reflex Arc
Rene Descartes (1596-1650)
The Reflex
Descartes
Postulated two types of substance:
1. Material (body) extended substance: Occupies
Newtonian space.
2. Soul (thinking) unextended matter: Does not
occupy Newtonian space.
-Thinking matter, unique to man, is the seat of innate
ideas.
-Body and soul interact in the pineal gland (but do not
reside there).
-Animals, who have no souls are mere automatons:
mechanical robot-like creatures.
Two Cartesian heritages:
-mechanical action (reflexes)
-modern view of innate ideas--picked up by Kant & Chomsky.
Reflex:
CONCEPT OF THE REFLEX
A correlation between a stimulus and a
response. The stimulus releases the response, as pulling a
trigger fires a bullet.
*Animal spirits: flowed in hollow tubes from sense organ to muscles.
*Glisson: Disproved the hypothesis of animal spirits by showing that
excised muscle tissue contracts when stimulated (in a dish of saline
solution). These experiments gave rise to the concept of irritability and
excitability.
*Concept of “Spinal mind”: suggested by results of experiment on the
magnitude of the flexion reflex in frogs whose spinal cord were severed
(“spinal preparation”)
*Pflüger: Inferred spinal mind because of variability in the magnitude of
flexion reflex.
*Magnus: Showed that variability was due to uncontrolled shifts in
JOHN LOCKE
*Emphasized the basic role of experience: (1690
Essay Concerning Human Uunderstanding.)
*Resurrected Aristotle's concept of tabula rasa.
*How does tabula rasa get impressed?
*Introduced ideas as the basic unit of the mind
and the concept of mental chemistry: how simple
and complex ideas interact.
Mental Chemistry
Simple ideas (sensations).
Complex ideas (reflection, thought, perception).
Ideas can have either of the following
qualities:
-Primary qualities: quantitative
properties of an object (e.g., mass, motion,
temperature, etc.).
-Secondary qualities: in the "eye"
of the beholder (qualitative differences: colors,
sounds, tastes, etc.).
British School of Empiricism
Berkely: claimed that all ideas were secondary in nature.
God insures stability of world because He has primary ideas.
Hume: Doubted existence of mind and God. All we have is
a collection of ideas. What we must discover are the principles of
association of those ideas (Aristotle), Hume proposed as principles
of association (after Aristotle): resemblance, contiguity, and cause
and effect (temporal succession).
Hartley:
Placed ideas in nervous system and
hypothesized that they obey Newtonian laws.
James Mill:
elements.
All ideas are reducible to simple sensory
Ronald Knox:
There was a young man who said,
God must think it exceedingly
odd if he finds that this tree
continues to be when there is
no one about in the Quad.
Reply:
Dear Sir:
Your astonishment’s odd:
I am always about in the Quad
and that is why the tree
will continue to be
since observed by
Yours faithfully,
God
RELEVANT DEVELOPMENTS IN BIOLOGY
*Reflexology
*Sensory physiology
*Theory of evolution
SENSORY PSYCHOLOGY
Developed out of ancient concern to understand senses.
Knowledge of sensory psychology was facilitated by:
assumption that the body obeyed mechanical laws.
advances in resolution of the microscope.
the discovery of nerves
Bell and Megendie: Discovered independently the
difference between sensory (dorsal) and motor (ventral) nerves.
Müller: How many types of sensory nerves are there? Law
of Specific Nerve Energies.
Helmholtz: Hypothesized specific nerve energies for primary
colors - red, green, blue.
Gall: Phrenology.
TABLE OF SENSATONS
eye
ear
nose
tongue
skin
muscle
tendon
joint
alimentary canal
blood vessels
lungs
sex organs
ear (static sense)
-------
32,820
?
Total:
44,435
4
4
2
1
1
3
?
1?
1
1
1
(From E. B. Titchener “An Outline of Psychology”, NY:
Macmillan, 1896 pp. 74-75.
PSYCHOPHYSICS
Sensory psychologists often asked subjects to make judgments. This
gave rise to various mathematical generalizations about sensory
function.
Weber’s Law: ∆I/I = K [DIFFERENCE THRESHOLD]
I = Physical magnitude of stimulus
∆I = Physical magnitude of change needed to
produce a just noticeable difference (jnd)
K = constant
Fechner’s Law: S = Klog I
S = Subjective magnitude of stimulus
I = Physical magnitude of stimulus
K = constant
Stevens Law: S = KIn
S = Subjective magnitude of stimulus
n = exponent whose value varies with sense modality
K = constant
I = Physical magnitude of stimulus
Theory Of Evolution
Three aspects relevant to
psychology:
- Variation
- Continuity of Structure
- Functionalism
Charles Darwin
“We have seen … [that] man bears in his bodily
structures clear traces of his descent from some
lower form; but it may be urged that, as man
differs so greatly in his mental power from all
other animals, there must be some error in this
conclusion....It can be shown [that] there is no
fundamental difference of this kind. We must
also admit that there is a much wider interval in
mental power between one of the lowest fishes,
as a lamprey or lancelet, and one of the higher
apes, than between an ape and man; yet this
interval is filled up by numberless gradations. ”
(Darwin, 1871/1982a, p. 445 )
VARIATION
Charles Darwin and his disciple Herbert
Spencer, argued that the logic of variation and
selection also applied to behavior. Note the similarity
with respect to the logic of reinforcement theory.
Galton: Observed that intellectual ability varied
between individuals (just as structural features vary).
-Asked how can variation of intellectual
ability be measured?
-Argued for sensory ability as a measure of
intelligence.
-Experiments on individual differences led to
development of I.Q. and other psychological tests.
-Assumed that intelligence is innate.
BEHAVIORAL ADAPTATIONS
Examples of Continuity of Biological Structure:
-eyes
-breathing apparatus
-digestive systems
-camouflage
-musculature
Comparative psychologists ask, is there continuity of
mental ability and consciousness between animal and
man?
Modern examples of continuity:
a. instincts - study of ethology
b. reflexes - conditioned & unconditioned
reflexes
Clever Hans
Morgan’s Canon of Parsimony
Clever Hans
FUNCTIONALISM
Darwin: Structures are adaptive because they
assume a certain function.
-Search for structure can be facilitated by
studying function.
-Structure can be inferred from function, e.g.,
research in physiological psychology.
William James: What is the function of
consciousness? That topic is central to modern
psychology.
NEWTON
HARVEY
PLATO
DESCARTES
REFLEXOLOGY
SENSORY PSYCHOLOGY
THEORY OF EVOLUTION
BRITISH EMPIRICISM
INTROSPECTION
PSYCHOPHYSICS
COGNITIVE PSYCHOLOGY